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 Culham
Click or tap link for a larger image. 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.
GWR block bells
The GWR used five standard shaped bells, Mushroom, Sheep, Cow, Flat top and Church, each giving a different ring. Where more than one block bell was installed 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 boxes.
An early example 'Sheep Dome' bell 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.
This is a fine example of a later GWR 'Flat top' 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.
GWR block instruments
In 1855, at the age of 23, Charles Spagnoletti joined the GWR as their first Telegraph Superintendent. He developed a complete system of block signalling and associated instruments which was first used on the Metropolitan and District railway, but was soon adopted by the GWR. Different block instruments were produced for either single or double line working, and we have a few examples of the latter in our collection as seen below. This type of instrument survived in use beyond the end of the GWR in 1948, and into the 21st century. It is believed that the final operational Network Rail examples were located in Banbury North and South signal boxes which were both decommissioned in the summer of 2016. We were fortunate to visit Banbury North in September 2016
Banbury North signal box in September 2016 shortly before its demolition.
This is an example of a very early pattern double Spagnoletti block instrument. It is a handsome instrument which retains its original brass fittings and unmodified contact box on the back and is marked with the maker's name of H.White & Co. London N.. Examples of this early and unmodified type are now quite rare.
Another fine example of the early pattern Great Western Railway double line block indicator, this one marked H.White & Co. London N. The rear of the instrument has been upgraded by the GWR Signals Department at Reading to deal with later signalling safety improvements.
This last instrument was manufactured by R.E.Thompson & Co. Ltd. who were the largest outside instrument manufacturer and supplier to the Great Western Railway and later to BR Western Region. This first class example of a later G.W.R. 1947 pattern instrument is housed 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 hardwoods but went back to wood after the war.
GWR signal lamp repeaters and warning bell
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 instrument would show LAMP IN. If the lamp were to go out the expander unit would cool down opening the contacts thus breaking the circuit and causing a warning bell to ring and the instrument to show LAMP OUT. The warning bell could be manually silenced by means of a knob on the front of the instrument, and could be tested using the key or push-button to the left.
Our first example is a 'slot' type of Great Western Railway lamp repeater manufactured by R.E.Thompson & Co, and housed in a mahogany case. This instrument is with its original brass signal number plate '1'.
This second example is a later pattern Great Western Railway wood cased lamp repeater, again manufactured by R.E.Thompson & Co., and dates from the late 1940s. The instrument is smaller than the earlier one shown above and has a different mechanism, although the principle remained the same. The circuits supporting this version utilised post office relays which allowed for cheaper production costs. This instrument carries a later style white 'Traffolite' plate with the signal number '2'. These instruments were made from Bakelite during WWII due to a shortage of hardwoods but went back to wood after the war.
Typical of many GWR signal box lamp warning bells, it is believed that our example originated from one of the two closed signal boxes at Somerton in Somerset as it has 'Somerton' written in pencil on the back.
GWR box closing switches
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 10 way switch is an example of an early design. Although there are no maker's markings or plate it is believed to been manufactured by R.E.Thompson.
This is an example of a later design switch. It is a 14 way example and although there are no maker's markings or plate it is believed to been supplied by R.E.Thompson.
GWR Release plungers
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 normally have a plate identifying its associated lever.
Early versions such as this one were made from brass. Our example has no makers name but has the number 7035 stamped on the underside of its base and would appear not to have carried a number plate as no screw hole are present on the cover.
One of these style brass plungers can be seen on the shelf edge in the photograph taken inside the signal box at Culham above.
This later version of a release plunger has 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. The number plate which would have identified its associated lever is missing from our example but the screw holes where it would have been attached are visible.
GWR lever reminder collar
These cast iron lever reminders would be placed over a signal or point lever by the signalman to prevent operation of the lever in circumstances such as a train waiting at a signal. This example is of the earlier pattern which measures around 4½" in diameter and was used on 5¼" center lever frames, this allowed for these devices to be placed on neighbouring levers without them touching each other. A smaller version was used with later 4" centre lever frames. Some terrible accidents have occurred due to signalman failing to use these small devices.
One of these collars can be seen on a hook on the shelf edge in the photograph taken inside the signal box at Culham above.
Train Registers
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.
