Railroad Magazine began as a true "pulp" magazine, printed on low-grade, high-wood pulp paper. The paper was meant to be cheap; it was never intended to last long.
From the late 1930s onward, the magazine was printed in such high volumes that it is fairly easy to find issues in relatively good condition. Brittle pages, however, are to be expected and I suspect that unless magazines are de-acidified, fully intact issues will become progressively harder to find over time.
The magazine started out as a vehicle for fiction and followed in the footsteps of "story" magazines such as Saturday Night, Ballou's, Kelly's Pictorial and a host of others. As early as the 1850's railroad adventures were very popular and often appeared in serial form in story newspapers, spread out over several issues.
Frank Munsey started Railroad Man's Magazine in 1906 as a male companion to his successful Argosy Magazine. It proved moderately successful and lasted in independent form under Munsey until early 1919. At that time, he combined it with Argosy Magazine under the banner of Argosy and Railroad Man's Magazine. I suspect that the combined magazine cut into total revenues because Munsey separated the two magazines less than two years later.
The magazine kept the Railroad Man's title until early 1932 when it morphed into Railroad Stories with vivid covers more in keeping with popular pulp mystery and "true crime" magazines.
Railroad Stories lasted a little over five years and gradually started offering more factual material. The masthead changed to Railroad Magazine in 1937. From the number of surviving magazines, it appears circulation jumped rather dramatically. Fictional pieces survived for a few years, but ultimately gave way to photos and statistics of real railroading.
Five years after the name change, the magazine shifted ownership to Popular Publications and the magazine gradually took on a slicker appearance. Paper quality generally improved, although covers were always attached somewhat flimsily.
Issue numbering: Railroad Magazine was sloppy in its volume/issue numbering. It is not unusual to find skipped numbers and numbers out of sequence. Sometimes the magazine got back on track after numbering mistakes and sometimes it did not. Volume and issue numbers are generally confirmed only for those issues that I have owned.