Boat of Garten South Signal Box is located only a few yards South of Boat of Garten station, and is on the East side of the line.  This 'box is the largest signal box on the railway, and houses a 30 lever McKenzie & Holland frame with Cam and Tappet locking.

This signal box is largely of a brick construction, with some wooden sections around the front and sides of the operating room.  Access to the locking room is at ground level.  The operating room has a traditional coal fire - a feature appreciated by the signalmen on cold operating days.  The box has recently been extensively repainted, outside and in, and is looking very good indeed.

This 'box controls all running line points, facing point locks and signals at the South end of Boat of Garten.  All points within the two station yard areas are locally operated.

Of the 30 levers in the frame, 21 are operational, one of which is used for Locking Only, four are not installed and the other five are spares.  There are three facing point lock levers, four point levers, four main signal levers, seven shunt signal levers (one of which controls a yellow disc), one King lever and one lever which releases electrical locks at Boat of Garten North - effectively acting as a release lever.

When the railway is working a two-train day, Boat of Garten South becomes the hub of all signalling operations, with the signalman at Boat of Garten North operating under his control.  The Signalman on duty in the South 'box is responsible for all decisions regarding the movement of trains into the station area, and is also responsible for communicating with station staff, and the Responsible Officer, in the event of any unforseen changes to the planned running.