Dudding Hill Line
The Dudding Hill Line (or Dudding Hill Loop) is a railway line in northwest London running from Acton to Cricklewood. It branches from the North London Line between Acton Central and Willesden Junction stations and heads north then east, terminating at a triangular junction with the Midland Main Line between Cricklewood and Hendon. There are intermediate junctions with the West Coast Main Line at Harlesden and the Chiltern Main Line at Neasden.
The line has no passenger service, no stations, no electrification and is lightly used by freight. It is roughly 4 miles long.
The line was opened in 1875 by the Midland Railway to connect its Cricklewood goods yard to other lines.  It had stations at Dudding Hill and Harlesden (also called Harrow Road and Stonebridge Park).  From 1878 to 1880  it formed the basis of the Super Outer Circle, which ran from St Pancras to Earl's Court via Cricklewood, Acton and the District Line.  It was closed to passenger traffic completely in 1902.
The line is also known as the Midland & South Western Joint.
- Dudding Hill station Subterranea Britannica