MLR nos. 1-4 were four steam locomotives that operated on the Matheran Hill Railway, supplied by German engineering company Orenstein and Koppel.[5] These locomotives served the railway from its inauguration in 1907, until 1982, when they were withdrawn from service, and completely replaced by diesel locomotives.[6]
To navigate the tight curves on the MLR, the locomotives were fitted with an articulated wheel design, based on a patent by one John Clark in 1870.[7] The design allowed for the rods to remain parallel to the engine at all times, while the wheels would follow the track's curves.[8] The driving axles were Klien-Lindners.
The locomotives served on the line exclusively until 1965, when diesel traction was introduced on the line. Eventually, the four engines were retired in 1982,[9] with all of them preserved at various locations.