The possible serie number of the loco is unknown to me - if it has one. It's made in Tampere at Tampella Locomotive Works in 1917 and served 1918-1968 at Hyvinkää - Karkkila line (44 km) before it was moved to Forssa - Humppila line the part of which between Forssa - Jokioinen does no more exist. In addition to Museum RW's few diesel locos there are five steam locos about which this is number 5. Its nickname is "Sohvi".