| 摘要 |
In order to switch on safety devices (S) at a railway crossing (B) as a function of the direction of travel by means of vehicles (F) travelling over a track (G), in each case two rail switches (K11, K12; K21, K22) which cooperate in pairs are provided on each side of the railway crossing (B). A direction detection circuit (R11, R21) is connected downstream of each pair of rail switches. The pairs of rail switches act in each case on both direction detection circuits (R11, R12). Only if both circuits supply the same output signals can it be concluded that the entire system is operating free of faults. <IMAGE>
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