The history of Setra: an idea becomes self-supporting (long version)

  • 1907 sees the introduction of the first dual-purpose vehicle, designed to transport either beer barrels or excursion passengers
  • 1911: two Kässbohrer buses for the German city of Ulm's first bus service
  • Setra: a construction method becomes a brand name
  • The Setra brand, with its rural regular-service buses and premium touring coaches, is today one of the mainstays of EvoBus

Stuttgart/Ulm – the foundation of EvoBus GmbH on 23 February 1995 by the then Mercedes-Benz AG, Stuttgart, and the company Karl Kässbohrer Fahrzeugwerke GmbH, Ulm, brought to an end the 102-year history of the long-established Kässbohrer company. The creation of EvoBus, however, provided the solid basis that would allow the continuing existence of the product name Setra, devised by Otto Kässbohrer in 1951 and now one of the most prestigious European bus and coach brands in Europe.
EvoBus GmbH, the European entity within the international business unit Daimler Buses, was firmly committed to pursuing a two-brand strategy right from the start. Part of this strategy involved leveraging as far as possible the strengths and customer loyalty traditionally associated with the Mercedes-Benz and Setra brands, whilst also continuing to build on them.
Today, Mercedes-Benz Buses offers a unique full-line range of bus chassis and complete vehicles, including everything from a minibus to an articulated bus. The Setra brand offers a range of sophisticated and comfortable vehicles encompassing 23 different models of rural regular-service buses and touring coaches. The ten years between 1995 and 2005 saw the introduction of a total of 60 new products by
Mercedes-Benz and Setra, evidence both of the company's entrepreneurial strength and of advances in the field of emissions technology and vehicle safety. No other cooperation agreement in the history of the European bus and coach industry has brought success that is at all comparable, with so many benefits for both customers and employees.
Even during the due diligence phase of the proposed merger, the prospect of generating synergies through an effective co-ordinated production system was one of the key factors behind the evolving EvoBus company. The EvoBus co-ordinated production system these days encompasses a flexible bus and coach team that cooperates closely across five countries. As well as the former Kässbohrer bus production plant in Neu-Ulm, the system incorporates the tradition-steeped
Mercedes-Benz bus plant in Mannheim, a French site at Ligny-en-Barrois (Lorraine), Sámano in Spain, the Holysov plant in the Czech Republic and a Daimler plant in Istanbul. The network linking these production locations provides a framework that allows bus and coach body shells, fully equipped buses and chassis for the Mercedes-Benz and Setra brands to be manufactured in the most cost-effective way and with maximum synergies. The manufacturing processes at four of these six European locations are directly linked.
The second phase of the integration of Setra as part of EvoBus and thence into the Daimler Buses business unit came with the company's decision to develop a co‑ordinated system for development as well as production. As many of the key principles that are also applied in the research and development of buses and coaches stem from the corporate research area, this was an easy decision to make. The synergies thus achieved bring clear economic advantages, since even the production of 40,000 buses and coaches a year cannot generate sufficient funds for the development of sophisticated alternative drive systems and the high levels of safety required. For around ten years now, Daimler AG has invested millions in creating the world's largest centre of competence for the development of buses and coaches. The Neu-Ulm headquarters for the bus development team of the world market leader is now the largest development centre for buses in the world.
From body-on-frame to today's buses
The brand name Setra comes from the German word "selbsttragend", meaning self-supporting. This construction principle, dating from the early 1950s, brought about a step-change, a revolution even, in bus construction in Germany and throughout Europe. Otto Kässbohrer, who with his brother Karl took over the running of the company in 1922 upon the death of his father, the company's founder Karl Kässbohrer, did not himself invent the self-supporting concept. He was however very familiar with it, having spent many years working on a number of car bodies and learning to apply the principles of the self-supporting vehicle body. Among the vehicles that influenced Otto Kässbohrer's work was the legendary "Lancia Lambda" sports car, for which he had built the body, and which had won many hill climbing races in the late 1920s. The Kässbohrer company in Ulm thus also played a significant part in the history of the automobile, for the brothers Karl and Otto Kässbohrer, each in his own field, correctly gauged the signs of the times and introduced pioneering developments in motorised vehicles: Otto in the field of bus manufacturing and Karl in commercial vehicles. Indeed it was the latter who created the world-renowned ski-run maintenance vehicle known as the "Piste Bully", an innovation he brought to the world's markets in 1969.
The post-war period was a difficult time for all industrial companies in Germany. Most production plants had been severely damaged and materials and machine tools in particular were in short supply. What made things even more difficult for the bus body shell manufacturer Kässbohrer was the fact that chassis suppliers such as Mercedes-Benz, Hanomag, Magirus-Deutz in Ulm, Henschel in Kassel or Krupp did not supply bus-specific versions of their standard truck chassis, so that Kässbohrer were forced to make technical changes to adapt them for use in buses. Otto Kässbohrer recognised that the growing demand for buses and coaches could not be met in this way. He therefore began to think more and more about forging his own way in bus manufacturing.
In 1950, an internal development project known as "KKS" (Karl Kässbohrer self- supporting bus) was initiated with the following justification: "In order to remove dependence on the third-party supply of bus chassis and at the same time to be able to make technical improvements to the bus as a means of transporting passengers, development will commence of a self-supporting bus without separate chassis." The triumphal advance of the resulting Setra began in earnest when six Kässbohrer employees lifted up the skeleton of the prototype, so proving that this revolutionary method of constructing a framework structure with integrated sub-frame made it possible to combine weight optimisation with a high level of stability. The major step from body-on-frame construction to the stand-alone bus had thus been taken.
Over the ensuing years, bus construction was thus able to cast off completely its dependence on the truck chassis and to embark on its own trailblazing journey into the future, where it continues to be characterised, even today, by a wide variety of body shell and equipment styles. Spacious load compartments (roof racks for luggage were now no longer necessary), comfortable interiors and the installation of such things as kitchen facilities, coat hanging space and toilets all became possible. Otto Kässbohrer would not have become the father of the Setra if other innovative advances had not also been included in the emergence of the highly sophisticated integral-body bus. Amongst other features, the heating system provided individual channels for each row of seats. Draught-free ventilation, windscreen defrosting, compressed-air brakes and engine brakes were all introduced. Since that period, which also marked the start of the German economic miracle, there have been five model series of Setra buses – the buses have changed more than their users. Today, 60 years after the first Setra S 8, it can safely be said: some ideas support themselves very successfully.
The Ulmer Box comes ashore
The ancestors of the company's founder had also been involved in the transport business, in the widest possible sense of the word: company founder Karl Kässbohrer, born in 1864, came from a family of bargees and boatmen who had been plying their trade since the 16th century along the River Danube in home-made boats known as "Viennese Zillen" and "Ordinaries". These boats, known more locally as "Ulmer Boxes", were wider than they were deep, in order to be able to navigate the often only shallow waters of what is one of Europe's major rivers. The watermen used them to carry passengers as well as goods as far as Vienna and were highly regarded, for trade along the Danube had been a key factor behind the prosperity of the "Free Imperial City" of Ulm. As the saying went "Ulm's money rules the world".
But in the 19th century, Ulm's watermen were severely hit by competition from the railways. Master shipbuilder Georg Kässbohrer, one of the last practitioners of his trade in Ulm, therefore broke with the family tradition by ensuring that his third son Karl trained as a cartwright rather than in the family's customary trade. With Karl Kässbohrer, therefore, the Ulmer Boxes – at least figuratively speaking – came ashore. His journeyman years as an apprentice carriage builder took him to Vienna, where the experience he gained working with the finest of vehicles would later be put to good use in his own business. In order to differentiate himself from the competition (establishing what we would these days call his Unique Selling Point, or USP), the young master craftsman insisted on the highest quality. "I wish most humbly and respectfully to inform the general public, all ladies and gentlemen of quality and carriage owners that I have recently taken up business as a carriage builder at my address at C 121 Lauterberg and wish to commend myself to you for the manufacture of chaises and carriages of all descriptions and for the repair of said vehicles." – with these words, in an advert in the local newspaper "Ulmer Tagblatt" on 5 September 1893, Karl Kässbohrer launched his own business. Initially he earned his living with repair work, but by the end of the century his prospectus also included the phrase "Manufacturer of luxury and business vehicles." And ultimately he even bore the title of "Purveyor to the Royal Court of Württemberg".
