Lower Hutt) and Johnsonville. Most stations are served by only one line. Most trains are the FP class Matangi electric multiple units, in sets of two to eight cars, introduced from 2011. They displaced the older DM class English Electric units, the last of which were withdrawn from service in 2012, and the EM class Ganz Mavag units, the last of which were withdrawn from service in 2016. The Wairarapa line beyond Upper Hutt is not electrified, so the Wairarapa Connection trains to Masterton are diesel-hauled with SW and SE class carriages. There are long-distance trains to Palmerston North (the Capital Connection commuter train) and Auckland (the Northern Explorer). These are not part of the Wellington transport system. History Electric suburban services began in July 1938, following the opening of the Tawa flat deviation of the North Island Main Trunk (NIMT). The Johnsonville Line, the former route of the NIMT out of the capital, was the first line to be electrified. By 1940 the NIMT (the present Kapiti Line) had been electrified as far north as Paekakariki. The Hutt Valley Line was electrified to Taitā in 1953 to coincide with major state housing developments in the area. In 1954, the Wairarapa railway line was diverted between Petone and Haywards via Waterloo and Taitā, with the old line truncated to Melling to form the Melling Line. Electrification was extended to Upper Hutt in 1955. Also in 1955, the 9 km Rimutaka Tunnel between Upper Hutt and Featherston opened, bypassing the laborious Rimutaka Incline and reducing the travel time from Wellington to Featherston to just over one hour, and from Wellington to Masterton to one-and-three-quarter hours. The Wairarapa Connection service started nine years later, after morning and afternoon peak services started to exceed the 176-seat capacity of the diesel railcars (twin NZR RM class) then used. Electrification was extended to Paraparaumu in 1982, and to Waikanae in February 2011 to coincide with the arrival of the new Matangi electric multiple units. Services The Metlink network consists of five lines totalling . All lines originate from Wellington railway station, at the northern end of the Wellington central business district. Around of the network is electrified at 1600 V direct current with overhead lines. The only part not electrified is the Wairarapa Line beyond Upper Hutt; as a result Wairarapa Connection trains are diesel-hauled. Until 2001, Tranz Metro also operated the Capital Connection service