This reversing spur was an isolated part of the Lothian Lines (North British Railway) built to allow northbound departures from the Lady Victoria Colliery.
South of the stone built Brewer's Bush Bridge a trailing crossover connected the northbound to the southbound line. South of this the reversing spur line came off the southbound line and ran south to a pair of reversing spurs which ran south on the east side of the main line. At the north end, these were connected by a loop on the east side of the main line which passed under a girder bridge directly east of the Brewer's Bush Bridge and then connected into the private railway beside Lady Victoria Pit Signal Box.