The station is a major junction with numerous crossovers north and south of station enabling flexibility when routing trains. South of the station there are four LU tracks paired by direction as "Fast" and "Local" lines to/from Baker Street and two "Main line" tracks to/from Marylebone. North of the station, the Uxbridge branch diverges from the other routes by means of a borrowing junction. Above this, Harrow North Junction separates the "Local line" towards North Harrow and the "Main line" towards Moor Park.
London Underground
London Underground services at Harrow-on-the-Hill are provided by the Metropolitan line. The adjacent Underground stations are Northwick Park, Moor Park, North Harrow and West Harrow The Metropolitan line is unique in operating an express service. "Fast" and "Semi-fast" services do not stop between Harrow-on-the-Hill and Finchley Road. The "Fast" lines at stations between Moor Park, Harrow and Wembley Park have no platforms. Southbound services go to either Baker Street or continue beyond to the line's terminus at Aldgate. Off-peak trains from Amersham, Chesham and Uxbridge generally terminate at Aldgate, with a 4tph service from Watford to Baker Street, however during peak hours trains from all branches go to/from all destinations.
History
The station was opened as "Harrow" on 2 August 1880, when the Metropolitan Railway was extended from its previous terminus at Willesden Green. Its name was changed to "Harrow-on-the-Hill" on 1 June 1894. Like some other Underground stations, the name is an example of marketing rather than precision; in this case the town "proper" of the same name is at the top of Harrow Hill, while the station is located at the foot of the hill to the north, which was at the time of opening was a small hamlet called Greenhill and has since become the main town proper of Harrow. Had the governors of Harrow School not made objections during the planning stage, it is possible that the Metropolitan Railway might have followed a different route taking it closer to the town centre on the hill. The station is at the heart of Metro-land.
The station building is above ground with the six platforms in a cutting. Two are predominantly used by NR services and the other four by the Metropolitan line; the NR platforms are electrified with the LU system and incoming LU trains on some routes can be diverted into them should this be necessary during closures of tracks in the area. The station has two entrances, one on Station Approach and one on College Road. During opening hoursthe Station is popular as a shortcut, removing the longer walk via the bridge at Station Road, as it is possible to walk through the ticket office area without passing through the ticket gates. The present main station building replaced older structures at the London end of the platforms ; it consists of a main circulating area built across all tracks with stairs down to all platforms and both street entrances thus requiring a number of steps to be negotiated by all users. A pedestrian tunnel connected all the platforms to the adjacent and now closed Post Officesorting office, whose site is now subject to a major redevelopment. A new office block called Avanta House was built in the 1980s or early 1990s on top of the station's College Road entrance.
Step-free access
Harrow-on-the-Hill is due to gain step free access via College Road as part of the tranche of stations due for completion in 2020.
