For batteries you may want to check out the MTO battery website out of Red Lion PA.
Click on the "Trains" button in the category line up. All kinds of shapes, sizes and power.
The battery packs have a built in circuit breaker and a special battery charger. Very safe.
I have been adding a bunch of industrial switching yards which normally would have many blocks, power feed drops, switchable S.P.D.T. frog leads, etc, etc. No more. I had an GP-9, an RS-11 and a GP-35 set up with battery power. They are designated yard engines. Normally I just operate one engine at a time so a dozen on board battery powered R/C locomotives would be more than sufficient.
Probably just sell some of the track powered locos, I find that I do not need them.
Had not gotten to powering up two of my commuter branch line tracks so there are now battery powered gas electrics, RDCs and a K-4 designated to run those routes. Also, I have several large mainline battery powered engines which do some of the heavy lifting.
A side benefit is now seeing just how few engines really I "need" to run a large RR. Me thinks that we folks go way overboard in our purchases.