Railwayana
Signal Box items
Rule Books which contain detailed Rules and Regulations applicable to signalling practice and the safe operation of the railway can be found by following the relevant option on the 'GWR internal publications' page under the 'MEMORABILIA/Book collection' menu tab. This page is dedicated to some of the many other items which could be found in an operational Signal Box.
It might be of interest to first outline the history and early operation of signal boxes. Safe operation of the railway was originally overseen by the Railway Police whose responsibilities included ensuring there was a suitable time delay between trains and thus, hopefully, avoid a collision. There was however no reliable way in which they could be warned if a train had broken down, was simply running slowly, or of any other threat to safety, and this inevitably lead to some bad accidents.
Signal boxes started to appear in the early 1870s when a new method of controlling the flow of rail traffic was developed called the Fixed (or Absolute) Block, with signalmen assuming responsibility for all operational aspects of the railway. This method of working was based on dividing the railway line into sections, or blocks, with only one train being allowed to occupy a block at any one time. Such sections of line are separated by, and protected by, signals. Whilst there were detail differences between the railway companies, the basic principle remained the same. In the simplest case with three signal boxes on a stretch of line without junctions (such as Radley – Culham – Appleford Crossing), the central of the three boxes would receive a request for a train to be accepted, they would set any relevant points (turnouts or switches) and signals. They would then signal their acceptance and request acceptance by the next signal box along the line. When the train had passed, the signals behind it would be set back to danger and the signaller would inform the next signal box when the train has left the section. This communication was by single-stroke bell signals supported by indications on devices known as Block Instruments.
Courtesy of Pendon Museum
The signal box at Culham was opened in November 1874 with the first signalman being Charles Tarrant (great grandfather of the broadcaster Chris Tarrant). He first joined the G.W.R. in February 1873 as a policeman at Steventon transferring to Culham in the July, thence to Bletchington before returning to Culham as a signalman. Until 1954 there was also a small box sited on the Radley side of the Nuneham river crossing which served to split the block between Radley and Culham. This box only operated between 6 a.m. and 10 p.m. Monday to Saturday and was closed on Sundays, unlike the others mentioned which at that time were continually manned.
This detail from an undated photograph in the Pendon Museum archives shows the instrument shelf in the original signal box at Culham. On it can be seen, from left to right, a block bell and block instrument, the box closing switch, another block instrument and mushroom block bell with an unidentified instrument at the end. On the front are what appears to be a bell push, an early brass bodied plunger (mounted directly above the corresponding lever, it releases an electric lock thus allowing the lever to be operated), and a signal lever collar on its hook. Each of the block instruments is identified by a plate on the shelf edge below it. Just visible above the instruments is the lower right hand corner of the signalling diagram for CulhamClick or tap to see a photograph of the 1952 diagram from Culham. This showed the track layout and location of all the signals and points controlled by the box, and each was numbered to correspond with their controlling lever.
Early GWR 'Sheep dome' block bell
An early example with a dark case and dovetailed joints back and front. The GWR used five standard shaped bells, Mushroom, Sheep, Cow, Flat top and Church, each giving a different ring. Where several of these bells were installed, such as at Culham, each would be of a different shape so as to easily distinguish which bell was being operated. Different standard codes were tapped out to pass messages between signal boxes. In practice the remote bell only would ring but we have wired ours up to soundClick or tap to see our information sheet in pdf format when the tapper is pressed so as to demonstrate its operation.
Later GWR 'Flat top' block bell
This is a fine example of a GWR pattern block bell with a light wood case which was manufactured exclusively by R.E.Thompson & Co. Ltd. of Walton on Thames in Surrey. This instrument is fitted with the less common 'Flat' dome bell mounted on a Crucifix pedestal and our example still retains the original makers plate on the front of the base.
Early GWR block instrument
A fine example of the iconic Great Western Railway double line block indicator, marked H.White & Co. London N. This instrument is one of the earlier pattern with the ogee moulding on the case and the individual reminder flaps. The rear of the instrument has been upgraded by the GWR at Reading to deal with later signalling safety improvements.
Later GWR block instrument
Another instrument manufactured by R.E.Thompson & Co. Ltd. who were the largest outside instrument manufacture and suppliers to the Great Western Railway and later to BR Western Region. This first class example of a later G.W.R. 1947 pattern instrument produced in a light wood case. Such examples are hard to find and were made to match other light cased block instruments and bells. These instruments were made from Bakelite during WWII due to a shortage of hardwoords but went back to wood after the war.
GWR signal lamp repeater
Our example is a later pattern Great Western Railway wood cased lamp repeater manufactured by R.E.Thompson & Co, in a mahogany case. This instrument is with its original brass signal numper plate '1'. These lamp repeaters were mounted on the block shelf in the signalbox and indicated to the signalman whether the oil lamp on the correspondingly numbered signal at the lineside was lit. In the top of the signal lamp case was a bi-metal unit whose contacts were closed when heat from the flame caused the unit to expand. In this state the indicator flag would show LAMP IN, if the lamp were to go out the expander unit would cool down and the contacts would open breaking the circuit causing a bell to ring and the flag show LAMP OUT.
GWR signal box release plunger
Signal box release plungers are simply a "push to make" switch that allows the signalman to operate a signal or point lever by unlocking its electric lock. Generally mounted on the block shelf above the corresponding lever, they would have a number plate to identify the lever but this is missing from our example. Originally made from brass, later versions such as ours had a bakelite cover and base. Bakelite is a type of plastic that was invented in 1907 by Leo Baekeland and became widely used in the 1920s and 1930s for various applications and was a good electrical insulator. We believe that the GWR started using Bakelite release plungers in the 1930s, and that they continued in use until the 1960s.
GWR box closing switch
These switches were provided to allow a signal box to close (switch out), possibly at night or on Sundays by allowing all instruments and bells in the boxes on either side to be electrically connected thus forming one longer single blockClick or tap to see our information sheet in pdf format between them. Before closing a box, all signals would have been set to 'Off', and all points set to allow the safe passage of trains. This switch in our collection is a 14 way example and although there are no maker's markings or plate it is believed to be a late model suplied by R.E.Thompson.
Train Register
One very important item in signal boxes was the Train Register. In this book were meticulously recorded the details of every train movement controlled by the box. Such registers can still be found in use in any manual signal box such as those operating on many of the present day heritage and preserved lines. We sadly missed the opportunity to buy one from the signal box at Culham some years ago but did find a couple others to add to our collection as representative examples. The British Railways one is an unused example, whereas the two Network Rail ones from Ledbury Signal Box have been used and cover the period 14th March to 18th July 2005.
Click or tap on either thumbnail to see some pages from the registers.
