Thanks for the help! I would think the Bachman speaker would be compatible, but I will order one and find out.

I want to replace the factory decoder in my GP7 with a Tsunami2. It looks like there is a round area inside the fuel tank on the bottom of the loco. Is that meant for a speaker? if so, what kind of speaker will fit?

I am having a problem with my #6 crossover switches. Some of the switch points appear to be so loose when switched that a car going over the point causes it to moved away from the rail, which then causes a derailment of the following car. When this first happened, I assumed that I caused the problem and bought a new switch, but the new one is having the same issue on both switches of the crossover. So is this switch defective or is there something I am missing and need to do? Anyone having the same issue? Thanks for any help.