9V Battery Back Up Dangers?

All of my Legacy locomotives have been purchased new, and so I haven't duplicated your situation exactly. But I have removed and replaced a 9v battery on more than one occasion. They are intended to be replaced, and so I cannot imagine that there should be any reason to not install one in a used locomotive. I would however suggest that it may be prudent to only replace a battery when the locomotive is not on a powered track. Doing this should remove any potential risk, however small. 

Hi Thomas, I've never experienced any problems with swapping out batteries, and as Nicole said, they were meant to be replaced as needed.  A number of my TMCC engines are hitting the 10 year mark, so I have replaced batteries numerous times until I stopped the madness a few years ago.  After I started to aquire a sizeable amount of TMCC, I worried about damage from leaking batteries, so I removed every 9 volt battery applicable.  I've noticed no sound outages.  Only if I cut the track power off does the sound end abruptly.  If I use the shut down button on the cab 2, the shut down sequence still works.  Try running without batteries, you might be better off (safer).

Stack

I've got to save that RickO.

I've taken batteries out and put batteries in dozens of TMCC and Legacy engines, both new and used.  It's never been a problem, and none of them have ever died in the process.

I have to believe this was a coincidence and not a result of simply changing the battery.

I only have 6 engines with TMCC and put the Dallee Brc in all and never had a problem. J&W also makes a charging system for there BCR to use in TMCC engines. 

Thanks for the advice everyone.

I ask this because, at the moment, I am a conventional operator - and even in my club's command enviroment, we have the occassional dead spots and it's something I dislike having my Legacy engines experiencing.