I remember this series very well from the 1950's, and "Railroad Detective" was actually the ORIGINAL title of the series,at least the early episodes.When the title was changed I don't know, but Railroad Detective was certainly the first I knew it under. I remember that opening, with the old steam train racing along at top speed with its whistle screaming.
shareYou may be thinking of another of Dale's series, The Iron Horse
shareYou're thinking of the old Jim Davis series "Stories of the Century", which was also known as "Matt Clark Railroad Detective".
I would imagine it easy to confuse the two because they were so similar. Both Matt Clark and Jim Hardie managed (individually) to collar every big name bad guy in the Wild West in the official course of their duties.