The battery subsystem is a system. It needs both charging, but also the discharging circuit to work to use the battery or super cap.
Bottom line- yours is not passing "the test".
"When I cycle the power to try and move it to forward or reverse the sounds and lights turn off."
The many things it could be:
Updates- system identified as likely being PS2 3V https://mthtrains.com/10-3024-1
The wiring harness and connector failed from leaking original battery. I've seen where the corrosion just entirely destroys the wire from the inside where it wicks up the strands. This tends to happen less on PS2 3V but any wiring harness failure could prevent connection between the battery and the board.
The charging circuit is not working- check voltage on the battery connector while applying power to engine- it should be a rising voltage - especially true on a super capacitor (BCR) if not charging- can never provide power later. Again, I measure the baseline voltage without track power applied, and then ideally measured at the board battery circuit terminals- measure in place while track power is applied and watch the voltage rise. If there is no rise or the measured voltage is low (less than 2.4V nominal on PS3)- it's probably not charging.
The discharge circuit is damaged. This may not show physical signs of damage. It just means, you know you have voltage and charging at the battery connector as the source- now the test is- if the board stack can use that energy (voltage) of the battery to power sounds. This is the one test that really matters. If we know we start with a charged battery or capacitor, and that voltage is at the board terminals through the wiring harness, and the harness is low resistance (so a good known harness), and yet when we power down the track and the board cannot continue playing sounds-this points at a board failure.
PS2 3V boards were more repairable because the upper board of the 2 board stack- the "power board" can be repaired in some cases or replaced.
This previous topic talks about some of those details of components on the board https://ogrforum.com/topic/154307983685100861
