The museum opened in 1975 when the Isle of Man Road Services, a subsidiary of the railway company, relocated to their new garage, which still exists today at the foot of the main platform.
At that time, the railway operated only between Port Erin and Castletown, in an experimental season with the goal of reducing running costs.
The main exhibition hall is housed in a converted bus garage that once belonged to Isle of Man Road Services, itself a division of the old railway company which was nationalised in 1976.
The following represents and main exhibits of locomotives and rolling stock contained in the museum since its opening in 1975; during events periods and photographic charters certain items of stock are removed and alternatives take their places where available; since 2014 F.75 and G.19 have been plinthed on an isolated section of track, joined on another plinth in 2020 by No.1 Sutherland.
In addition to the framed exhibits of old posters and the like, further displays are mounted on the walls of the station building itself in the waiting room and booking office.