Problem solved!!!!  Thanks to you folks.  It turns that the front coupler on the engine had a lot of up and down play and the curved wire that hangs down (fake air line?) was catching on the crossing's wheel guides and pulling the engine off track.  I tightened the coupler screw a little and, behold, problem solved instantly.  And many thanks for the layout Joe.

JCS44 

For Joe Satnik ( or is it "Doc") - Thanks for the layout idea!  That one is a little better than mine and still has room for a couple of future sidings, etc.

John

Wow!  I want to really thank everyone for all the input/suggestions.  My plan was to use the 30 deg crossing to create the longest run I could on a 4 x 6 layout for my grandson (and me), so there's a lot of curves.  I'm trying to create a large outside loop and use the crossing for an inside loop as large as possible, so it's not a true figure 8.  From what you've all replied, I think I probably do have a geometry problem with the alignment of the curves to the crossing, so I'll play with that.  It also sounds like I need at least a short straight on all sides of the crossing and I gotta get down there with my magnifiers to see whats going on (old eyes).

Many thanks,
John

I only have the one engine, GP35, I think.  Seems to always hang up in same spot.  Perhaps there's a plastic burr on the crossing, because sometimes it just stops cold.  Also, since I have curves joining the crossing, maybe the engine trucks aren't totally straight when they reach the crossing (?).

Thanks for the input!

Hello everyone - newbie here.

I'm putting together a very basic layout for my grandson ( and myself.  I recently bought a 30 degree crossing for the layout and having problems with derailing almost everytime the engine starts across it.  Sometimes it just stops cold.  Anyone else have problems with these things?  I do have curve sections feeding the crossing.

Thanks, John