Kässbohrer begins commercial vehicle manufacturing in Ulm
When an opportunity to acquire new, larger premises presented itself to the company's founder in 1903, he seized it. This is the site that would eventually become Ulm's first coachbuilding works. It was also the foundation of what his two sons, Karl (1901–1973) and Otto (1904–1989), would build up over a period of several decades to become the internationally renowned "Karl Kässbohrer Fahrzeugwerke". Kässbohrer established the commercial vehicle manufacturing industry in Ulm, making it for many years the most important industrial sector in the cathedral city and one that provided work for thousands of people through many generations. As far back as 1907, Karl Kässbohrer built a motorised dual-purpose vehicle for a local brewery on a Saurer chassis. During the week it was used to transport beer barrels, while on Sundays it became an excursion bus. The loading floor of this dual-purpose vehicle was divided into two lengthwise and had upholstered seats and backrests that could be folded out of the cavity between the platform and the vehicle frame, so allowing the vehicle to be used to carry goods as well as to transport passengers. This, then, was the nucleus of bus manufacturing at Kässbohrer in Ulm. This 1907 vehicle was patented in 1910. Kässbohrer was thus already active 100 years ago in a vehicle segment in which Setra is still the market leader in Germany today, with multifunctional buses that can be put to good use earning income both on regular-service routes and as occasional tourist coaches.
February 1911 marked a key milestone in the history of Kässbohrer buses. A transport company was established to run a bus route between the town centre and the suburb of Wiblingen. One of the company's shareholders was Karl Kässbohrer, whose stake in the company was represented by a motorised bus on a Saurer chassis, with 18 seats and standing room for ten. The bus featured an early example of the cardan (universal shaft) drive system, a new drive technology that had taken over from the hitherto conventional chain drive system early in the 20th century, and it was powered by a powerful 22 kW four-cylinder engine. The bus body was also ahead of its time: contrary to the convention of the time, the driver here sat in an enclosed cab, the first of its type in the German motor industry. There was additional space for luggage on the roof. The enterprise proved a great success and a second vehicle, again supplied by Kässbohrer, was taken into service in November 1911.
Division of responsibilities pointed the company's way to the future
With its twenty employees, the "Erste Ulmer Karosseriefabrik Karl Kässbohrer" (First Ulm Coachbuilding Works) entered a new and quite exciting decade with the onset of the 1920s: although it was almost impossible at that time to sell trucks, due to the army selling off its stocks, buses were still very much in demand. Then came the sudden and unexpected death of the company's founder in December 1922, when his sons Karl and Otto were just 21 and 18 years old. The older boy, Karl, was studying engineering at the time, while Otto Kässbohrer had completed his apprenticeship as a cartwright in his father's company just six months earlier. Their father's death made all other plans redundant, and the brothers took on the management of the company between them. They ran it with the support of their mother Katharina Kässbohrer (1867–1955) – a hard-working and diligent woman whose ancestors had included the family of Robert Bosch - through the difficult post-war and inflationary period. In due course responsibilities were divided between the brothers: Karl Kässbohrer looked after truck bodies and trailers, Otto took on the bus and passenger car bodies. This shared responsibility, which lasted throughout the brothers' lives, meant that the fledgling company was already clearly orientated towards the needs of the market of the day, so safeguarding its future.
The year 1928 was marked by a concentration on truck bodies and trailers, a vehicle segment with which the name Kässbohrer would soon become synonymous throughout Germany, and the market leader. When it came to passenger car bodies, Otto Kässbohrer was also able to set an interesting marker, shortly before this part of the company's business was abandoned. The last car for which a body was designed, an Italian Lancia Lambda sports car that reached a top speed of 130 km/h and an output of 44kW with its 2370 cc four-cylinder V-engine, set a milestone in automotive engineering. With a wheelbase of 3.10 metres, and weighing 1100 kg, the vehicle in its original version was not agile enough for the very popular hill climbing/road races of the day. Otto Kässbohrer therefore had only the suspension and engine components supplied from Turin - and designed a completely new vehicle body himself for the small series of vehicles that had been commissioned. This body did not have a chassis frame, but was cast in one piece out of high-quality aluminium alloy, thus making it the first self-supporting Kässbohrer vehicle: 23 years before the launch of the Setra. The Lancia from Ulm was 200 kg lighter than the original from Turin and was extremely agile, making it for a considerable period of time the winning car in many motor sport events.
Kässbohrer continues to focus on the very latest engineering
The company founder's policy of only manufacturing high-quality products embodying the very latest technology was maintained by his sons. Kässbohrer had been using pneumatic tyres since the early 1920s and had increasingly adopted the low-frame chassis as well. As there was no such thing at that time as a specific bus chassis, Kässbohrer even went so far as to use specially adapted passenger car chassis with reinforced suspensions for the company's smaller buses, in order to provide a more comfortable ride. The company's so-called panoramic buses, on which the roof could be pushed back all the way to the rear of the vehicle, proved particularly popular.
In 1928, bus operator Franz Schindele from Bad Wörishofen purchased a vehicle like this with three rows of seats, built on a Mercedes-Benz passenger car chassis. Finding it too small for his requirements, he asked for a bus to be built on a two-tonne Mercedes-Benz chassis, which should have large windows all round and a broad sliding roof. Kässbohrer had switched to using sheet-metal panelling some time earlier, but still used wood for the frame of its bus bodies. In order to keep the window uprights as narrow as possible, the Ulm bodyshop here used electrically welded flat-iron sections for the first time. The sliding roof could even be wound down to the height of the seat backrests. But one innovative feature of the Schindele bus of 1929 would go on to become a defining feature of luxury bus travel in the post-war period: the curved, glass-edged roof.
Mercedes-Benz chassis of various sizes had always played an important role as the basis for Kässbohrer bus bodies. The spectrum ranged from the LO 1500 with its three rows of seats, powered by a 33 kW diesel engine, to the three-axle O 10000 chassis with 110 kW engine. A bus such as this, with curved glass roof edging and a sliding roof in two sections, was delivered by Kässbohrer to Cologne in 1938. The "Deutsche Reichspost", the country's postal service, which also occasionally ordered three-axle vehicles with off-road capability for special-purpose use, and the tour operator Max Weigel from Plauen, whose vehicles boasted the name "Silbervogel", or Silver Bird, represented important references for Kässbohrer. In 1939, Kässbohrer launched what was, at the time, the largest bus in the world: an 18.7-metre-long semitrailer bus with 120 seats and standing room for 50, hauled by a Mercedes-Benz LZ 8000 tractor unit.
Until 1939 the workforce continued to grow steadily to around 1000. A site for a new plant had finally been purchased as early as 1934, in what is now the Kässbohrerstrasse, and new production facilities and an office building constructed there. The plant was, however, almost completely destroyed in a major air raid on Ulm in 1944, and by the end of the war only some 200 staff were still employed there.
The foundations of modern bus and coach travel
The 1930s brought about a transformation in bus and coach travel that, in part, presaged the course it would take in the post-war years. In place of what had until now been a basic conveyance of passengers – mostly uncomfortable and with all sorts of negative associations – arose a keen demand for fast and comfortable travel. Kässbohrer played a significant part in this development. Customers travelling in Ulm-built luxury coaches were increasingly pampered, benefiting from reclining seats with adjustable neck bolsters, a toilet, kitchen facilities, and even on-board radio. A new "Aurora Heating" system was introduced, developed by Kässbohrer in conjunction with a company in Leipzig called Aurora Travel: the air for heating the interior, until now heated by the exhaust, was replaced as a heat source by the coolant.
