I’m also working on a 1:1 scale Subway train in my train room. It’s actually all original parts. Anyway, I’m working on all the lighting now. I’ll be using 12 VDC. I was able to swap out all the glass bulbs for LED’s except for two LED’s on a PCB board inside a passenger door indication panel. I believe this board was fed with 32 VDC. I’m assuming there’s something that dropped the current down for the LEDs. Please have a look and see if there’s components I need to swap out of simply don’t need for just lightining the original LEDs again.