This is the junction for Lanark used by trains from Glasgow to join the single track branch from the double track West Coast Main Line. Unfortunately the east to south curve closed and the former service from Edinburgh would now be very awkward to operate.
The present layout is a return to its original form. The branch, opened in 1854, was single and approached only from the west.
It was to become a double track junction, one junction of a triangle of junctions for Lanark. In 1864 an east to south cure opened from Silvermuir East Junction to Silvermuir South Junction respectively. The signal box was located on the south side of the junction.
The box closed in 1934 when all three boxes were replaced with a single box, 'Lanark Junction', set back in the 'V' of the junction at Silvermuir East Junction.
The branch was singled again in 1971. The box closed in 1973, replaced by the Motherwell Signalling Centre.