Following the switch from solid tyres to pneumatic ones, six-cylinder engines were used more and more often as a power source. Detailed improvements such as these were also triggered by the construction of many new stretches of autobahn, or motorway, in Germany, where speeds of 100 kilometres or more were now permitted. Aerodynamics, too, played an important part in bus design. From 1935 onwards, Kässbohrer began to build what were known as streamlined buses. In a reflection of the design principles of the day, these adopted the popular teardrop shape. In numerous wind tunnel tests it had very quickly became clear that projecting elements such as headlamps and roof racks increased wind resistance dramatically. Rounded edges and aerodynamic, smooth lines were now the defining characteristics of the new forward-control buses. In most cases the buses were fitted with flat window panes, with diagonal corner windows used for the transition from the slightly inclined front windscreen to the side windows. However, for its luxury long-distance coaches with their more steeply raked front, Kässbohrer used curved panes.
1951: the beginning of the Setra era
It took barely a year after the end of the war for Kässbohrer to revolutionise bus production yet again, following the decision made in the spring of 1950 to develop a bus built along self-supporting design principles. The official launch of the Setra S 8 to the industry was in 1951, at the premises of the company's general distributor in Frankfurt, Kahl, during the first IAA International Motor Show of the post-war period. There were many good reasons for going down this route, but it took considerable vision and acceptance of the potential risks actually to take this bold step. "With the very best of intentions, many well-meaning friends tried to warn us against the idea at that time", wrote Otto Kässbohrer some years later. "They felt it would be very difficult for us, as outsiders, to build such a vehicle, and things could very easily go wrong! Yet what some people had seen as a one-off experiment would subsequently prove to have been a turning point for the entire bus manufacturing industry", as Otto Kässbohrer wrote in his memoirs.
The principle of self-supporting construction had already been in use in aircraft and airship design for many years. As early as the 1930s, the American manufacturer Gar Wood, based in Detroit, had been building buses with self-supporting bodies and rear-mounted engines, which were built under licence in Europe by the French company Isobloc. In Germany, the idea of self-supporting construction was picked up after the war by several notable manufacturers of the day, but none of these companies achieved the customer acceptance that would bring them profit, nor the international recognition and success of the Setra. Ultimately, the long years of expertise in responding to the requirements of customers, and the better quality, were what made the difference.
Otto Kässbohrer had seen clearly that the only way to meet the growing demand for buses and coaches in the long term was through production on an industrial scale. The technical anachronism of using the same design of chassis whether the vehicle was going to carry goods or passengers, which had to be modified by hand in order to turn it into a bus, was simply no longer a viable proposition. It was an impasse that would have severely restricted the scope of future developments in bus technology. Customers were demanding, with good right, that a bus should deliver the same ride quality as a passenger car. Expectations such as these were met in full by the Setra, right from the very first bus produced. Today's state-of-the-art Setra touring coaches offer the standard of comfort as is found in a luxury-class passenger car, without any compromises.
Setra S 8: a sensation in the bus industry
The self-supporting framework of the Setra, constructed out of welded square tubes, allowed Kässbohrer to kill several birds with one stone, metaphorically speaking: since the body no longer needed to be individually adapted to fit each chassis, buses could now be manufactured on a large scale. The framework construction, reinforced by diagonal struts, proved more stable than a conventional bus body shell. Its low weight brought advantages in terms of payload, performance and consumption. The first Setra weighed a mere five tonnes, with a maximum payload of 3.7 tonnes. Its fuel consumption over 100 kilometres of long-distance operation was 19 litres, while in first gear it could cope with 30 percent inclines. It had a 5-metre wheelbase and a turning circle of 17.5 metres. The favourable weight distribution that resulted from its rear-mounted engine, in conjunction with a carefully matched suspension, resulted in exceptionally good ride quality. This coach was a technical marvel for its time and its numerous intelligent design solutions caused a sensation in the bus and coach industry.
Mounted in the rear was a six-cylinder 512 DG Henschel engine with a displacement of 5.43 litres, which delivered its output of 70 kW at 2400 rpm straight to the rear axle by means of a relatively short propshaft. In order to provide sufficient space for the engine, Setra buses had a curved rear section equipped with a broad flap that gave easy access to the engine for maintenance purposes. This also brought the bus much closer in design terms to the aerodynamic ideal of the teardrop shape. To improve its Cd value even further, the underbody was clad with smooth sheet-metal panels that could be easily removed if necessary. The Setra was thus able to reach a top speed of 86 km/h. Trendsetting safety aspects were very important for bus manufacturers even back then. The first Setra, for instance, featured compressed-air brakes on all four wheels (internal expanding brakes with an engine-powered air compressor) and an engine brake as standard, as well as the usual hand brake.
The radiator grille at the front supplied the most advanced bus heating and ventilation system of its time with fresh air. This flowed through a centre channel and from there – warmed by the engine coolant if necessary – into separate side channels, from where it was distributed evenly throughout the passenger compartment from underneath the seats. Another innovative feature was a new type of blower which defrosted the front windscreens in next to no time. Rubber engine mountings helped to minimise vibration. Small wheel arches and generously spaced seat rows ensured that passengers did not feel cramped. A standing height of 1.92 metres in the centre aisle allowed for good freedom of movement.
Inspired by legislation: Kässbohrer built Europe's first articulated bus
When legislation banning buses with trailer units was passed in 1951, in the early days of the Federal Republic of Germany, Kässbohrer lost a significant product segment and the bus manufacturing industry was left facing a new challenge. Finding themselves suddenly without the large-capacity vehicles needed to cope with the growing demands placed upon them, the transport authorities were pressing for an alternative. This situation gave rise to the development of the articulated bus, a concept that was completely unknown at that point. Kässbohrer was able to call upon the considerable know-how acquired over the course of its long tradition of manufacturing large-capacity semitrailer buses for use with tractor units.
The basic concept for an articulated bus with concertina bellows and an articulated joint, which is still valid today, was defined by Kässbohrer, who also played a decisive role in its further development. Indeed, Europe's first articulated bus was a Kässbohrer. A two-axle MAN MKN 26 motorised unit and a two-axle trailer car developed by Kässbohrer formed the basis of this precursor of all articulated buses. It had one two-leaf door in the front section, a second to the rear of the bellows and a third behind the rear axle. In producing this 17.5-metre-long vehicle with four axles, Kässbohrer had to face the risk that it would not be approved for registration. This was however "provisionally" granted after a series of test drives. Following a longer period of operation in Ulm and Dortmund, the first vehicles received such glowing reports from the cities' municipal transport authorities that full approval was granted. The articulated bus, an essential component of today's local public transport services, was thus born, almost 60 years ago, thanks to Kässbohrer's initiative. By 1959, Europe's first self-supporting articulated bus, the Setra SG 165, was on the market.
Five bus model series in 50 years
In the 60 years that followed the launch of the Setra S 8, the long-established, Ulm-based company brought out a total of five bus model series, suggesting an average production span for each model series of at least ten years. The first model series was built for even longer than this, until 1967. This was followed from 1967 by the model series 100 and in 1976 by the 200 series. The 300 model series was launched in 1991, while the anniversary year 2001 (50 years of Setra) saw the premiere of the TopClass 400. This series was extended with the addition of the ComfortClass 400 touring coaches in 2004. New MultiClass 400 rural regular-service buses followed in 2005, while the low-floor S 415 NF made its debut in 2006, a year in which the IAA commercial vehicle show was held. The next generation, the model series 500, will follow in the not too distant future.
