Maintenance for MTH Proto 2 Engines

Yes I agree (mostly) with the battery replacement, plus I would replace them a BCR2 and never worry about a dead or bad battery ever again.

I have many engines that have batteries that are 8 or more years old. They still work but when they go, I replace them with a BCR type. The only exception to the is the Older PS2 5v boards that have the 9 volt style battery. I replace those with new NiMH battery. 

Now if you don't want to go through the hassle of changing all of the batteries,  You can put your engines on the track, power up to about 15 volts and let them charge for a while (about 15 minutes & turn of the smoke unit during this). shut off the power and see if the shutdown sounds continue to play for about 10 more seconds. If this is successful, your battery is good. Note that if this test fails with a PS1 engine, you should not make any attempt to operate the engine until a new battery has been placed in the engine.

I would also do regular Lube maintenance as these have been stored for a while plus prime the smoke unit with fresh fluid.

I brought all of my 19+ year old PS2 5V locomotives out of retirement 4 years ago. The first thing I did was replace the batteries. Some, I had to replace traction tires.

Thank you very much.