You need to make sure that the track near the activator is free to move a bit. If it's firmly screwed down, it'll never flex enough to trigger the switch. This is why I favor the IR sensors beside the track, that is not an issue with those. This also goes right under the track, not under the roadbed.

 

It's between the road bed and the track and does not really seem that tightly screwed down.

We got 2 IR sensors for other things but I hated to have to keep getting those for everything I want to be activated like this. I'll play with it some more....before I hit ebay looking for IRs

 

The track has to be loose enough for the sensor springs to raise it sufficiently to open the contacts. If that's not true, the actuator will not function properly. There really isn't much else that can go wrong.

 

The picture showed it with the "ties" sitting on the activator. I watched it at track level, trying many adjustments of the knob and still no luck. I moved it so the rails sit on it. I watched it at track level and train wasn't pushing it down enough to activate. Played with the knob some more and it is now working!!

 

Glad you got it working. Those are a bit "twitchy" at times.