The model series 10 – premiere for outward swinging doors
The model series 10 comprised the models S 6, S 7, S 8, S 9, S 10, S 11, S 12, S 14 and S 15. The S 10 to S 14 models were available in different versions for touring coaches, rural regular-service buses or urban buses. Also included here were the first regular-service buses with the three-digit nomenclature ST 110 (a further development of the Setra Pekol) and Europe's first self-supporting articulated bus, the Setra SG 165. All in all, 7441 vehicles were built (excluding the Setra Pekol regular-service buses). At the IAA in Frankfurt in 1953 Kässbohrer presented two versions of the next Setra model: at 55 centimetres longer than the S 8, the new arrival could accommodate ten rows of seats behind the driver and front passenger as a regular-service bus, and nine rows in the more comfort-oriented touring coach version. This model series also saw the introduction of an important new feature: the recently patented, pneumatically operated Kässbohrer outward-swinging door celebrated its premiere here for use on regular-service buses. The new Setra buses initially bore the model designations S 9 and
S 10, but became a uniform S 10 a year later. The 10.65-metre-long S 11 launched in 1955, again at the IAA in Frankfurt, offered yet another row of seats. It had a wheelbase of 5.25 metres but was otherwise very similar to its smaller sibling, the S 10. The new six-cylinder Henschel 522DPK engines, used from then on in all three models, had an output of 92 kW.
Little gem: the Setra S 6 compact bus
At the Geneva Motor Show of 1955, Kässbohrer presented another new Setra product that attracted a lot of attention at the time: the compact S 6, a complementary smaller model in the first Setra model series. In technical terms, the Setra S 6 was quite radical: 6.70 m long and 2.25 m wide. The most spectacular thing about this compact bus was undoubtedly that it had independent suspension on all wheels, with swing axles front and rear. This principle involved two axle carriers joined to the body structure, to which two wishbone control arms were attached. It was a design which, for the first time, provided a bus with many of the key characteristics of modern automobile construction in terms of road holding and comfort. Rubber suspension with telescopic shock absorbers, a low unsprung weight, lower centre of gravity and the particular ratio between its wheelbase (3.50 m), overhang (3.5 m) and track width (1.85 m, and 1.7 m at the rear due to the twin tyres), gave the S 6 extremely safe road holding capability. The hydraulic dual-circuit internal expanding brake system, together with the additional ZF engine brake, enhanced the excellent handling safety of the S 6.
The block-built engine unit, which had no propshaft but instead transmitted power directly to the rear axle gear unit, represented a sensational innovation in bus engineering at that time. It was only at Otto Kässbohrer's insistence that Henschel had built the four-cylinder D 571-4 K diesel engine (the K standing for Kässbohrer), a very different proposition from the petrol engines then normally used in small buses of this type. To begin with, the engines had an output volume of 63 kW, increased later to 66 kW and then to a turbocharged 74 kW. A further similarity shared with passenger cars was the steering wheel gearshift. The outer shell of the S 6 was made of aluminium and the skylights of plexiglass. The glazing panels were now manufactured by Kässbohrer in-house, while the driver's seating area and the control elements for heating and ventilation had also undergone further development.
The light Setra compact bus, with a turning circle of just 13.4 metres that made it extremely manoeuvrable, soon convinced customers: basically, there was nothing else on the market that could compete with it. By the time production came to an end in 1964, a total of 1169 units had been built, of which there are still around 20 in Europe that are registered as buses. The design of the S 6 still evokes unreserved nostalgia and has somehow never grown "old". A few examples have been converted into motor homes and are still being lovingly looked after by classic vehicle enthusiasts.
Lightweight urban bus developed by Otto Kässbohrer together with Pekol, Oldenburg
Theodor Pekol, from the German city of Oldenburg, was also a pioneer of bus manufacturing, and had been experimenting with rear-mounted engines and self-supporting construction techniques as far back as the 1930s. It was only a matter of time before this inventive bus manufacturer from northern Germany and Otto Kässbohrer, from Ulm in the south, would get together. Pekol was working at the time with horizontally mounted rear engines, light aluminium shells and independent wheel suspension, which meant that the height of the vehicle floor was just 50 centimetres, a sensationally low figure at that time. The Setra, on the other hand, had a better steering system as well as its patented pneumatic outward-swinging doors. Otto Kässbohrer and Theodor Pekol joined forces in 1957 to develop the Setra-Pekol, or SP for short. It was built using lightweight construction techniques and, at 11 metres in length, weighed just 6000 kg but could carry a maximum permissible payload of 7500 kg. It had space for between 110 and 115 passengers, with 40 seats and standing room for 75. Kässbohrer introduced the SPL variant, a metre longer and accommodating up to 110 passengers, two years later. Air suspension on all axles was available as an option on this model. With the ST 110 of 1958, another 15 centimetres longer and also carrying 110 passengers, air suspension became standard.
The Setra S 125, which went into series production in late 1964, revealed the next stage in the development of this urban regular-service bus. The body shell of the S 125 was no longer constructed out of aluminium annular frame members with riveted alloy sheeting but, like all other Setra buses, of a self-supporting lattice framework. Here again, the 8.1-tonne payload of the S 125 was higher than its tare weight of 7.1 tonnes. Kässbohrer had also simplified the construction in a variety of other ways. Independent suspension remained for the front wheels, but the rear wheels now sat in pairs on a single rigid axle. The 97 kW six-cylinder engine was vertically mounted in the rear. The seating area now extended right back to the rear windscreen, because the floor behind the rear door had been raised by two steps. At 10.65 metres long, the S 125 provided space for 125 passengers. Also available were a 12-metre-long S 125 ÜL rural-service bus (ÜL = Überland = overland) and the articulated SG 175 at 16.7 metres in length.
The leap across the big pond
In 1955 Kässbohrer received an unusual commission: in its search for fast, spacious and comfortable touring coaches, the US bus operator Continental Trailways had come across the Ulm company. Otto Kässbohrer would later write: "This super-Setra project gave us the very special opportunity to develop a bus model that did not exist at all in Europe at that time." 200 units of the three-axle "Silver Eagle" model, 12.20 metres long, were supplied. This would go on to be developed as the "Golden Eagle", a four-axle articulated unit: the first-ever articulated bus in the US. The "Golden Eagle" was 3.80 metres high, 2.50 metres wide and 18.30 metres long.
1959: the first modular system
The modular principle of construction started to become popular in the European automotive industry during the 1970s – parts strategies, standardised engineering processes and working methods – and to be recognised as an effective way of bringing about rationalisation. Kässbohrer was streets ahead in this respect, for the building of more and more fully equipped buses, which had started with the manufacture of Setra buses, had also brought excellent opportunities to experiment with new ways of doing things along the whole product creation chain. The process had brought many positive results throughout this medium-sized company, affecting aspects such as production methods, manufacturing sequence, warehousing and even internal transport systems. Up to 80 percent of the components for the six models (S 6, S 8, S 10, S 11, S 12 and SP/ST 110) were the same at that period and would also be used in the subsequent S 14 and S 15 models of 1961 and 1965 respectively. The main differences concerned engines, transmissions, axles and tyres. The Setra modular system was a completely new departure and unmatched anywhere in the European bus industry. The concept of modular construction is realised today through an international co-ordinated production and development system that works on the basis of a sophisticated strategy of common parts.
Thanks to this well thought-out modular principle it was possible to rationalise the vehicle production process, leading to a daily production of up to four Setra buses. The benefits were clear and were immediately recognised by customers: it simplified the storage of parts for the bus operators, so making their fleets much more cost-effective to run. There were also advantages for vehicle crews and workshop personnel, as they only needed to familiarise themselves with one basic model in order to understand the other models just as well. This in turn led to the financially interesting result of reduced servicing and repair times.
Similarly ahead of its time was the Setra S 12 high-deck touring coach, 3.20 metres high and 11.90 metres long. Inspired by their experience with the US vehicles built for Continental Trailways, the team in Ulm sought new solutions for the luxury touring coach segment in Europe. A hitherto unknown level of comfort was achieved with air suspension for the individual front-wheel suspension system and a combination of leaf and air suspension for the rear. The seats on either side were fitted to rails on a raised platform running the full length of the vehicle above the height of the wheel arches, making them individually adjustable.
A further model was added to this series in 1961 in the form of the S 14, which reached the maximum legally permissible overall length of 12 metres. The even steeper rake of its front and rear sections meant that 14 rows of seats could be installed behind the driver. The huge, curved front windscreen now reached almost to roof level and was only divided by a very narrow central bar. The other models soon also adopted this new design and gained space in the process, so that the S 9 could stay the same length and mutate into the S 10, the S 10 into the S 11 and the S 11 into the S 12. This was undoubtedly the period during which the reputation of Setra buses as the most exceptional buses and coaches around was established with the industry and with drivers: one which has been maintained over many decades. Beautiful, more beautiful, most beautiful: a predicate that remains true of every model series to date.
