This was the junction for the mineral line to Earnock Quarry, Stewartfield Quarry and Hartfield Quarry. From the junction the siding ran north east, passed through a loop, swung over the main line and ran west to a reversing spur with a loop near Udston. From there it continued to the quarries.
As shown in the 1897 OS map there was a signal box at the junction, on the north/east side of the line. There were catch points downhill on the southbound line.
By the 1912 map the box was on the south/west side. The catch points were gone but a trailing crossover had been installed at the junction. The box closed in 1917. The main line closed in 1953.
The site is now overgrown and is now a footpath.
The location was between High Blantyre (to the north) and Meikle Earnock stations. (Townhill Signal Box was a little to the north.)