The Pruett softcover used a narrow gauge cover photo, but the later University of Colorado Press version went back to a standard gauge photo. It's also interesting that it's been reprinted twice considering that it was never a good seller. I think it's a great read, and despite the relatively small number of photos compared to typical railroad books (even in the original), I thought it would become collectible. You can easily find original edition hardcover copies in good condition for under $30 including shipping on eBay and book search sites like abebooks.com, and it isn't unusual to find one for under $20. Used softcover copies are cheaper yet. The hardcover edition does have a lot more photos than softcover ones, and even though the Fogg painting used on the cover is standard gauge, it makes for a better looking book, so I'd suggest always looking for hardcover version.
I stopped by Mike Trent's house in Boulder in probably 1984, and by chance Margaret Coel was there going over old photos to use in the book to decide which to use and what to put in the captions. I don't think I contributed much, but it did get me mentioned in the acknowledgements. About 10 years later, I got laid off from my first professional job, and my co-workers gave be a parting gift. It was a Pruett softcover edition of Goin' Railroading. They thought that I'd like it because it had trains. I checked to see if my name was still in the acknowledgements, but it wasn't (probably since they took out most of the photos). I still hung on to it for a while, but eventually donated it to an auction for the DSP&P Historical Society. I still have my original hardcover with Margaret's note and signature.