1965: a whole new look
Pioneering bus manufacturer Otto Kässbohrer initiated the construction of the Setra
S 15 in 1965 in order to take advantage of the maximum permissible 12-metre length for a bus. Taking advantage of the full 12 metres allowed, it had space for an additional row of seats compared with the S 14, which was the same length. To achieve this, the rake of the front end was made even steeper, while the rear end was practically vertical. The trendsetting appearance of the S 15 was, in essence, a precursor of bus design as we generally know it today, and marked the beginning of a significant period of change. In the Setra, space therefore had to be made underneath the last row of seats for a horizontally mounted 141 kW six-cylinder 520 G-K Henschel engine, with the effect that every last centimetre of the passenger compartment could be utilised. This extremely spacious touring coach made it very obvious that the older models no longer represented the ideal in terms of their use of space. This was also true of the compact S 6, which Kässbohrer discontinued in 1964 after nine years in production. It was replaced in 1965 by the new S 7, which already displayed some of the key features that would characterise the next generation of Setra buses that followed two years later.
At 7.67 metres almost a metre longer than the S 6, the S 7 could accommodate an extra row of seats without any difficulty. The difference here was more a matter of the vehicle's shape: higher, straighter, boxier, which was generally the way that buses had changed in appearance between 1955 and 1965. With its width modified to 2.30 metres to meet new regulations in Switzerland, the S 7 grew an extra 28 centimetres in height compared with its predecessor, to 2.90 metres. This brought benefits in terms both of internal standing height and in its panoramic qualities.
This did however present the engineers with some difficulties in accommodating the drive system. The six-cylinder 522 FVT-K Henschel engine – again a special Kässbohrer version – was mounted vertically at the rear and delivered an output of 97 kW. In this instance the engineers had opted for a rigid axle with cardan-shaft drive. The cardan shaft passed first over the rear axle, with power delivered to the axle via a redirected transmission. This solution did not, however, leave space for a rear door, so the second door had to be positioned in front of the rear axle. This was one of the reasons why the S 7, after just three years, had to make way for the improved Setra
S 80 model.
Boxy bedfellows: the model series 100
The S 7's boxy shape and deep windows reaching right up to the roof all round had already determined the exterior design of the model series 100, launched in 1967. Only the front radiator grille, which gives every vehicle its characteristic look, needed redefining. This element was made up of a broad grille positioned between horizontal rectangular headlamps, so emphasising the vehicle's width. In the centre was the "K in a ring" Kässbohrer trademark, while clear for all to see above the grille was the name: SETRA.
Forerunners, to a certain extent, of the very successful model series 100, were a pair of stepped-floor high-deck buses, 14 metres long and 3.65 metres high, built for two Austrian companies. With its distinctive bright gold livery and a passenger area that rose in two steps towards the rear, together with extra-high windows, the Setra panoramic bus signalled that this was travel in its finest form. Seating 56 passengers on comfortable reclining seats, these vehicles offered the added comfort and convenience of air conditioning, a galley kitchen, washroom and toilet.
The model series 100, comprising the five models S 100, S 110, S 120, S 130 and
S 150, was launched in the autumn of 1967, again against the backdrop of an IAA show. All the new models were built according to the modular system and shared numerous common parts. They heralded a whole new era in bus manufacturing. The range included the 8.70-metre-long S 100, the 9.50-metre-long S 110, the 10.45‑m etre-long S 120 and the 11.27-metre-long S 130, while the top of the range was represented by the 12-metre S 150.
Kässbohrer was soon offering two different bodies for these buses. While the letter H was used from that point on to identify the high-deck touring coach body, the S 120,
S 130 and S 150 were subsequently also available in the 10 centimetre shorter versions E and P. In the E version, which found an enthusiastic customer in the German railway service, or Bundesbahn, the floor was level all the way through. In the P models, the seats were on raised platforms.
The model series 100 included all the latest technical innovations. Comfort and good road holding were ensured by the front independent suspension and the excellent leaf and rubber suspension. The S 130 and S 150 were also optionally available with air suspension. This had been improved further by using U-type rather than gaiter bellows and became part of the standard specification from 1969. A responsive hydropneumatic dual-circuit braking system brought improvements in safety and ride comfort, as did the recirculating ball power steering from ZF that was used in the S 110 model and above. Disc brakes came as standard on the front axle and were optional for the rear axle from 1973 onwards.
By 1968, it no longer took much to convert the small S 7 into a full member of the model series 100 family of buses. By extending the existing compact bus by just two centimetres to 7.69 metres and giving it a new radiator grille, it became the new Setra
S 80, with space for an additional row of seats. This small design change was also made possible by a particularly neat five-cylinder Henschel engine, for which there was now room in the rear, underneath the last row of seats. Once the S 80 was on the market Kässbohrer stopped making the S 100, of which only 142 units had been sold. Altogether 2479 units of the popular S 150 were sold, part of a grand total of 12,339 units across the full 22 models that made up the 100 series.
To complete the range, Kässbohrer then also attempted to include its urban regular-service buses in the modular system, which had long been doubly handicapped: first of all by the small numbers built and secondly by a manufacturing process that was far too complex and thus much too expensive. The 11.08-metre-long S 130 S that was launched in 1971 met most of the standard bus criteria of the German Association of Public Transport Operators (VÖV) but was in many respects a derivation of the touring coach model series. It had a boarding height of 64 centimetres and an internal standing height of 2.24 metres. The rear engine was a 132 kW vertically mounted six-cylinder unit from Henschel. The design was a success: from the very start, the S 130 S sold better than any other Setra urban bus before it.
It was followed in 1973 by the SG 180 S articulated bus, 16.88 metres long, which was also available in a rural-service version as the SG 180 Ü, with narrower doors, a full complement of seats and a higher floor. Also in 1973, Kässbohrer acted upon the recommendation from various associations that it should build a standard rural-service bus by producing the 11.78-metre-long S 140 ES, based on the urban bus but with a higher, single-level floor, underfloor luggage compartments and 177 kW Henschel engine. This was replaced in 1975 by the OM 407h Mercedes-Benz engine. With the end of the Henschel company and the ultimate integration of its activities into the then Daimler-Benz Group, most Setra customers relied instead on Mercedes-Benz diesel engines from Mannheim, which had already been proven four hundred thousand times over. Soon over 80 percent of all Setra buses would be powered by such
Mercedes-Benz power units.
Setra super-high-deck S 200: the dawn of a new era of touring coaches
With all the momentum of an idea whose time has now come, a 3.55-metre-high three-axle Setra super-high-deck S 200 set off for the Geneva motor show in January 1973. Celebrating its premiere there, it showed an international public what the touring coach of the future would look like. With its aerodynamic lines, numerous innovative details in terms of both engineering and comfort – a lower-deck galley, toilet and spacious luggage compartments – it announced the arrival of a new generation of comfortable Setra touring coaches. A new benchmark was also set by the 235 kW OM 403 Mercedes-Benz engine. The high floor meant that it was no problem at all to fit the 10-cylinder V-engine in the rear of the super-high-decker. In many ways, the styling of this model was similar to that of the subsequent model series 200. The high, spherically curved windscreen was still split down the middle, but the roof-high side windows broke with the earlier convention by being vulcanised onto the window uprights from the outside. A narrow mesh panel concealed along the full length of the bus between the roof and the side windows allowed the intake and extraction of air for the sophisticated ventilation and climate control system. An electronically controlled cross-flow ventilation system ensured that the fresh air was evenly distributed throughout the passenger area.
