Ampthill Tunnel

Ampthill tunnel is a railway tunnel at Ampthill on the Midland Main Line, being positioned between Bedford and Flitwick. It consists of two separate bores, each one accommodating double-track throughout.

The first Ampthill Tunnel was built during the 1860s; growing demand on the line led to the original double-track configuration being inadequate for further growth. Thus, during the 1890s, a second Ampthill Tunnel was constructed directly alongside, facilitating the Midland Railway's expansion plans of running a quadruple-track arrangement between Kettering and London wherever practical to do so. Both bores have remained active through to the present day. During mid 2012, Ampthill Tunnel was subject to a series of high speed evaluation runs, including a record maximum speed for the route of 125 miles per hour (201 km/h); in the following year, the line speeds were increased to 125 mph along much of the Midland Main Line.