Jelcz M11

MPK Lublin Jelcz M11 in Lublin, Poland in 2009

At the beginning of the 1970s, the authorities of Polish People's Republic decided to upgrade their city transport fleet.[1] For this purpose already in years 1970–1972 on Warsaw streets it have been started to test such bus models as: Hungarian Ikarus 242, West German Magirus-Deutz M170-S11H, French Berliet PR100, Italian FIAT 420A, British-Danish Leyland Lidrt 12/4 Worldmaster, Spaniard Pegaso 5023, Japanese Hino RC620 and Czechoslovak Karosa SM11.[2] The winner was Berliet PR100.[3] From the beginning this model was considered as temporary because of bigger transportation needs and it was planned to expand it by adding third door. New Jelcz PR110 was 12-meters bus provided with three doors.[4] These vehicles were being made in 50% with parts imported from France.[5]

The crisis of the 1980s meant that Polish People's Republic government didn't have foreign currency to buy parts for these vehicles. Parts imported from abroad for one bus by prices from the beginning of 1984 costed 2000 US dollars. They couldn't be bought in Polish factories. In addition, the WSK Mielec engine factory could produce only up to 1,000 engines per year.[5] Because of this it has been decided to start cooperation with Hungarian People's Republic. Trade agreement between Poland and Hungary signed in Warsaw 24 October 1983 assumed deliveries to Polish cities Ikarus 260 buses[6] and Csepel 260.88 chasis (which were used inter alia in Ikarus 260 buses).[7] In return, the Hungarian side was receiving Polish Fiat 125p's i 126p and Star trucks.[8] According to the agreement Hungarian People's Republic had to deliver in years 1986–1990 about 1500 complete chasis with driving system. Even then, it was found that Jelcz M11's (initially named Jelcz M110) were supposed to be a temporary solution and their production should be finished at the moment of appearance Jelcz M120's, produced by Polish industry at all.[5] Problems with exploitation and failure rate of Jelcz M11's accelerated working on new models.[7]

New Jelcz M11 bus was based on Csepel chasis plate with the engine. Body was taken after little modifications from Jelcz PR110. First prototype was made in 1983. During tests in Budapest scientists from the local polytechnic did computer endurance tests of structural elements. Serial production of Jelcz M11's began in 1984. New buses were being produced parallelly with Jelcz PR110's, and till 1986 even with Jelcz 043. In 1990 production of M11 has been finished; about 2600 buses had been produced.[9]

KM Głogów Jelcz M11 rear in Głogów, Poland in June 2005

Jelcz M11's were placed to all city transport operators (every except Warsaw) from country distribution. To the Warsaw Jelcz M11's went in 90. years, where they were being mainly exploitated by private operators.[10]

In 1994 there have been created plans to adjust city buses to the needs of people with physical disabilities. For this purpose, expertise has been done, which concluded that the buses Jelcz M11, as well as based on the same floor plate Ikarus 260s/280s, are not suitable for fitting elevators. Where as building folding ramps was excluded because of too high floor plate. Because of this conception of building new buses have been created, even though partly low-floor, instead try to modernise current buses like western companies.[11]

Ikarus 260

Jelcz M11's were equipped with Hungarian chassis Csepel 260.88.[7] The same chassis plates were being used in Ikarus 260 buses. The vehicles were characterized by high flat floor.[5] Chassis plate was the reason of most defects of Jelcz M11 but it allowed the exchange of engine parts between Jelcz M11 and Ikarus 260s and 280s.[7]

The bus was powered by six-cylinder in-line diesel engine RABA-MAN D2156HMU6 of a capacity 10350 cm³ and maximum power of 193 HP. The drive unit allowed achieve a maximum speed of 82 km/h. It was lower value than in Ikarus 260, Jelcz was supposed to be – contrary to the Hungarian bus – typical urban vehicle.[5] Engine was located horizontally in the middle part of floor plate.[7]

Power was transferred by 5-speed manual gearbox typu Csepel ASH 75.2. From the gearbox the power of engine was transferred by the driveshaft (Gewes production). Driveshaft drove the rear axle of the company Raba. In the bus was used rear axle RABA 118, newer than in Ikarus 260.[5]