Model series 200: elegance and comfort bring renewed success
In 1976 – the Setra brand was 25 years old – came the next big step. In this, its anniversary year, the Ulm company launched the new model series 200 with six models in all: the high-floor buses (H) S 211 H, S 212 H, S 213 H and S 215 H, all of which were 3090 millimetres high, and the two high-deck models (HD) S 213 HD and S 215 HD at 3340 millimetres, were all premiered at this time. Key design elements here were the one-piece spherically curved front windscreen and the flat bonded side windows. In these luxury touring coaches, cross-flow ventilation was already taken for granted. Both drivers and passengers in the 200 series of buses benefited from their excellent road holding and suspension. The independent front suspension as well as the rigid rear axle now included air suspension, while a maintenance-free regulating valve kept the bus at the same height irrespective of load.
Over the 25 years between 1951 and 1976, 20,000 Setra buses had been delivered to customers. It says a lot for the model series 200 that it only took another ten years to double this figure. In fact, a total of 27,680 units of the 26 models that made up the 200 series were sold.
High and mighty: super-high-deck and double-decker touring coaches
At the IAA of 1979 Setra introduced a surprise, in the form of a super-high-deck articulated bus, the SG 221 HDS. In this model, the driver and front-seat passenger were repositioned underneath the passenger deck, so freeing up space for an additional row of seats. From this prototype was derived the S 216 HDS, with its striking lower-deck cockpit. The exterior dimensions of the S 216 HDS and the S 215 HDS were in each case 12 metres long and 3.63 metres high. The S 215 HDS, however, had a conventional driver's seat and thus one fewer rows of seats. Three axles gave these vehicles extensive luggage compartments and the potential for all sorts of added comfort and convenience features. When it came to luxury travel, the sky was the limit in these super-high-deck touring coaches. For many bus operators, the S 216 HDS in particular became the absolute flagship of the fleet.
The real-life experience gained with the HDS models ultimately served to prove that the design concept behind the 200 series practically predestined it to become the basis for the development of a Setra doubledecker bus. Many tried and tested components from the standard product range could be integrated into the S 228 DT. The Setra S 228 DT represented, in all its key characteristics, the true top of the range of this successful model series.
This was ultimately also confirmed by sales of 1104 units of this model, which was built between 1982 and 1993. The record year was 1991, when 168 S 228 DT coaches were sold. The four metre-high luxury touring coach with two passenger decks proved a success not only in Germany, but was also much in demand for export. England, Sweden, Norway, Denmark, France, Switzerland, Italy and Austria, and even tiny San Marino, all took delivery of Setra doubledecker coaches.
The company's success was rooted in the economical and efficient way Setra buses and coaches were built. For customers this brought the added benefit of an advantageous purchase price, delivering a very favourable cost-benefit ratio, especially in terms of the number of seats as well as personnel and fixed costs. The S 228 DT also stood out for the timeless elegance of its design, which reflected lasting value and functionality. This styling and the aerodynamic front section – particularly significant on a vehicle of this size – without obstructive roof projections or superstructures, soon came to represent the trademark look of the Setra S 228 DT. For many companies, this made the acquisition of this large-capacity touring coach a possibility. As an attractive-looking flagship, it was also the best possible advertisement for coach travel. The
S 228 DT stood for good quality travel, excellent handling, a high standard of safety and a comfortable ride.
New three-axle model for the US and Europe
A new foray into the US market – after the "Silver Eagle" and "Golden Eagle" - began for the Ulm company in 1984 with the introduction of the super-high-deck S 215 HDH with its fifteen rows of seats. The vehicle was equipped for this new venture with Rockwell axles, Eaton transmissions and engines from Detroit Diesel. It proved extremely popular with US customers, the experts praising its combination of sophisticated European coach design and American components. Although not exactly cheap, more than 200 units of the S 215 HDH were sold in its first four years on the market.
Encouraged by this success, a version for the European market bearing the same number designation came into being in 1988. It was given the impressive-sounding name of "Transcontinental". For the American market, Kässbohrer then launched a 13.71-metre version in 1993, with a slightly shorter version appearing in Europe two years later. In those days such dimensions were far from being common in the "old" world, and in fact Setra's developments triggered a debate over permissible lengths for buses and coaches.
Setra production outside Germany for the first time
Production of Setra buses outside Germany began in 1980 in the French town of Ligny-en-Barrois (Lorraine). The ground for the Setra brand over in France had been well prepared since 1960 by Setra's first representative there, Peter Momber, known as "Monsieur Setra". After a first S 6 had found its way to the southern French town of Perpignan in 1959, two Setra buses appeared at the following year's Paris Motor Show. A subsidiary company was established in 1966, moving to a large, new 42,000 m2 site in Sarcelles, just north of Paris, in 1977. Today, this is also the home of EvoBus France SA and the administrative headquarters of both brands in France, which is their biggest market in Europe outside Germany.
French manufacturers were not particularly impressed when the first S 130 S and SG 180 urban buses were delivered from Ulm to the port city of Brest in western France (Brittany). In order to quell their agitation, the suggestion was made by French politicians that, in order to safeguard jobs, Setra buses should in future be built in their own country. A suitable site was ultimately located in the eastern region of Lorraine, where Kässbohrer invested in buildings and a new production facility, where regular operations began in 1981. From the very first day and for a full 15 years, throughout the important integration phase for the Setra brand ("Le Setra qui vient de France"), the plant was headed up by a Swiss, Jean Lendenmann, who had previously been a Setra bus sales executive in France. In the meantime, nearly 10,000 Setra buses and coaches have been built in Ligny for customers in France and throughout Western Europe. The plant today is a key element in the EvoBus co-ordinated production system, producing primarily Mercedes-Benz regular-service buses for the French market and Mercedes-Benz minibuses.
New in Europe: ABS as standard on all buses
Kässbohrer once again justified its reputation as an innovative motor vehicle manufacturer in 1984: with the interests of passenger safety always a priority, the company had begun work on an anti-lock braking system as far back as 1970. The available sensors, electronic components and pressure control valves of the day, however, had not proved precise enough. Ten years of intensive trials were to follow before the company was able, in 1982, to introduce a braking system developed in cooperation with Bosch that would from that point on be available for all Setra buses. But safety should not be an optional extra: in 1984, Kässbohrer became the first commercial vehicle manufacturer in Europe to equip all its buses as standard with an anti-lock braking system (ABS).
Innovative concepts for both urban and rural transport services
All good things are worth waiting for: Kässbohrer relied until 1984 on the 100 model series for its regular-service buses. At this point, however, the urban and rural-service buses caught up with all the latest engineering features of the model series 200, with numerous components from the 200 touring coach series being adopted in their production. The first to come onto the market was the S 215 UL rural-service bus. The Ulm company was unable to build a standard rural regular-service bus, abbreviated in German as "STÜLB", because the engine manufacturers refused to supply the necessary engines. But the generous front and rear windows, driver's window and glass doors of Setra's own subsequent interpretation of the rural regular-service bus nevertheless meet the recommendations of the determining STÜLB authority, as do its driver's workstation and electrical systems. The necessary power plants for these vehicles did then become available from the two engine suppliers concerned without any problem.
The "Regional" rural-service bus was differentiated from the S 215 RL "Rational" urban regular-service bus already being built at that time by its lower central aisle and smaller engine, and by seats that were raised on side platforms. This was also true of the
S 215 SL "Communal" urban bus, launched in 1984, in which the absence of load compartments meant that the floor height could be lowered. From 1985 on, this bus was also available with a level floor. The S 215 SL was fitted for the first time with inward-swinging doors, while the destination indicator boards on the side and rear were integrated into the vertical roof edge. The new regular-service buses were to prove a great success: around 1000 units were built by Kässbohrer in just the first two years. At the same time as the twelve-metre models, a new generation of articulated buses also came into being. With these, the Ulm bus manufacturers once again ventured something new: the 18‑metre-long articulated regular rural-service bus SG 221 UL and its 17.42‑m etre-long urban counterpart, the SG 219 SL, were designed for the first time as articulated pusher buses.
