Trams of the Konstal N and Konstal 4N types

Konstal N trams were the first type of tram-cars constructed in Poland after the Second World War. They were possibly the fastest – and therefore burdened with various short-comings – answer of the devastated industry for the lack of rolling- stock in most of Polish cities. Although those trams had a very simple and rather obsolete construction, for several reasons they had to serve for many years and became an inseparable part of the cultural landscape not only in Wroclaw. Even though Konstal N trams were constructed in Poland, their project was created in pre-war Germany. They were a simplified version of a German war-time tram (so called Kriegsstrassenbahnwagen, KSW), which already was of a very simple construction that stemmed from the economic situation of the Second World War. The fact that Polish engineers mostly copied an already existing project, instead of preparing a new one, resulted from the severe devastation of the Polish industry after the period 1939–1945. First Konstal N cars were manufactured in 1948, however, due to the lack of traction engines, they were all trailer cars (the ND type). Production of motor coaches started a year later and was conducted simultaneously by the Steel Constructions Work „Konstal” in Chorzów (Chorzowska Wytwórnia Konstrukcji Stalowych „Konstal”) and the North Shipyard, although the first company prepared the engineering drawings and was responsible for the whole process. Most wagons were manufactured in Chorzów. The letter “N” in the name of the tram originates from the word “Normalised”, which corresponds with the fact that the construction and particular parts of the vehicle followed the Polish technical norms, introduced just in that time. Later the letter “N” preceded by different numbers became a standard symbol of all tram-cars originating from the “Konstal” factory (for example the 4N or 102N types). Globally, 516 trams of the Konstal N type were constructed between 1949 and 1956, when – following only a slightly improved project – the production of Konstal 4N type wagons started. A representative of this series is the historical tram no. 1444 operating in Wroclaw.

Trams of the N and 4N generation were originally two-way and two-sided vehicles. Motorman posts were located at both ends of the wagon, there were two entrances at both sides of the tram. Cars of this type were delivered to several Polish cities, in majority of which – just like in Wroclaw – not every end of a line had a form of a loop way. Quite often it just ended with a stub track, where the direction had to be changed and a motorman started using the second driving post. The total length of this two-axle tram was 10,4 meter (approximately 34 feet), while the weight was 13,500 kilograms (almost 30 000 pounds). Every motor coach was equipped with two 60 kW engines, which enabled to develop the speed of 55 km per hour (approximately 34 miles per hour). All vehicles had originally two types of breaks: electrical and manual (block breaks). The whole electric equipment was supplied with high voltage (in Wroclaw 600V), that includes the heating and lights, which were connected in series. The wiper was operated manually. Every tram could serve 83 passengers, however only 12 persons in the N type car (or 16 in the 4N type car) had a sitting place. A motorman did not have a separated cabin, his working place was just isolated from the passenger unit with a thick curtain.

Konstal N and 4N trams were equipped with sanders, which enabled to regain tractive adhesion in a situation when wheels skidded. Sanders are really helpful in autumn, when fallen leafs mashed by tram’s wheels create a greasy, slippery substance. Originally every vehicle had four sand reservoirs located under the first and the last pair of seats. In a situation when wheels skidded, a motorman pulled a special handle and the sand was poured from two of the reservoirs on the head of the rail right in front of the wheels. The sand increases friction and in this way enables to regain adhesion. Sanders were installed in all pre-war trams, they were also used in first Polish post-war cars, but at the turn of the 1960’s and the 1970’s engineers substituted them with other, more modern devices. However, from the perspective of time, simple sanders occurred to be the best mechanism protecting trams from skidding and nowadays they are once again quite often used.

First Konstal N trams were delivered to Wroclaw in 1956. In total the Municipal Communication Company (Miejskie Przedsiębiorstwo Komunikacyjne) in Wroclaw received 49 new motor coaches and 109 new trailer cars. The deliveries of the 4N and 4ND (trailer cars) type trams lasted in the period 1957–1962. Later – between 1964 and 1969 – Wroclaw obtained Konstal N trams phased out from Warsaw – 57 motor and 105 trailer coaches. For this reason it was possible to progressively immobilise the pre-war rolling-stock, which up to that time was regularly operating in passenger service. Products from the Konstal company started to dominate on Wroclaw’s rails. However, because the capital city of Lower Silesia received more trailer cars than motor coaches, for many years one could see a post- war wagon pulled by a pre-war one.

Konstal N and 4N trams were started being modernised as early as in the middle of the 1960’s. The biggest change was the reconstruction of the originally two-way car into a one-way one, which corresponded with the gradual process of replacing stub tracks with loop ways. One of the motorman posts and two entrances and sanders on the adequate side were removed. In the place of the removed motorman post a converter was installed, i.e. a devise changing high voltage (600V) into low voltage (40V). Thanks to the on-load voltage, every tram could have been equipped with an electromagnetic slipper brakes (that is the third type of brakes), head-lights irrespective from the changes of the contact line voltage, clearance lights and electric bells. The doors were also considerably modified. Originally they were single, massive doors shifted manually in the direction of the motorman posts. Due to heavy weight they were quite dangerous. With time they were substituted with double doors, which from 1967 were provided with electrical engines enabling opening and closing from the motorman post. It is quite interesting that the whole mechanism consisted of an ordinary drill engine, a rod and a bicycle chain.

Wagons of the N and 4N generation were gradually immobilised in the 1980’s, when the deliveries of modern Konstal 105Na trams started. Last cars of those types operated in passenger service in 1991. At present in the capital city of Lower Silesia only a few modified Konstal N and 4N trams survived. They are used as technical cars or not used at all; usually they decay without proper care. Fortunately, one wagon (inventory no. 1444) was restored in 2012 by the Club of Municipal Transport Lovers (Klub Sympatyków Transportu Miejskiego), an association gathering people interested in preservation of historical trams and buses, and it is now protected by law as a part of the national technical heritage. This particular tram was constructed in 1960 and was operating regularly until 1991, when it became a technical car of the Municipal Communication Company in Wroclaw. After the restoration, the tram no. 1444 is a representative of Konstal N and 4N coaches from the end of their regular exploitation. Apart from Wroclaw, trams of the presented types were preserved in Katowice, Krakow, Warsaw, Poznan and Szczecin.

Text: Krzysztof Kołodziejczyk