Jelcz M121MB #110

History of bus Jelcz M121

The row of decommissioned Jelcz buses at the former depot at Grabiszyńska street

The history of the Jelcz M121M bus begins in the 1970s, when first the Berliet PR100, and then its Polish counterpart Jelcz PR110, were built. On its basis, the first Polish construction of a low-floor bus was created. The first bus assembled in Poland having a partially low floor was the Scania 113 CN MaxCi. Its production started in 1994 in Słupsk. In the same year, the industrial assembly of the low-floor Mercedes O405N began. The appearance of these vehicles made Polish constructors realize that the idea of creating a disabled-friendly bus was completely ignored. Therefore, after breaking off cooperation with the Volvo concern, work began in Jelcz on a design of a Polish bus with a low floor.

The interior of Jelcz M121 bus

In October 1994, a prototype was presented in Jelcz, marked with the symbol MN120M, later known as the M121M bus with the rolling stock number #9501. The bus was 11,920 mm long, 2,500 mm wide and 3,021 mm high (19 mm less than Jelcz 120M). It had three pairs of two-leaf doors, pneumatically controlled and arranged in a 2-2-2 system. It could accommodate a total of 100 passengers, including 34 seated. The bus was equipped with the MAN D0826 LUH engine, used since 1993 in the Jelcz 120MM/1 model, with a maximum power of 230 HP, meeting Euro-1 standards. The unit worked with a ZF 4 HP500 four-speed automatic transmission. The curb weight of the vehicle was 9,800 kg, while the total weight was 17,500 kg. Jelcz MN120M was equipped with a pneumatic, dual-circuit braking system with parking and emergency brakes and power steering.

The new bus was a low-entry construction (term used in 1994), but with two transverse steps in the centre of the vehicle. In the year of the premiere, these two steps did not interfere at all, as there were really few completely low-floor buses on the market. However, ten years later, such a structure was considered extremely obsolete. The low floor effect was achieved by redesigning the truss and the use of the Jelcz 65N rigid portal front axle and low-profile tubeless tires. Behind the middle doors, in the interior there were two steps, which allowed to keep the basic structure of the Jelcz 120M bus, i.e. the Jelcz 1032A drive axle and the horizontal location of the engine on the rear overhang. The floor height in the front and middle doors reached 370 mm (for comparison, in Jelcz 120M these were 642/712 mm, respectively). Meanwhile, in the entrance on the rear overhang, there were two steps and the height of the floor was 936 mm (in Jelcz 120M – 955 mm). In Jelcz MN120M, pneumatic suspension of both axles was used, equipped with the ECAS system, which allowed for additional lowering of the vehicle during a stop. The floor height in the first and second doors was then reduced to 250 mm. A folding ramp was installed in the central entrance, which, when tilted by the driver, allowed for wheelchair access.

Jelcz M121 console

Comparing to Jelcz 120M, significant changes were introduced in the MN120M body. The vehicle received front and rear walls typical for the 120M model, but made of plastic. The front and rear bumpers were also made of plastic and on the front there were large, rectangular headlights with integrated turn signals. The side windows were attached to the body by gluing, which was an innovative technique in Jelcz (previously it was used only in the M180 model and the prototype 120M). The sides of the bus were made of galvanised steel plate, while trunk lids are made of aluminium plate. Due to the differences in the level of the floor inside the vehicle, the line of the side windows did not run smoothly. In the front part, above the side window, there was a built-in space for the line number and direction display.

Jelcz M121MB #110 on route

The interior of Jelcz MN120M was equipped with 34 single semi-soft seats. The concept of using soft seats covered with artificial material, which was well known to passengers of PR110M, M11 and 120M buses, was abandoned here. Opposite the middle door there was a space for a wheelchair with the possibility of securing it with belts. The new bus also had a completely new semi-open driver’s cab made of plastic. Few changes have appeared on the desktop itself. The walls and ceiling of the interior were finished with laminated boards, while the floor was lined with non-slip lining. Heating was provided by an independent unit, a front heater and convector heaters arranged in a linear manner. The ventilation of the interior was provided by the sliding upper parts of side windows and the roof covers. The additional equipment options of the Jelcz MN120M turned out to be extremely innovative on the Polish market: on-board computer with the possibility of announcing the route and stop names, electronic displays, tinted side windows.

Serial production of low-entry Jelcz buses started in the first quarter of 1995, under the trade name M121M. Apart from the version with the MAN engine, the M121MB version was offered with a 12-liter Mercedes engine and an 11-liter engine from Mielec (M121). In order to reduce costs, the option of mounting scrolling directional boards and semi-hard Astromal seats has been introduced. The prototype copy was purchased by MPK Wrocław (Wrocław’s Municipal Transport Company), where it was used till 2008. In 1995 Jelcz M121M buses appeared also on the streets of Krakow, Warsaw and Poznań, and gradually gained popularity in many other Polish cities. In Wrocław, there were 27 buses of this series (not counting the prototype) with the rolling stock numbers 9502–9528. In 1996, this bus model underwent a thorough modernisation, which can be recognised from the outside by a new front wall and a changed window line on the left side. However, the modernisation was not limited to the visual aspect, but made the bus construction more like foreign designs. In the front part, some of the platforms under the seats was removed and the fuel tank was moved to the vicinity of the first side window. This resulted in five seats accessible directly from the low floor. Not much (Volvo 7000 had 14 such seats), but at that time it was a success (Mercedes O405N/2 had a similar number of seats accessible from the low floor). There were 35 buses of this modernised type operating in Wrocław (rolling stock numbers 9529–9563).

In 2000, the Jelcz M121 underwent another modernisation – the production of the body from stainless steel began. In 2004, the Jelcz M121I with a new front and Iveco engine was presented – a trade fair copy of this type travelled across Poland to finally reach MPK Świdnica. In 2005, more changes were introduced, including aligning the top and bottom line of windows, using the VDO desktop and changing the door type.

The Jelcz M121I and Jelcz M121MB buses were an ideal solution for companies looking for a piece of low floor at the lowest possible price. From today’s perspective, the design of this bus has many disadvantages and is very outdated. However, it should be remembered that at the end of the 20 th century it was the only Polish low-floor bus, one of the few offered on our market at that time, and it was certainly the cheapest vehicle compared to its foreign competitors. The production of this type of buses ended with the bankruptcy of the Jelcz factory in 2008. The text by Andrzej Pionka comes from the “Kasownik” journal from 2006 (with minor changes to update the content).

History of Jelcz M121MB #110

Jelcz M121MB #110 on route

The bus we present was produced in 1996 as the 14 th copy of this series. It is equipped with a Mercedes engine with a capacity of 12 litres. This bus did not find its way to regular public transport – it was purchased for a hospital in Pomerania. There more stood than he rode, and therefore its interior retained a breath of factory freshness. The bus came to Wrocław in 2009 and had its body repaired at the Kumex company. Later it appeared on the lines replacing trams during track repairs, being rented by MPK Wrocław. It is currently operational and it is possible to rent it for occasional journeys.

Parameters

Parameters
Built	1996
Total number of passengers	100
Number of seats	34
Length	12000 mm
Heigth	3020 mm
Width	2500 mm
Netto weight	10240 kg
Total weight	17500 kg
Engine power	Mercedes OM447hLA 11967 dm3 (184kW)