Lynton and Barnstaple model signalling
by Bob Barnard

ed note: Bob is a professional signalling engineer and his work in this field is seminal. It also shows what happens when you bring your work home!

The definitive description of the signalling arrangements on the original L&B line is given at:

http://www.trainweb.org/railwest/lbrsignals.html

There are still many unknowns about details of the original signalling, and the operation of the line, but this website includes what is probably the best information available to date, and is updated if new information comes to light.
 

Although my L&B model is an attempt to recreate the original line in 009 scale, in order to be able to operate it in a manner equivalent to the original line, there are some areas where alternative signalling standards have been devised, in order to overcome the practical constraints of a small-scale model. Obvious differences from the original signalling include:

• There is no need for telephones to allow operators at different stations to converse, as the layout is housed in one room

• It is not practical to carry physical tablets on 009 trains (4mm scale working tablet instruments would be a step too far!)

• Lever frames need to be large enough to suit 12”/1 foot scale fingers

• It may be necessary to operate stations from either side, especially at exhibitions

• Facing point locks are not really required on a model, especially as those on the L&B were “economical”, i.e. they did not involve the use of separate levers

• L&B level crossings were released from the nearest signal box, and operated locally by hand. This may not be ideal in a model situation.

I wanted some system to replace the tablet instruments for single line sections. On some secondary routes around the world, so-called “Tokenless Block” systems are used to release the signals controlling entry to single line sections, and this seemed like an ideal solution for my model. Therefore, I developed a Tokenless Block System (TBS) based on BR practice. In order for this to operate, it needs to be interlocked with the starting signals at passing loops, which the Tyers instruments on the original line were not. However, this seemed to be a sensible compromise. Surprisingly, in view of its suitability, I am not aware of tokenless block having been used by other modellers.

Many model layouts these days use oversize but realistic-looking lever frames to control points and signals. This provides a satisfyingly authentic method of operation. A few of these models also have working mechanical interlocking between the levers. With very simple track layouts, I decided that my long-term aim should be to provide full mechanical interlocking.

It is possible to build-in the lever frames into the station layouts, and operate points and signals mechanically by rodding under the baseboards. However, this effectively prevents operation of the station from the rear side. The alternative is to build a separate “signal box” unit, and operate points and signals electrically. I have used both approaches in my L&B models.
A set of common engineering standards has evolved as I have built my models, so that spares can be used at any station. These standards include power supply arrangements, block circuits and electrical drive arrangements for points, signals and level crossings.

A number of interim signalling arrangements have been implemented on the model, in the interests of saving time, but it is intended that these will eventually be brought up to the general standard.

The following sections include more detailed descriptions of the common subsystems.
 

A standardised form of Tokenless Block control is used for each single line section, using one circuit in each direction in a lineside cable route, and providing facilities for acceptance of trains and release of signals. The tokenless block system also provides block bell communication between stations.

The Tokenless Block System is a method of controlling single line sections without the use of physical tokens. It is derived from British Railways Tokenless Block systems, and is intended for implementation on model railways.

In order to clear the starting signal for a train to proceed into the single line section, it is necessary for the signalmen at the two ends of the section to establish, by the correct sequence of operations, that the line is clear. The signalmen can then set the block section for the appropriate direction, and the appropriate starting and home signals can be cleared according to normal block working methods. When the train arrives complete at the other end of the section, that signalman normalises the block once again, ready for another train.

At each end of the section, there is a block instrument and a relay set. The relay set contains 4 relays and is fed from a local 15 Volt a.c. power supply, and requires contact inputs indicating the status of the home and starter signals at the station. It provides 12 Volt d.c. outputs to the home and starter signal lever locks.

Tokenless Block instrument (l) and Relay Set (r)

The circuit between the relay units at the two ends of the block section consists of two conductors and a common return path.

The system is designed for use with semaphore signals with electric lever locks. Additional circuits can be added to interface to colour light signals.

The normal sequence of operation for the section between A and B is as follows:

• After the passage of a train and the normalisation of the block, each signalman sets his block instrument to “Accept”, provided no shunting is taking place into the block section. The block status is indicated to both signalmen as “Normal” (Yellow)

• When the next train arrives (say) at A, the A signalman sets his block instrument to “Normal”. He then presses “Offer”

• At B, automatic acceptance of the train occurs, and the block status is indicated as “Blocked” (Red). If the B instrument were not set to “Accept”, this would not occur, and an audible warning would be given

• When acceptance has occurred, the block status at A is indicated as “Accepted” (Green)

• The A signalman may now, at any time, release his starting signal towards B, using the economiser button to energise the signal lever lock as he pulls the lever. As the signal clears, the block status changes to “Blocked” (Red). If he replaces the starting signal to danger, he cannot then clear it again. This prevents a second train being accidentally signalled into the section.

