For me, it would be worth more if it had PS3 inside.
The PS1 electronics are probably still good inside but the MTH battery is shot. Don't run it with that battery! Replace it and give it a try. You may like conventional for a change. I have to run in command for the majority of time. For fun, I'll set up a simple loop around the Christmas tree with conventional control. Since it's a special train for you, you may leave it alone until the time comes necessary for changing.