In order to improve the traffic flow approaching the single-line Royal Albert Bridge, a Down Avoiding Line was brought into operation where slow freight trains or Saltash Suburban Rail Motors could be shunted to allow faster passenger trains to overtake.  This required a signal box between Saint Budeaux Platform and the Royal Albert Bridge Signal Box and Saint Budeaux Signal Box was opened at 250½ miles from London on Sunday June 28th 1908.

On and as from Friday June 2nd 1916 the Box was renamed Saint Budeaux West Signal Box when a new one was opened near Weston Mill Viaduct to control access to the new branch line to the Bull Point Ordnance Depot.

On the night of April 28th/29th 1941 Saint Budeaux West Signal Box was destroyed by a direct hit of a high-explosive bomb.  The Box was rebuilt and reopened on November 5th that same year.

Although both the old and new Boxes contained 21 levers there was a small difference in the two Box's dimensions: the old one was 25 feet by 12 feet by 8 feet while the new one was 22 feet 9 inches by 12 feet 1 inch by 8 feet.

The rules allowed the signalman at Saint Budeaux West Signal Box the authority to transfer a slow Up freight train to the Down main line while a faster Up train overtook it.  In 1936 the Box was manned from 4.30am until 9.30pm.

Saint Budeaux West Signal Box was closed on and as from June 22nd 1952 when the operation of its signals and points were transferred to Royal Albert Bridge Signal Box.