Kato Crossing gate problems in N scale

[ginzokid]

Having a problem with the Kato N scale crossing gate and Intermountain cars only. The gates work just fine until an IM car crosses it, then the gates want to raise again, until another manufacturer's car like Atlas crosses and then they go down again. You can imagine the poor gates having a nervous breakdown as each IM car arrives...bobbing up and down.

This only happens with the IM cars. Anyone know if there is something in the IM cars like weights or wheel sensors that cause this abnormal behavior?
8D