Turnout problem

[Law Dawg 86]

I have 2 E-Z track turnouts that are giving me a problem.One is a left turnout and the other a right. When the locomotives are operating to go straight as opposed to entering the turnout, they derail on the front trucks. This happens every time. I have Atlas & Athearn diesels. When the engines go the other way they go through the switch fine. Any suggestions? I have spent hours and can't seem to find the cause.At first I thought the air hoses were interfering,but this does not appear to be the case.Thanks. 

[Len]

Is the straight point rail tight against the stock rail when the switch is set for straight through operation, or is there a gap between the point rail and stock rail??

If there's even a small gap the front truck wheels may be 'picking' the point rail, allowing the wheel flange to go between the point rail and stock rail, resulting in a derailment.

Sometimes this can be fixed by using a pair of needle nose pliers to gentley adjust the point rail until it makes firm contact with the stock rail when the switch is thrown.

Len