Five bucks for a GG1, very nice indeed! Powerful beasts the GG1s, but with an odd sort of beauty to them. I presume she'll be being dragged by a diesel perhaps off to a maintenance shop somewhere? Don't recall seeing any overhead cables in the other shots.
Love the caboose too, fantastic bit of weathering there, LED lights are an excellent addition to any stock, and indeed to buildings too, can be very atmosphere to turn the lights off and watch the railroad run in the night.
Have you thought of replacing the plastic coal in the coal hopper with a layer of crushed real coal?
Something a bit like this (although this is a tender, not a hopper):
Also, I remember one...magazine I think it was, showing a way that if you get an empty hopper or wagon, measure it up and create a load that slots into the wagon but is easily removed, then you can simulate empty and full loads on the layout.
Some links that might be of interest, UK based but I'm sure that they will still be relevant to a US layout:
http://georgedentmodelmaker.blogspot...ill-em-up.html
https://www.model-railways-live.co.u..._Tips_number_3