serve trains running via Tikkurila to Tampere, St Petersburg and other points north and east, platforms 11 and 12 serve express trains via the Espoo line to Turku. Platforms 12–19, which do not stretch to the building itself, are on the west side and serve local trains on the Leppävaara and Kehärata routes. The tracks funnel into separate express and local tracks for both the Espoo and the Tikkurila routes with the express tracks in the middle and the local tracks on the outside, aligning with their respective platforms. This gives eight principal tracks but there is an additional ninth express track for the Tikkurila route out through the Pasila station, the first stop out, about five minutes or 3 km north of Central. Helsinki Central serves as a hub for Finnish transport. There are many platforms for local buses on both the west and the east sides of the main station building. The Helsinki Metro Central Railway Station metro station is located under the main station building, linked through Asematunneli, which has entrances in the main hall of the station and at various points in the surrounding streets. The majority of Helsinki's tram routes pass in front of or to the west of the station. The Helsinki central bus station is located at Kamppi Center, about 400 m, or one metro stop, to the west of the railway station. There are two squares near the railway station: the Railway Square and the Eliel Square. Although the Helsinki Airport is reachable from the station by the I/P commuter rail service, there are also regular bus connections between the station and the airport: two regional buses operated by HSL, and a private express coach operated for Finnair. Tracks The first railway connection from Helsinki to Hämeenlinna only had a single track. However, the cliff cut at Linnunlaulu was fitted for two parallel tracks right from the start. As traffic increased, a second track was built next to the first one in 1892. The Linnunlaulu cliff has since been further cut and the track lining has been widened several times. The Helsinki railway station was originally built outside the city centre. This left enough space to build a railway machinery yard and a locomotive hangar next to the station. However, they later became encompassed by the growing city and so the locomotive hangar was gradually moved to the Pasila machinery yard since