Need help with Lionel Type S Transformer

On Lionel transformers the connection to the binding post inside the case has been troublesome.  The other thing I would focus on is the whistle control assembly.  Without pushing the whistle button, the power should go straight through that contact and out the other side to the U post.  Then there is the contact plate where the reserve button switch is located. Without pushing the reverse button, power should go straight through here fron the variable contact to the whistle control board.  With the cover off, just follow the path of the power through the transformer. Since you have power on the fixed terminals, the variable windings have to be good.  So you need to follow the electrical path from the variable voltage contact to the U post.

Thanks David...you were correct.

Followed the electrical path and the reverse button was the issue.

I had cleaned the contacts using Crocus cloth....a small thread of the cloth got left behind between the contacts which kept the circuit open.

At first I thought....can't be that simple    ..............but lo and behold that was it.

Working fine now.  Also took the time to re-solder and firm up the post contacts as you mentioned.

Thanks...Dave