Edwin Knowles Mann is listed as a "inspector" for the railroad on the 1920 census in Salt Lake City.  By the time he died he was a mechanic for the Bamberger Electric Railroad in Bountiful Utah.  It appears that he was an inspector for a different railroad as the photograph of him near the railroad at the time is clearly not the Bamberger.

The Bamberger Electric Railroad started as a steam powered railway in 1891.  The railroad never expanded beyond the single original line from Salt Lake City to Ogden Utah.  The railroad switched to electric power in 1910.  Passenger service survived until 1952.  The line was used for freight service until 1959 when it was abandoned altogether.