London To Aylesbury Line - Route Description

Route Description

From Marylebone the line runs through a series of tunnels as far as Finchley Road, from where the line runs overground and runs parallel to the Metropolitan and Jubilee Lines. A passenger on a train departing from Marylebone can see the Metropolitan Line just before the train enters the first tunnel, because the tunnels used by these two lines run only a few yards apart. At Neasden Junction, the Chiltern Main Line diverges to the west, while the Aylesbury line continues north parallel to the underground lines, passing Wembley Stadium.

The line then joins the Metropolitan Line tracks a few yards south of Harrow-on-the-Hill station and shares this track with the London Underground's fast Metropolitan Line services to Amersham from London Baker Street. This section runs parallel to the slow Met Line to Northwood and Watford. The line goes under the M25 north of Rickmansworth. At Chalfont & Latimer station, the Chesham branch diverges and Amersham is the final Metropolitan Line stop.

After Amersham, the line returns to Network Rail control and runs north to Aylesbury, running parallel to the A413 road for the majority of this section. At Aylesbury, the Princes Risborough line joins and this is where major maintenance work on trains is carried out. Beyond Aylesbury, the line is single track. North of Aylesbury Vale Parkway it is freight only, and runs through Quainton Road railway station to Calvert, where there is a waste depot. Beyond Calvert, there is a junction; one line goes east and joins the Varsity Line, while the main line goes north and becomes the dismantled Great Central Main Line.

Because of its route through the Chiltern Hills and perhaps due to lack of overall planning, having been built in stages, the line has some steep gradients and harsh curves. This is one of the main reasons why the GCR built a new line (the Chiltern Main Line) to Woodford Halse in 1906.