Mercedes O 305
10.07.2008 - 00:00

German version

Mercedes O 305
  • New standards for city buses
  • Design for one-man operation
  • Sound basis for a host of variants

Mercedes-Benz O 305 prototype at the Frankfurt International Motor Show, 1967.

At the 1967 Frankfurt International Motor Show, the new O 305 city bus was presented to the public for the first time; large-scale production began one year later. This ushered in a new era in bus manufacture at Daimler-Benz, with touring coaches and city buses leading separate lives from then on.

One for all
As early as 1966, the designers at Daimler-Benz had submitted the draft of a special city bus designed for one-man operation and featuring a low floor, high side windows, air suspension, compressed-air brakes and a rear-mounted engine. However, other people had put their heads together elsewhere at roughly the same time and come up with a similar concept: under the management of O.W.O. Schulz, technical director of Hamburger Hochbahn AG, a committee of the German association of local public transport operations set out to elaborate recommendations for the standardization of regular-service city buses - and presented them at the association's annual convention in 1967.

They specified an eleven-meter long bus with rear-mounted engine and a low floor at a convenient height of 725 millimeters. They also suggested double inward-folding doors in front of the front axle and the rear axle, a standardized instrument panel and a central electrics compartment. The rear screen was to be made of a non-dazzling glass and side windows had to be generously dimensioned. And finally, the interior compartment was to provide space for 41 seated and 61 standing passengers.

Mercedes-Benz O 305 production bus from November 1968.

Intentional break with tradition

The members of this committee represented some 70 percent of the German fleet of regular-service city buses - a powerful argument for the association's demands and the reason why the O 305 had to put up with certain modifications shortly before its production startup.

At the time of the launch in 1967, the fathers of the concept would never have thought it possible that more than 16,000 units of the new O 305 city bus would have come off the assembly lines by the time its career came to an end in 1985. Quite on the contrary, at the 1967 Frankfurt Motor Show, not only the new Mercedes-Benz bus but also its competitors from Büssing and Magirus were critically reviewed. Soon, the mocking reference to the "container on wheels" was passed around. Many contemporary witnesses felt that the new standardized regular-service bus with its rational rectangular shape was too drastic a break with the customary design that dated back to the 1950s and featured familiar elements such as chrome trim and chubby proportions.

Interior compartment of the Mercedes-Benz O 305, 1986.

Costs down, comfort up

But there was method in this apparent madness: the local public transport operations had come under double pressure even in those days. They had to cut costs and at the same time improve the attractiveness of local public transport which was faced with growing competition from the ever more easily affordable passenger car. Passengers were to be attracted by the low floor with convenient entry, by high ride comfort afforded by air suspension and by an unmarred panoramic view through generously dimensioned windows.

Costs had come under scrutiny mainly in three respects: the standardized regular-service city bus was to cut not only the vehicle purchase price but also the cost of servicing and repairs. Cost-cutting was also at the forefront of the design for one-man operation, whose benefits were, however, initially disputed and bestowed a so-called one-man bonus of twelve percent on many drivers. The director of the public transport authorities of Heilbronn, for instance, drew up a calculation for the district council to prove that the changeover to one-man operation would be an expensive hobby since this would prolong the time the bus spent at stops, with adverse effects on turnaround speeds and an ultimately expensive demand for additional drivers and buses.

Continuous concept development

This calculation did not work out, as can easily be read off the extraordinarily successful history of the O 305. As early as 1970, the plant presented the prototype of an inter-city bus derived from the O 305, designated O 307, which complied with the local public transport guidelines for a standardized inter-city bus. The new O 307 adopted the frame, major parts of the bodywork and the much acclaimed driver's workplace from the O 305 but differed from the latter in that it was 11.7 meters long (0.7 meters longer than the O 305) and had a 150 millimeter higher floor than the O 305.

The O 305, which had initially been available with the 8.7 liter six-cylinder OM 360/h engine with either 170 or 192 hp, in its turn inherited the 240 hp eleven-liter OM 407/h engine from the O 307 in 1973. From 1973 the O 305 was additionally available with a new three-speed automatic transmission specially developed for the bus by Daimler-Benz and supplied ex factory with or without retarder. This automatic transmission, designated W 3 D 080, was so compact that it was particularly suitable for installation in what was a notoriously small rear-end compartment.

Alternative propulsion systems

In 1977, the two-axle O 305 regular-service city bus was joined by a three-axle articulated pusher bus derived from it, the O 305 G which was 17.3 meters long and designed for a gross weight of 26 tons.

Mercedes-Benz O 305 G with modified front end, operated by the local public transport authorities in Essen, 1982.

The duo bus version DUO O3 305 G D/E was designed for being alternately operated by electrical energy from overhead lines and a diesel engine. A special version of this bus remained in service in Esslingen in Swabia for many years before it was sold by the town's local public transport authorities in 1988.

Mercedes-Benz O 305 TD DUO solo bus in regular service in Esslingen/Neckar, 1979.

Mercedes-Benz O 305 GTD DUO articulated bus in regular service in Esslingen/Neckar, 1979.

And finally, a fleet of 20 hybrid electric buses - the OE 305 - made a name for themselves by demonstrating the suitability of hybrid electric buses for everyday line service in cities. 13 of these buses did service in Stuttgart, the remaining seven in Wesel in North-Rhine Westphalia. In inner-city operation, these buses operated exclusively on electrical energy supplied by batteries; in the suburbs, by contrast, they operated in the diesel-electric mode, meaning that a low-pollutant and specially encapsulated diesel engine fed the batteries via a generator.

Mercedes-Benz OE 305 with electric drive tested by Stuttgarter Straßenbahnen AG, 1979.

Popularity around the world

Despite its compliance with the city bus guidelines defined in 1967, the O 305 was by no means a phenomenon that remained restricted to Germany. In several parts of the world, this bus, of which as many as 4,743 chassis versions were supplied, is still enjoying enormous popularity even today. Singapore, for instance, operated 200 units of the O 305.

Mercedes-Benz O 305 in Kuwait, 1975.

And as soon as the regulation to procure buses only from Commonwealth countries was abandoned in Hong Kong, the local Kowloon Motor Bus Company ordered an O 305 for testing in 1983.

This bus with a 4.5 meter high double-decker body made by Alexander left such a good impression in what was still a British crown colony at the time that another 40 units were ordered - some of these are still in operation today, having made a name for themselves as particularly safe means of transport. The O 305 buses in the streets of Hong Kong hold a very special record: there has not been a single serious accident with these vehicles in all these years.

Mercedes-Benz O305 in regular service in Baden-Baden, 1970.

Technical data - Mercedes O 305 (Type sheet)

Photos and text:
Daimler AG


gedruckt am 20.01.2022 - 06:10