Wiring MTH crossing gates to Lionel 153IR

I don't have either device but one troubleshooting approach would be to test each device separately.

For example you can test the gate by itself:

gate red ac power, gate black to ac ground

then touch the gate NC to ac ground to simulate the inactive condition (gate up)

then touch the gate NO to ac ground to simulate the active condition (gate down)

If this doesn't work then pairing it with the 153IR won't either.

I'm fairly sure the 153IR has an electromechanical relay inside.  So when it turns on/off you should hear a faint relay click.  So with just ac power and ac ground hooked up to the 153IR it should "click" when you wave your hand and then un-click after the knob-settable seconds of time-delay.  Again, I don't have one and am speculating that you can hear this click in a quiet room.  Or if you have a meter you can electrical test the continuity of the NO and NC contacts.  Again this is simply trying to isolate the problem.

I suppose another possibility is the transformer you're using has issues so that too could be something to look at or measure if you have a meter.

Thank you Stan2004:

I do hear the click on the 153IR when I activate it and again when the delay is complete.

I'll try the testing you suggested and also try a different transformer and let you know.

Thank you

You can easily hear the click of the relay on all of the 153IR pieces I have, that's about a dozen.  It's just a SPDT set of contacts, so there's no magic to it.