The rear coupler always opens up when the engine goes over the Fastrack Operating Section, Other engines don't have this problem and the same GG1 works fine when going over the operating track section with Lionel Tubular Track. Does anyone else have problems with GG1 engines and the Fastrack operating track section?
The GG1 from 1947 (No. 2332) would have a shoe to activate its electric uncoupler when the button was pressed on the RCS. The FasTrack Operating Track Section is supposed to replace the RCS and should uncouple that original GG1 when its button is pressed.
So check to see if your GG1 has an uncoupling shoe on its truck and then check the FasTrack Operating Track Section to see if it is wired incorrectly to have power on rails 4 and 5 even when the button is not pressed.
It is very unlikely that this will solve your problem since your engine is from the MPC period. But without pictures, I can only make wild guesses.
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