SWITZERLAND’s Zentralbahn (ZB), which operates a 98km metre-gauge network, is currently carrying out tests to determine whether adhesion operation could be used at gradients of up to 12.5%. As pneumatic braking will not cope with such gradients in adverse weather conditions, a combination of pneumatic and magnetic wheel brakes is being tested.

ZB operates the Brünig line linking Lucerne to Interlaken which has a maximum gradient 12.1% and the line from Lucerne to Engelberg with a maximum gradient 24.6%, both of which are fitted with sections of Riggenbach rack equipment.

To carry out the tests, ZB is using a single electric railcar dating from 1985, which has been equipped with an electric brake as well as with measuring devices by the Institute for Rail Vehicles and Transport Systems (IFS), which is part of the Rhine Westphalia Technical High School in Aachen, Germany (RWTH). 

Initial simulations suggest that braking distances without rack operation would be safe enough for normal operation. Braking tests have now been carried out on a section with a 10.5% gradient on the Engelberg line and on the Berner Oberland Railway.

The railcar cannot operate directly on the 15kV 16.7Hz ZB network as it is equipped for 1.2kV dc operation. Instead, for the tests, the unit was coupled to a ZB diesel shunter which supplies air and electricity for its brakes.

The research partners are now reviewing the results, including the cost of energy used by electric braking before further tests are carried out. Positive results would allow significant reductions in the cost of train acquisition and train and track maintenance, not only on the ZB Brünig line, but also on several other lines in Switzerland and other countries equipped with rack on mountain lines.