And there was a further innovation from Ulm: the S 215 NR was Europe's first low-floor bus for rural regular-service use. This was the first rural regular-service bus to adopt the principle of stepless entry and to feature a level floor between the front and middle doors. At a height of 3.09 metres it had an impressive turning circle of just 21.70 metres and, despite its low-floor design, the standard of comfort typical of any Setra. The one-off model S 217 NR, a 13.34-metre-long, three-axle rural regular-service bus, remained on the other hand a demonstration object only. It was used to lobby for new directives on bus length under the name "Project Europa" and provided valuable input on what is now everyday reality for all buses more than 12 metres long.
A new production plant for a new model series
Over the years, it had become increasingly clear to the shareholders and directors of the Karl Kässbohrer Fahrzeugwerke company that a new bus assembly plant was needed. In 1982 the company therefore purchased a site of some 250,000 m2 on the "Pfuhler Ried" industrial area in Neu-Ulm, where initially, from 1989, a new central parts warehouse was built. Work began the following year on the construction of a 40,000 m2 assembly plant, where the new model series 300 went into production in the autumn of 1991. Kässbohrer invested 130 million German marks in this whole facility, which was designed for an annual capacity of 3000 buses and coaches.
Flying into the future with bug antennae and wings: model series 300
Kässbohrer ventured its first impressive steps into the future of bus and coach manufacturing in early September 1991 - Setra's 40th anniversary year - with a range of, initially, three models. In a spectacular show in the Donauhalle in Ulm, a 12‑metre-long touring high-decker, the 315 HD, the 3.75‑m etre-high super-high-deck S 315 HDH and the 8.87‑metre-long 33-seater S 309 HD were launched to customers and industry specialists. Compared with their predecessors, the high-deckers had grown in height by 18 centimetres, the super-high-deckers by 12 centimetres. A completely new era of luxury bus and coach travel had well and truly arrived.
The series 300 was in all respects quite new, and stunning to look at. Among its, at that point, completely new design and comfort features were an all-round glass cockpit and a driver's workplace designed according to the very latest ergonomic thinking. The side panelling ran in an elegant, spherical sweep from the top of the front windscreen to the slightly raked B-pillar cladding, which separated the driver's area from the passenger section. Projecting forward from the front corners were new-style (and initially frequently mocked) "bug antenna" exterior mirrors, now long seen as representing the state of the art.
Right from the start, ergonomic considerations had been behind the design of the driver's workplace. The front panel, headlamp and grille section, together with the bumper, formed a clear pattern of three horizontal lines that appeared to lean slightly forward. Visibility to the side of the vehicle was also good, thanks to optimised sight lines from the side windows. At the point where the field of vision ended, the down-curving integrated mirrors took over: the slightly convex curve of the mirror glass reflected the full side section all the way to the rear of the vehicle, while smaller mirrors integrated into the angled section brought the front edges of the vehicle clearly into perspective. The driver had a Recaro sports seat and a height- as well as rake-adjustable steering wheel. Speedometer and rev counter were positioned in clear view on the dashboard. A display in six languages showed the most important vehicle data – a new system that made maintenance so much simpler. Behind it sat the most sophisticated electronics ever seen in a bus at that time: more than 1500 cables were clustered into segments, most of which could be tested prior to assembly. These were then connected through an on-board computer, which in turn sent signals via a databus to the individual, decentralised multiplex nodes.
This meant that only one data line was now required for heating, ventilation and air conditioning rather than six, as hitherto. This one on its own, however, was far more effective than the six that had been needed until then. A "vario drive" system maintained the functionality of the air conditioning compressor, so ensuring that both driver and passengers could keep a cool head even at low engine speeds, for example in traffic jams. A new automatic temperature control system (ATC) governed the heat exchangers in the roof ducts. It did so with the help of the rotary blowers from the tried and tested cross-flow ventilation system, which blew fresh air into the interior through the mesh roof and individually adjustable vents.
Only the best was good enough for the 300 model series when it came to safety too. Anti-lock brakes and acceleration skid control (ABS/ASR) were part of the standard specification, as were a Telma or Voith retarder. The broader track width gave the bus better road holding, while double shock absorbers ensured optimum comfort. The Mercedes-Benz engines met the Euro 1 emissions standard: the OM 442 LA in the
S 309 HD delivered an output of 213 kW and the S 315 HD was equipped with a 280 kW turbocharged V8 OM 442 LA engine.
The innovative measures introduced in the Setra 300 model series, and the way it re-interpreted the concept of the high-quality touring coach, soon convinced the industry experts: a year after its launch, the S 315 HD beat the competition by a clear margin to take the coveted title "Coach of the Year 1992", awarded in the Dutch city of Maastricht by Europe's specialist bus journalists.
New doubledecker with a family resemblance
At Europe's largest specialist bus show "Busworld", held in the Belgian city of Kortrijk in October 1993, Kässbohrer launched its new flagship model, the Setra S 328 DT. More than 1100 units of the previous doubledecker model S 228 DT had been sold. The distinctive curving strake along on its side made the S 328 DT immediately recognisable as a member of the 300 series family. The second door was located just in front of the first rear axle, with the load compartment beginning just behind that. As had been the case in its predecessor, it had 58 passenger seats spread over two decks. The upper deck was 1.80 metres high, the lower one 1.68 metres, with a spacious club seating area at the back. The front axle, the axle load of which had been increased to 7.5 tonnes, was fitted with pneumatic disc brakes. The turning circle, at 20.48 metres, was impressively tight. Its power came from a 385 kW V8
Mercedes-Benz engine mounted in the rear.
Dual-purpose and rural-service buses built from the same modular system
The transition to the new model series continued, with the addition of further new models to the range. At the IAA of 1994, the new generation of Setra rural regular-service buses was the focus of industry specialists' attention. The Ulm engineers had managed to conjure three different versions from the basic 12-metre chassis: the
S 315 H with 55 seats and the S 315 UL, with a maximum of 53 seats. While the steeply raked front windscreen identified both of these as typical examples of the rural regular-service model, the inclined windscreen of the third model in the trio, the economical, dual-purpose 51-seater S 315 GT, betrayed its clear relationship to the Setra touring coaches. Six months before EvoBus was formed, the Ulm bus development team thus presented some striking credentials as a new Group brand.
The 11.32‑metre-long S 313 UL followed a year later, together with the articulated
SG 321 UL, available with either 69 or 77 passenger seats. The new articulation joint was particularly special, for its separate pitch and pivot axes and vibration-damped slewing ring allowed an articulation angle of 52 degrees. The "Kurvenstar", or "King of the curves" – as it was called in the company's advertising – thus had a turning circle of just 23 metres. Hydraulic multi-disc brakes ensured reliable co-ordination of movement between the front section and the trailing unit. And, to top it all, it had luggage compartments that made it suitable for excursion travel.
The company Karl Kässbohrer Fahrzeugwerke GmbH reached its centenary in 1993. But the scale of the company's financial difficulties could no longer be ignored and, ultimately, there were no grand celebrations to mark this milestone in the company's history. Intensive development activities in the bus and coach sector became a more or less visible struggle to keep pace with the market and to show that Setra buses and coaches were among the technologically most advanced and here to stay. The vehicles of the model series 300 represented the physical embodiment of these company values and, as such, were still an interesting and even attractive proposition for many European competitors. A new future, in business terms, for the time-honoured Ulm brand was determined on 14 February 1995, when the European Union in Brussels gave a green light to the proposed merger of the two most well-known names in bus manufacturing in Germany and Europe: henceforth the trademarks of the three-pointed Mercedes-Benz star and the "K in a ring" of Kässbohrer on Setra buses and coaches would become the (brand) pillars of the newly formed company EvoBus GmbH, Stuttgart.
Bus of the Year 1996: the S 315 NF rural regular-service bus
Development work on the new Setra rural regular-service buses continued with the same vigour after the creation of EvoBus as it had before, if not even more so. The
S 315 NF low-floor rural regular-service bus launched in January 1996 received the "Bus of the Year" award from specialist European journalists just four months later. This was the first Setra launch since the establishment of EvoBus. Its deep side windows made the full-length low-floor design clear even from the outside: in order to remove the need for a step in the rear, the developers tilted the whole drive system by 6.5 degrees, whilst also sloping it by 3 degrees. The exceptional safety system of the
S 315 NF was also much applauded. Four cross-sectional elements acted as roll-over bars, while non-reflective instruments and the already familiar integral mirror system helped the driver to keep the overview. Disc brakes on all four wheels were part of the standard equipment, as were ABS and ASR.
