on former maps. Express train to Saunakallio The former G train ran from Helsinki to Saunakallio. The line had six services a day in both directions and it was the only train with letter designation on the Helsinki–Riihimäki route that did not stop at Tikkurila. The service was started on 4 June 2007. It was abolished in 2011 in order to improve management of traffic and timetable keeping on the Main Line especially during winter conditions. The letter G was reintroduced in 2017 on the previously unlettered line between Riihimäki and Lahti. Limited-stop train to Riihimäki The H train ran from Helsinki to Riihimäki and operated with an interval of one hour. After stopping in Pasila, Tikkurila and Kerava, the line proceeded to stop at all stations. The letter H is an original designation from 1972. Several stops (listed above in parentheses) were procedurally closed in 1990–98 due to low passenger numbers and the H trains disturbing other traffic by being too slow. In March 2016, the Purola and Nuppulinna stations were closed and the H trains were replaced with the R train that now has two additional stops and double the frequency. Stopping train to Vantaankoski The former M train ran from Helsinki to Vantaankoski. The train operated with 10–30 minutes intervals, stopping at all stations. The service ran continuously between 1975, when the track to Martinlaakso was completed, and 2015, when the Vantaankoski Line was continued by the Ring Rail Line. In 1991, the line was continued one stop further to Vantaankoski. The letter M stood for Martinlaakso, though the M train was substituted in 2015 with the P train, to avoid confusion with the Helsinki Metro. The letter M is now (since 2019) used for Tampere commuter rail service entirely operating in the Tampere region in Pirkanmaa. Stopping train to Kerava The N train ran from Helsinki to Kerava, stopping at all stations. On its final years in operation, the train operated only on early morning and on evening during weekdays, with 30 minute intervals. On weekends the train operated more frequently with 10 minute intervals on Saturday and 15 minute intervals on Sunday. The N train was abolished in August 2019 and was replaced by K train, which started to stop at all stations. Stopping train to Hiekkaharju The former P train ran from Helsinki to Hiekkaharju, stopping at all stations. The service was started in