• The B signalman can now, at any time, clear his home signal from the direction of A, using the economiser button as he pulls the lever. If he changes his mind about the route for the train, he can replace his home signal to danger, move the points, and then clear it (or any other appropriate home signal) again

• The A signalman replaces his starting signal to danger once the train has departed from A

• The B signalman replaces his home signal to danger once the train has arrived at B

• The B signalman checks that the train has arrived complete at B (tail lamp) and then sets his block instrument to “Normal”, and presses “Train Arrived”. The block section status is then restored to “Normal” and indicated to both signalmen by “Normal” (yellow) indications

• Each signalman then sets his block instrument to “Accept” again, provided no shunting is taking place into the block section. The block status is indicated to both signalmen as “Normal” (Yellow).

The Block Instruments are located on (non-prototypical) block shelves over the lever frame at each station. Two different designs of relay set are used, but all units have standard connectors for the block circuit, allowing any two stations to be linked. The two instruments at a passing loop can also be linked to one another for testing. The appearance of the block instruments is very 1960s, with grey boxes and labels against each indication or switch.

This tokenless block system works extremely well, and again gives an authentic feel to operation of the model, even though it is quite different to the original Tyers tablet system used on the L&B.
 

Lever frames, with mechanical interlocking between levers, are (or will be) provided at all stations and passing loops.

Home and starting signal levers are released, when permitted by the Tokenless Block system, via 12 Volt d.c. solenoid lever locks fitted with economiser buttons. Signal clearance is dependent on local detection of electrically operated points and level crossings, and of slots from adjacent signal boxes.

Two alternative approaches to point and signal control are adopted:

• The lever frame, interlocking and block shelf may be located at the station itself. In this case, station area points and signals are operated directly from the lever frame via rodding, and detection is provided purely according to lever position.

• The lever frame, interlocking and block shelf may be remotely located (or portable, for ease of maintenance), and connected to the station by multicore cabling (D-type computer cables, 9 way and 25 way). This approach means that a non-interlocked switch panel may be used as an interim solution, in place of a fully interlocked lever frame.

In the case of electrical operation, the lever frame (or switch panel) provides feeds as follows:

• 12 Volt d.c. feed, switched in polarity by the lever, is used to feed each electric motor (slow-acting) point machine. Electrical point detection is provided, with a correspondence circuit used to release a lever lock to allow the controlling lever to reach the fully normal or reverse position.

• 12 Volt d.c. feed, switched in polarity by the lever, is used to feed each semaphore signal via local point detection contact(s). Signals may therefore, in principle, be operated by several different types of mechanism:

              o 12 Volt d.c. relay mechanisms, via a diode

              o 12 Volt d.c. motor mechanisms (e.g. slow-acting point machines)

              o Memory wire mechanisms, via a diode (tried but not used)

              o Direct operation of bi-colour LED colour light signals (not used)

In all cases, electrical "Signal On" detection is provided at the signal, either by detection switches or by contacts of the operating relay mechanism

• 12 Volt d.c. feed, switched in polarity by the lever, is used to release each level crossing.
 

Unlocked mechanical ground frames are provided at in-section sidings.

It would be possible to prove ground frame levers normal by means of contacts in the TBS line circuits. This would prevent the section being cleared with a ground frame incorrectly set, neatly replicating the prototypical feature whereby the block cannot be released if the ground frame is left unlocked.
 

The current standard mechanism for operating signals is a Maplin 12 Volt d.c. power relay. These are modified as follows:

• Bend the contacts apart slightly, to increase the travel of the armature

• Attach an arm made from a piece of Code 100 rail to the armature, to extend the travel

• Drill a large hole in the plastic cover for the arm to pass through

• Attach a mounting plate to the cover, for screwing to the baseboard.

Relay signal mechanism
 

Interlocked points (e.g. loop and siding entry points) are operated by one of two means:

• Directly by robust mechanical rodding from the lever frame

• Electrically by 12 Volt d.c. slow-acting electric machines (either Fulgurex or Lemaco).

In either case, the drive is taken by plastic covered galvanised garden wire to a substantial brass crank fixed under the points, where the throw is reduced to about half. A long steel pin in the shorter arm of the crank projects through a slot in the baseboard and passes through a hole in the fibreglass tiebar linking the point blades. A “joggle” is incorporated in the garden wire, to allow small adjustments to be made in situ with pliers.

