Compressed Air Trams By John Prentice

5. BERN, SWITZERLAND

Following its success in Nantes and Paris, the Mékarski company turned its eyes to Switzerland. On 1st July 1889, in a consortium with others (including Vevey and Ludwig & Schopfer), Mékarski was granted a concession to build and operate a line in Bern, and the Berner Tramway Gesellschaft was formed.

A metre gauge line, with trackwork by Demerbe & Cie. of Belgium, was constructed, running the 3.1 km. from Baerengraben via Bahnhof to Bremgarten Friedhof (the bear pit to the cemetery). Cars were reversed at termini by turntable, an extra one being later added at Bahnhof, the central point. After testing a public service commenced on 1st October 1890, with a ten minute headway. In the first full year of service, 1,146,532 passengers were carried.

Bern Mékarski car 5 on the turntable at Baerengraben depot in the autumn of 1896. Note the panels open to reveal the mechanism.

The depot was at Baerengraben where there were three compressors, flywheel driven at 80-90 r.p.m., one normally kept in reserve. Compressed air and steam (for re-heating water in the bouillotte) were supplied via two mains from the depot to a charge point at the terminus by Nydeggbrucke). In the early days there were problems with condensate freezing in these pipes in winter, later solved by lagging and re-routing.

There were ten cars (numbered 1-10) which were very similar to the later cars at Nantes. They were built to Mékarski designs by Ludwig & Schopfer of Bern (now Von Roll AG), with bodywork by Blech & Winkeleisen. The trucks were two axle of 1.6 metre wheelbase, the front axle being driven by two cylinders of 130mm bore and 220mm stroke, the axles being joined by connecting rods. Walschaert's valve gear was used and all mechanism was enclosed by horizontal hinged panels. The bodies were single ended with a large rear platform and were 6.9 metres long and seated 28, weighing 9.5 ton laden. The cars had 700 mm diameter wheels, and travelled at about 12 kph with a maximum speed of 15 kph. These Bern Mékarski cars developed 10 horse power.

The Bern Mékarski Car.
From an original drawing of Bern cars 1 - 10
This design is similar to the later Nantes Cars
and to the cars of the smaller French systems.

Eighty kilograms of air was stored in ten reservoir cylinders mounted transversely under the floor with a capacity of 2,100 litres, split 1,375 litres in a main set with 745 litres in reserve. These reservoir cylinders were charged at 30 atmospheres. Air passed to a standard Mékarski patent bouillotte mounted on the front platform. This was 350 mm diameter and 1.475 metres high. It was three quarters full of water at 165 degrees centigrade and on top was mounted the usual speed control wheel, which supplied air to the driving cylinders at 5-9 atmospheres. Four-block wheel brakes were applied by air from the traction supply being fed via a three-way valve, similar to the Paris cars described later.

Rear view of a Bern Mékarski car in Spitalgasse, probably around 1900. Electric trams on other routes can still be seen at this location.

The cars ran successfully for eleven years, although other new routes all used steam traction and the air system was not extended. Electric traction won out and the route was electrified, the last air car running on 15th November 1901, trams themselves being replaced on this service by the trolleybuses that run today, partly in 1940 (Baerengraben) and partly in 1965 (Friedhof).

Note: It has been suggested that two similar looking compressed air cars ran in Neuchâtel, but these were in fact gas engined. (see Lytham Gas Tram postcard for details).

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