A friend from the Texas Western Club brought this for me to look at. It is an old lithograph used for autorack PR. The file is very large when viewed full size. The original was badly decomposed and stained in spots, but I worked it in Photoshop to improve the image. I used Canon's photostich to merge three separate scans together.
The small picture gives you an idea what it is. The zip file is the 17mb image.