Point machines use a standard 12 Volt d.c. 3-wire drive and correspondence circuit, with wiring details defined for each type of point machine.

Point machines are fitted with 3 pairs of detection contacts (Normal/Not Normal and Reverse/Not Reverse), which are used as follows:

               1 pair for motor current cut-off and correspondence circuit
               1 pair for traction current switching
               1 pair for detection in signal circuits

No facing point locks are provided.

It would theoretically be possible in future to use electronic presence detectors to replicate the operation of the economical FPLs.

A signal relay mechanism (l) and point machine (r) installed under a baseboard. The point machine drives the loop points and trap points, via the cranks at either end of the mechanism
 

Yard points are unlocked, and are individually operated by local switches via robust rodding. No detection of such points is needed in signal circuits, and the switch contacts control traction current.
 

Level crossings are released by a 12 Volt d.c. feed, switched in polarity, from the lever in the controlling signal box.
Level crossing gates are operated by a 12 Volt d.c. electric motor, via a mechanism that sequences the gates. The mechanism includes a correspondence circuit operating the lever lock, to prevent the controlling lever completing its movement until the gates have been operated and detection switches have proved the crossing gates closed to road traffic.
Local switch panels are provided near each crossing. These switch panels provide two modes of operation:

• In “Local” mode, the release from the signal box is indicated to the local operator by a “Open” (Green) indication, and replacement of the crossing lever in the lever frame by a “Close” (Red) indication. When an indication is present, the local operator may, in his own time, operate the gates using the “Operate/Halt” switch on the local control panel.

• In “Remote” mode, release of the gates by the signalman causes them to open, and replacement of the lever causes them to close. Operation of the “Operate/Halt” switch on the local control panel stops the gates moving immediately, in the case of an obstruction or fault.

Each crossing is detected closed to road traffic in the circuits releasing signals reading over that crossing.
 

All signalling is fed from a nominal 15 Volt a.c. power supply provided at each station. This supply is used directly by the tokenless block system, and is rectified and smoothed for use by the point machines and lever locks. Signalling power is normally fed from separate transformers from the traction power, to prevent momentary loss of signalling power during traction short circuits following derailments. However, the choice of 15 Volt a.c. means that, for testing purposes and for exhibitions, traction power and signalling power can be derived from a single controller.
 

It is very desirable to be able to continue to operate traffic following failures of the signalling system. The design philosophy addresses this issue by means of the following measures:

• Mechanical interlocking and rodding to points and signals, once adjusted, is regarded as inherently simple and reliable, and no special provisions are made to work around failures of such elements. “Joggles” are incorporated in rodding, to permit simple adjustment in situ.

• Electrical operation of points and signals is more prone to failures, mainly of electrical connections or of the adjustment of sensitive and inaccessible detection switches on the lever frame. Interim switch panels used prior to completion of fully interlocked lever frames are therefore retained for test purposes and for emergency use whilst lever frame faults are repaired.

• Failures of the block system can prevent the release of electric lever locks, and therefore prevent clearance of signals. Lever locks are therefore now designed to be operable manually, by lifting a pin, to permit signal clearance under such failure conditions.

The principal remaining vulnerabilities to signalling failure are as follows:

• Failure of the fragile soldered connections to point blades. These failures are relatively frequent, but are quite easily repaired in situ

• Risk of jamming of an electric point machine drive. There is currently no effective method for working round such a failure, although it has not been a problem to date.
 

Three main areas of improvement of the signalling are foreseen:

• As an interim measure, a simple relay circuit has been devised to permit signal clearance to be dependent on the TBS status on installations with unlocked switch panels. This will be added at Barnstaple Town as a trial in the near future.

• Lynton station is due for a rebuild (mostly scenic). At the same time, some small improvements will be done to the signalling.

• Completion of fully-locked lever frames for Barnstaple Town and Pilton. MSE parts have already been acquired to start work on Pilton. Perhaps a job for next winter….
 

The signalling contributes a lot to the overall appearance of a model. The various visible elements of signalling system are modelled carefully, just like any other aspect of the model.
 

Each of the three signal boxes on the L&B were different in design, and their construction is described site-by-site in the following sections. Generally, interiors are fitted to signal boxes, using commercially available whitemetal parts.

The signal huts at intermediate stations were quite rudimentary, and are scratchbuilt from thin ply and plastic sheet. The doors are left open, so that the tiny “knee” frame is visible within.

