Kato automatic level crossing 20-650

[andydoob]

purchased one of these from greedybay, I plugged everything in (I have the double track extension as well), the unit powered up straight away and was blinking and ringing just fine but I cannot get the sensors to work at all, they dont' seem to have any effect on the crossing. I have no idea how they work but only read they are electrical sensors.

any help would be really good. thanks in advance