Safety circuit for railway level crossing - has triggering switches in front of and on barriers with logic network controlling barriers for fail=safe operation

摘要

The safety system is for a level crossing with a switch upstream of the gates in each direction. The switch controls the safety equipment at the level crossing. There is also a switching system at the level crossing operated by the train when passing the cross-over point. The system contains flip-flops (7) which allow the switching systems upstream of the crossing to operate the safety systems at the crossing. The safety systems at the crossing can be blocked in the on position by another set of flip-flops (8). The logic circuit involves a number of AND-gates and threshold value switches.