New terms to define three categories of bus and coach
Three-axle versions of the touring coach, dual-purpose and rural-service models, all of them more than 12 metres in length, were added to the range in the ensuing years, contributing not insignificantly to the very favourable development of business for the Setra brand as part of EvoBus. The first of these, positioned just below the S 315 HDH, was the economical S 315 GT‑HD introduced in 1996, which proved very popular both at home and abroad. To make the full product portfolio somewhat easier to understand, the bus and coach range was divided into three categories whose names, still used today, clearly define the products in them:
  • The luxury touring coaches bear the name TopClass
  • ComfortClass stands for the economical GT and GT-HD models of touring coach, including right-hand-drive versions and
  • as a reflection of their multi-purpose functionality, the rural regular-service and straightforward dual-purpose buses are grouped together under the MultiClass name.
As early as 1994, Setra ventured into new territory as far as bus length was concerned with its prototype S 217 NR model. This was emphatically topped in 1997 with the launch of the 15-metre rural regular-service S 319 UL. With four extra rows of seats, this vehicle neatly filled the gap between the twelve-row standard bus and the articulated bus. A trailing axle developed in conjunction with ZF ensured that the turning circle could be significantly reduced. Under the name Rear Axle Steering, the system was an innovation in the bus industry worldwide and played an important part in earning acceptability for buses of up to 15 metres in length. The S 319 NF low-floor bus then also soon followed, in late 1997.
A further intermediate model in the ComfortClass was realised in 1999 in the form of the 13.85‑m etre-long S 317 GT-HD. New lengths were also introduced in the TopClass in 1997: in order to preclude potential problems with weight, the 13.65-metre S 317 HDH-3 and the S 315 HDH-3 were designed right from the start with three axles.
After more than five years of the new company's existence, the launch of the 400 series in the spring of 2001 represented a major milestone in the history of the most successful industrial cooperation in the European bus and coach industry. This new model series enabled the Setra brand to demonstrate than none of its will to innovate had been lost through integration into the Daimler group of companies. On the contrary: the availability of so many advantages, resources and synergies in motor vehicle research and development under the one roof of the largest commercial vehicle, bus and coach manufacturer in the world, provided emphatic evidence that the future of the bus industry in Neu-Ulm was safe.
The current Setra product portfolio
TopClass 400: travelling at its most luxurious
With the TopClass 400 of 2001, Setra introduced a whole new dimension in touring bus manufacture, guaranteeing travel at its most luxurious for both passenger and driver. Such standards were ensured by innovative comfort and convenience features such as back-friendly seats, multimedia systems and a versatile range of kitchen and catering equipment. The ergonomically designed cockpit is a blend of elegant functionality and good looks. A greater range of adjustment for the driver's seat, and better arrangement and accessibility of instruments, switches and levers ensure that TopClass 400 drivers can concentrate on the job in hand, thereby contributing effectively to the further safety of passengers.
It is no coincidence that the TopClass 400 was voted "Coach of the Year 2002" by a jury of European specialist journalists just eight months after its first appearance. The jury's decision was based, amongst other things, on some very impressive technical solutions and on the distinctive way the design of the bus manages to fuse form with function. As far as safety is concerned, the TopClass 400 also represents the absolute state of the art. All vehicles are fitted as standard with disc brakes, the electronic braking system (EBS), anti-lock braking system (ABS), acceleration skid control (ASR), Brake Assist (BA) and Electronic Stability Program (ESP). Setra also offers an adaptive cruise control system (ART) and Lane Assistant (SPA) as optional extras on its touring coaches.
Since its most recent update in 2007, the TopClass 400 generation has been represented by a total of seven vehicle models. The premium touring coach category includes the 10.10‑metre-long S 411 HD Club bus, the 12-metre S 415 HD, the super-high-deck S 415 HDH with three axles, the 13.19-metre S 416 HDH, also with three axles, and the 14.05-metre S 417 HDH super-high-deck model. This latter model also provides the basis for the US version with Detroit Diesel DD 13 engine, which delivers 336 kW in its most recent EPA 10 emissions standard version. The flagship of the fleet, however, is the 13.89‑metre-long doubledecker S 431 DT with charge-air cooled 350 kW OM 502 LA engine.
The ComfortClass 400 comprises nine vehicle models, including the right-hand-drive versions S 415 GT-HD and S 416 GT-HD, as well as possible additional axle configurations for the S 416 GT-HD. The impressively designed, fuel-efficient coaches in this category benefit from a completely redesigned cockpit and from numerous innovative technical features for both exterior and interior. The technical details underline the individuality of the various buses and coaches in the ComfortClass 400, whatever their length, from the S 415 GT (12.20 m), S 416 GT (13.04 m), S 415 GT-HD (12.20 m), S 416 GT-HD/2 (13.02 m), S 416 GT-HD/3 (13.02 m) and S 417 GT-HD (14.05 m), right through to the S 419 GT-HD at 14.96 m. This completely new length concept, for buses that are designed for combined touring and occasional transport use, creates noticeably more space in the interior than is found in comparable vehicles.
Depending on the length of vehicle, the bus operator can choose between three different air conditioning power units. The basic unit, mounted on the centre of the vehicle roof, is 2680 millimetres long and has a cooling capacity of 32 kW, working with six brushless double-radial evaporator blowers and four condenser blowers. It has a compressor displacement of 470 cc and is designed for use in the S 415 GT‑HD and S 416 GT-HD. The 3200‑millimetre-long "hot-climate country" version with eight double-radial evaporator blowers and five condenser blowers, has a cooling capacity of 35 kW in conjunction with an air-conditioning compressor displacement of 560 cc, and is installed as standard on the three-axle S 417 GT-HD and S 419 GT-HD models. This climate control concept ensures that all vehicle models in the ComfortClass 400 category also live up to their name in terms of heating, ventilation and air conditioning.
With nine vehicle models ranging in length from 10.81 m to 14.98 m, with two low-floor and seven normal-floor vehicle variants, the MultiClass 400 covers a broad spectrum of regular-service and occasional transport use. Used on regular-service routes during the week and for excursion travel at weekends: MultiClass 400 vehicles are remarkable in their flexibility and economic efficiency.
Low-floor buses are an essential part of any regular-service bus fleet today. Boarding heights on the S 415 NF (11.95 m), available with either two or three doors, and on the S 416 NF (13.01 m) are just 360 millimetres, assuming size 11 R 22.5 tyres all round. The doors lead directly into a stepless interior: two vehicles, designed for regular-service use with a high passenger flow and ideal for use by adults pushing a pram or pushchair or by wheelchair users. To meet varying requirements, available features include innovative cockpit variants, a variety of destination indicators and numerous different seating configurations.
The remaining seven models in this product segment represent the popular Setra rural regular-service bus range (UL). At just 10.80 metres in length, the S 412 UL is the most compact and manoeuvrable of these, while it also features the new touring coach seats launched at the IAA in 2010. Its short length makes it ideal for economical regular-service use in topographically challenging areas with narrow and steep sections of road. The remaining vehicles are the 12.20-metre S 415 UL, the S 417 UL at 14.05 metres in length and the S 419 UL, a full 14.98 metres long. Spacious luggage compartments, comfortable seats and a wide range of optional features such as a galley kitchen, toilet or various air conditioning systems, make these the ideal combination of regular-service and touring vehicle.
The introduction of the new low-floor generation of the MultiClass 400 at the IAA in Hanover in 2006 and of the two high-floor MultiClass 400 models S 415 H and S 416 H, launched at the IAA in 2010, completed the transition of the full Setra bus and coach range to the innovative model series 400. The new development of more than 20 models and variants had been completed in the space of around five years.

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