OLD PLYMOUTH . UK
Plus parts of the South Hams and West Devon
www.oldplymouth.uk
 

  Brian Moseley, Plymouth
Webpage created: April 21, 2018
Webpage updated: March 30, 2019

        

RAILWAYS IN OLD PLYMOUTH  |  MAIN LINE, BRENT STATION TO PLYMOUTH STATION (MILLBAY)

PLYMPTON SIGNAL BOX

Plympton Signal Box on the Down platform.
A 45xx class tank engine runs through  the Station towards Laira.
C M and J M Bentley.

At 241 miles 60 chains, or at mile post 241, a 60 miles per hour speed limited was imposed through Plympton Station until mile post 242.

Plympton Signal Box was on the Down platform of Plympton Station, at 241 miles 75 chains.  It was 22 feet 5 inches long, by 11 feet 6 inches wide.

The late Larry Crosier (1929-2010), a founder of the Signalling Record Society, upon whose research this information is based, has stated that Down Distant Signal was authorised on October 10th 1878 and that there is photographic evidence that a lever for operating the crossover at the western end of Plympton Station was wire locked, indicating that a Signal Box was probably in existence.

Certainly a Signal Box was in existence by 1886, when the Working Time Table for that year indicated that it was switched out on Sundays and the section became Hemerdon to Tavistock Junction.  Apparently the signals and points were not interlocked at that time.

Following the conversion from broad gauge to standard gauge in 1891, a new signal box was in use by February 1895.  This Box received a new 35-lever frame in 1918 to enable Down railmotor trains to start from the Up platform, where they had terminated from Saltash.

In 1941 the Great Western Railway Company installed Down and Up Goods Running Loops between Plympton and Tavistock Junction Marshalling Yard and the frame had to be re-locked.  At first the Up Goods Running Loop Home Signal returned to Danger immediately the train engine broke the track circuit beyond the signal and this meant that the driver of the banking engine had to effectively pass the signal at Danger.  This situation was subsequently altered and the frame was again relocked in 1958.

During the British Railways era, the Box was open continuously, as were Hemerdon Siding Box and Tavistock Junction Box on either side of it.  The Refuge Siding on the Up side could accommodate 217 wagons plus engine and guard's van.

The Signalling Regulations required that the "Is Line Clear?" for Down trains was sent to Tavistock Junction Signal Box as normal, when the "Train Entering Section" code was received from Hemerdon Siding Signal Box.  For Up trains the "Is Line Clear?" had to be sent to Hemerdon Siding Signal Box as soon as it was received from Tavistock Junction.  The Up Main Home signal could not be lowered until the main line was clear as far as the Up Starting signal.  In the case of freight trains assisted by a banking engine at the rear, the Up Main Home or Up Loop to Main Home signals could not be lowered until the "Line Clear" code had been received from Hemerdon Siding Signal Box.  The Plympton Signalman had to advise Plymouth Control of the passing times of all Up freight trains and he also had to advise both Tavistock Junction and Lipson Junction signalmen when he had accepted a Down express train, which usually meant that it had just passed Ivybridge Signal Box.  This was to give them the chance to keep the main line clear of slower traffic in to North Road Plymouth Station.  Larry Crosier relates in his book "Mechanical Signalling in Plymouth" that the unofficial method was to send the bell code for "Training Approaching", 2-1, which was clearly not authorised to be used at Plympton Signal Box in the normal way.  This method ceased when the Plympton Down Distant signal was converted to a colour light one, after which the "Is Line Clear?" for a Down train was  passed right on to Tavistock Junction.

Because of the speed  attained during the descent of Hemerdon Bank the Down Home and Down Main to Siding signals had repeaters signals just ahead of the Down platform.

There were in the 1950s two Ground Frames on either side of the tracks.

It might be pointed out that the main line between Plympton Station and Tavistock Junction Signal Box was liable to flooding.

Plympton Station closed as from March 3rd 1959 but Plympton Signal Box remained in operation until June 25th 1967.

 

  With grateful acknowledgement to the late Mr Laurence 'Larry' William Crosier (1929-2010) of the Great Western Railway Company (1943-1947);
British Railways (1948-c1994); the Plymouth Railway Circle, the Lee Moor Tramway Preservation Society, and the Signalling Record Society.