EMD GP7 Demonstrators?

Hello, I was wandering about the EMD gp7 domonstators 100,200 and 300, what railroads tried them out and which roads 100,200, and 300 sold to after they were deomonstrated? Also Where they all the Silver, Yellow and blue paint scheme like #100. I'm going to purchase the kalmbach book "GM Geeps" later but was wandering about them before hand. Also are there any photos on the the deomstrators on the internet? Thanks for any information, it's greatly appreciated.
N&WJ

All three were sold to the Chicago & North Western once they were finished with the demonstration tour where they were numbered 1518-1520. Not exactly sure what railroads they toured on, but judging from the plethora of GP7s that were ordered, it was probably fairly extensive. The C&NW scrapped the 2nd and 3rd demonstrators when they were retired in the 80's, but restored the high nose on the first one (1518), gave it a new paint job, and donated it to IRM, where it is today.

Thanks for thre reply, very helpful.