Derailing on an HO Crossover

[gehdoc97]

I have a DCC Sante Fe Engine with sound (HO) and when I run it over my Bachman Crossover the rear truck slides off the main line and heads down the tracks to the inner line and causes the layout to short.

What could be the causes of this happening?  I have checked the track gauge, the "air" hose position and length, the condition of the track, the switch itself, and the condition of the truck.  I am a befuddled newbie just returning to model railroading.

[jward]

have you checqued the wheel guage on that rear truck?

you may also want to file a nie taper on the switchpoint where the tender derails. block the point open with a watchstick, then using a jewelers file, file a nice bevel on the edge of the point where the wheel flange should ride.