Ground frames are represented in the model, where their location is known from photographs (i.e. Pilton and Lynton), although the type of frame modelled is not necessarily 100% accurate.
 

The actual signal structures on the model represent the signalling as it was in the latter days of the line’s operation. There are a mixture of wooden post signals with lower quadrant arms, lattice post lower quadrants, together with a few typical SR rail-built signals – mostly with lower quadrant arms, but one (Woody Bay Up Home) with an upper quadrant arm.

Some signals have been completely scratchbuilt, with stripwood or Code 55 bullhead rail posts, and fittings fabricated from brass and nickel silver. However, the excellent Model Signal Engineering range of etched brass components have been used more recently. In particular, their lattice post parts cannot be beaten by scratchbuilding (I know, I tried – once). I have assumed that LSWR components are the most appropriate in terms of the style of arms, lamps, etc.
 

On the model, the functional point machines, signal relays and cranks are obviously installed well out of sight under the baseboards. To give the correct appearance on the model itself, non-functional point rodding, cranks, etc. are added to each layout, following the correct routes from the signal box to the points. On some sections, this rodding uses square steel wire running in tiny stands, assembled from etched brass components, between etched brass cranks, which were bought as a pack many years ago. More recently, I have used round brass rod (the L&B had round point rodding) running in stands made by drilling holes in small plastic “T” section material. When painted with rust colour, the effect is quite acceptable from normal viewing distance.
 

The L&B facing points were mostly fitted with fouling bars, unusually installed outside the running rails. As the lever for a set of points was moved by the signalman, the economical facing point lock mechanism caused the fouling bar to rise above rail head level as the lock disengaged, and fall again as the lock engaged after the points moved. Clearly, if a train was approaching the points, the fouling bar would be unable to rise, and the points would remain safely locked.

These fouling bars are represented in the model by a length of square steel wire soldered outside the rail head just below the upper surface, and a crude representation of the rodding is added.
 

Ratio plastic telegraph poles are installed on the layout, at the locations shown in photographs. These poles are cut down to give the correct number of insulators. In addition, based on photographic evidence, there are various places where insulators were provided on buildings, and even on a signal post, to allow telephone and tablet instrument circuits to reach the desired locations.
 

The signalling implemented on the model is currently as follows:
 

The overall architecture of the model L&B signalling is currently as shown in the following diagram:

Signalling power is derived from a single Radiospares 230V/15V dual secondary transformer housed in a box, via radial 15 Volt a.c. feeders to each station. Because of the use of a single transformer, connectivity between a.c. power sources and tokenless block circuits has been standardised, since otherwise it is possible to create short circuits via the TBS return conductor.

The transformer secondary windings have separate fuses; one secondary feeds Lynton and Woody Bay and the other feeds Pilton and Barnstaple Town.

The standard power supplies at each station include a series 15 ohm resistor, slightly reducing the voltage on the point machines to improve their life, and also limiting fault currents. The inclusion of these resistors means that points and level crossings should be operated sequentially.
 

The hand-built wooden post junction signals at Lynton were installed when the layout was constructed during the 1960s, but were not initially operational.

Lynton Up Starting Signals

Points were originally operated by solenoid point motors, which proved unreliable. The lever frame and mechanical interlocking was built around 1980, and was installed on the layout itself. The Tokenless Block equipment, block shelf and electric lever locks were added a few years later.

Mechanical operation of points and signals is by direct rodding from a hand-built lever frame next to the model signal cabin at the station. The lever frame incorporates mechanical interlocking between points and signals. Levers are not necessarily arranged in accordance with the prototype numbering (which is not known).

Lynton lever frame (l) with its Tokenless Block instrument, and the TBS relay set (r)

Traction switching is achieved via a single microswitch on each point lever in the locking frame. Signal On detection is via a similar microswitch on each signal lever. Due to the simplicity and robustness of the mechanical rodding, no local detection of point position is provided in signal controls.

Tokenless block for the single line section to Woody Bay is provided, with a block instrument on a block shelf behind the lever frame. The TBS interfaces to electric lever locks on starting and home signals.

The run-round crossover and goods yard points are locally operated by means of an unlocked 2 lever ground frame located next to the run-round loop.

The model of the small signal box at Lynton was scratchbuilt some 40 years ago.

Signal operation at Lynton has become unreliable, and some repair work is currently needed to render the home signals fully functional.

