Reply to "Constant Voltage board"

I have an 0-8-0 steam switcher with the 5 volt board in the tender that has no CV board in the engine. The only difference, I notice in operation, is the smoke unit heating elements turn off and the fire glow goes out, when the engine is thrown into reverse. It still puffs smoke but only for a few feet til the elements cool down. It does have a tender reverse light that comes on when the fire glow goes out. At first I thought it was all a malfunction but have come to believe it was a sacrifice MTH had to make because of the lack of room in the engine for the CV board.