I hope this is the correct place to ask this. I have been purchasing trains as I can and now I am wanting to start to repair the locomotives that I have and do some maintenance on them. As I have been looking though some of the things on line, it references them by GP numbers and such. I was wondering if I was to take off the cab if I will find these type of numbers or any kind of numbers somewhere inside of the engine. Also was wondering if there is somewhere to purchase a repair manual to have on hand for when I do start repairing my engines.