Application of thyristors in railway technology - Measures for the prevention of functional disturbance in signalling installations

Summary

The electrical circuit of a traction current comprises, besides the traction vehicle, the substation, the overhead line, rails, track, ground and often an earth cable and a return conductor.

Signalling installations usually use the track as a transmission medium. It can therefore be exposed to interference, which may result in unsafe operation.

The signalling track circuits may use D.C. (not with D.C. traction) or A.C.

There are A.C. track circuits which operate with 25 - 400 Hz, sine-wave or modulated signal. Also pulsed track circuits, A.C. track circuits at 0,8 - 3 kHz (sine-wave, pulse- or frequency modulated A.C.) or A.C. track circuits at 8 -100 kHz are used.

Axle counters are also used.

Driving cab signalling via track circuits with discontinuous or continuous function exist. Also intermittent train control with resonant systems or carrier frequencies (4,5 - 27 MHz) are used.

In the second half of the leaflet, possible measures to improve the electromagnetic compatibility between the disturbance source and the disturbed object are listed. Measures can be made in the substation, in the track and in the traction vehicle. Also the design of the track circuits are dealt with.