A minor change to the point control and the mechanical locking is also necessary to provide flank protection for passenger trains, to comply with the prototype. This error has emerged in the light of further research.

Signal lever locks may be replaced with the more recent standard design, to allow them to be manually released in the event of failure of the Tokenless Block system.

It is planned to relocate the ground frame for the run-round and goods yard points to the correct place at the end of the bay platform.
 

Scratchbuilt wooden post and rail-built signals were installed at Woody Bay when the station was built in the early 1970s, but they were not operational at that time. Points were originally manually operated by rodding.

The Woody Bay lever frame was constructed and commissioned during 2000/1, and the signals were made operational at this time.

Up end points are controlled by Fulgurex machines. No. 5 points (double-ended) have a non-standard arrangement for traction power switching (A end switched by N-/N switch, B end by R-/R switch), as the point machines have insufficient contacts for two sets of traction switching using the normal method using N and R contacts. This leaves the possibility of brief short circuits if the points are moved whilst trains are running.

Up end signals are motor-operated, using Fulgurex machines fed via local point detection contacts. This solution was adopted because, at the time, I had no suitable large relays to drive them, and experiments with Memory Wire, although promising, appeared to show the need for frequent adjustment to cope with temperature variations.

The down end points are controlled by a Lemaco machine. Down end signals are semaphores operated by modified 12 Volt Post Office 3000 type relays, whose contacts also provide the "signals on" detection interfacing to the tokenless block.

Woody Bay Up Home signal – the only upper quadrant on the line

A free-standing 7 lever Model Signal Engineering (MSE) lever frame is provided, with electrical switches for point and signal operation. Interlocking between points and signals is via a mechanical locking frame. The lever frame is connected to the station by two 25 way cables. Levers have the original L&B numbering.

Woody Bay Lever Frame. The TBS relay sets are behind the locking frame

Mechanical locking tray at Woody Bay, with electric lever locks (l)

Tokenless block is provided for the single line sections towards Lynton and Blackmoor.

The lever frame is modelled with the correct orientation, as per the prototype, where the signalman faced away from the track on the up platform (Lynton to the left, Blackmoor to the right). However, as currently installed, the model station is "the wrong way round", leaving the operator with Lynton on his right and Blackmoor on his left. This is not a serious problem, as the L&B lever numbering was not particularly logical (it may originally have been intended to provide distant signals approaching loops, rather than starting signals). The biggest difficulty is that the (non-prototypical) block instruments are at the "wrong" ends of the block shelf in this situation.

The signal hut at Woody Bay is scratchbuilt from thin ply.

Woody Bay Down Starter – an original Evans O’Donnell wooden post lower quadrant signal

Lyn passes Woody Bay Down Home signal – a tall rail-built lower quadrant

The Up starting signal and the Down Home signal, which are currently motor operated, will be converted to relay operation, to bring them into line with other stations, and to allow the point machines to be reused elsewhere.
 

Pilton Yard was built around 1980, and at that time all points were operated by individual toggle switches via mechanical rodding. No signals were provided at that time.

An interim switch panel was built in 2003, and outside equipment assembled and tested prior to its final installation in stages during 2004.

Outside equipment on each baseboard is connected to the lever frame by D-type cables. The Down end points and signal are connected by a 9 way cable, and the Up end points and signals via a 25 way cable to a distribution panel, from which three further 9 way cables link to Pilton Road crossing, Braunton Road crossing, and to the Down Home signals. A further connector is provided for eventual slots from Barnstaple Town (SR) Signal Box.

Signals, points and level crossings are all electrically operated from an interim lever frame consisting of 9 unlocked switches. This unit also houses the TBS and block instruments.

Pilton Interim Switch Panel, with block instruments

The Down end yard exit points are operated by individual local switches and rodding, rather than a ground frame. No electrical release or detection in signal controls is provided.

The Up end loop and yard exit points are operated by Lemaco point machines. The trap points at the up yard exit are non-functional, due to restricted space beneath the layout.

A MSE LSWR-type lattice semaphore Up Home signal is installed, and is operated, via a local point detection contact, by a modified Maplin power relay.

Pilton Up home signal. The dummy fouling bar is just visible to the left of the track

The Up Starting signal is constructed from an MSE lattice post with lower quadrant arm. It is operated by a modified Maplin power relay. This signal is actually attached to the fellmonger's yard scenic add-on that attaches to the front of the layout, and so it is plug-coupled to the main baseboard. The local point detection circuits allow the up starting signal to be cleared either for moves from the up loop or from the yard. With hindsight, this signal is a little too tall.

Pilton Up stating signal, with Pilton Road crossing in the background

The Down Home signal, with its main and shunt lower quadrant arms, is constructed from an MSE whitemetal "wooden" post, with rather complex platforms to allow access to the two lamps and arms. The shunt arm is provided with a black circle, although the use of such an arm appears to deviate from SR standards of the time. The red spectacle on this arm is of reduced diameter. Three groups of operating levers and balance weights are provided in an attempt to represent the slotting of these signals from Barnstaple Town L&B box. The main and shunt arms are operated by two modified Maplin power relays.

A train for Lynton passes Pilton Down Home signal; the second arm is for entering Pilton Yard

As Pilton had no down starting signal, it was necessary to simulate one, to allow the TBS to operate correctly. This was achieved by means of a relay circuit operated by the lever lock release.

As yet, there is no interlocking between points and signals at Pilton, although signal clearance depends on local point detection. Yard points are all operated by individual local switches at the front of the layout (actually in the mill leat!).
Mk2 Tokenless Block units are provided for the sections towards Barnstaple Town and Chelfham.

Pilton signal box is constructed using parts from a Ratio plastic kit, extensively modified to resemble the prototype as closely as possible. The interior includes models of the two Tyers No. 7A tablet instruments that, here alone, were located in the signal box.

Pilton Signal Box – the tablet instruments are the boxes with white indicators and brass plungers (top right)

It would be desirable to link the down end yard exit points, and control them from a single lever unlocked ground frame, similar to those provided for the quay siding and at Lynton, since the present switches are rather inaccessible (buried in the undergrowth!).

It is intended that the signalling will be controlled from a remote 9 lever MSE lever frame (i.e. a similar design to Woody Bay). The locking conditions for this lever frame have been defined and tested by simulation. More recently, advice has been sought from the specialist on L&B signalling about the most probable lever numbering for this lever frame.
 

Pilton Road crossing was constructed in 2003. It is electrically-operated by means of a Fulgurex point machine, with gates sequenced in pairs. Detection is provided by switches on the point machine itself.

The crossing is controlled from the interim switch-based lever frame at Pilton, via a local control unit hidden in bushes. Signal clearance is conditional on the crossing being proved open to trains.

The operation of the gates in pairs is not very pleasing, and the gates move too quickly. The crossing unit could be rebuilt with a mechanism like that at Braunton Road, as time permits.
 

A single lever unlocked ground frame is fitted. This is built from parts of an old GEM lever frame, and set into the surface of the yard outside Baker's Mill. The ground frame is (correctly) not detected in signal circuits.
 

The model of Braunton Road crossing was constructed as a removable unit during the 1990s, and incorporated in the loft layout more recently.

The electrically-operated fully-sequenced overlapping gates are driven from a single Triang X04 motor via double worm gearing. An arm rotates slowly round slots in four interlocked Perspex discs, which each move through 90 degrees in turn. Detection microswitches cut the motor power when the arm reaches the end of its travel. Each gate is driven from one of the Perspex discs by phosphor bronze wires and cranks. The drive method is a distant memory from the Meccano Magazine in my youth!

Top view of Braunton Road crossing mechanism with its overlapping gates

Underside of the same crossing. The brass arm rotates 360 degrees anti-clockwise to operate the gates

The crossing is controlled from the interim switch-based lever frame at Pilton, via a local control unit, allowing either remote control or remote release and local control. The control unit is housed in the doorway of North Gate House, adjacent to the crossing.

Signal clearance is conditional on the crossing being proved open to trains. To achieve this, a "Gates Open" detection relay is fitted on the operating mechanism to provide multiple contacts for local detection of the crossings in signal circuits.
The appearance of this crossing is most satisfactory in operation – one can almost imagine the crossing keeper walking round opening each gate in turn….
 

This station was constructed in a short period in 2003/4. Motor operation of the points and relay operation of the L&B starting signal were included from the outset.

Points are controlled by Fulgurex point machines located under the baseboard. Switches on these machines switch traction power to the track. The trap points on the run round loop and the transfer siding operate correctly in conjunction with the main points.

The down starter is constructed from Code 55 bullhead rail, with MSE components used for arm, platform, operating levers, etc. The model includes a representation of the operating lever providing the "slot" from the main line signal box. The signal is controlled by a relay mechanism based on a modified Maplin power relay.

The up home signal is not fitted, but a design has been prepared for a dummy colour light signal visible to the operator.

Initially, the station is controlled from a non-interlocked switch panel, which has been interfaced with Mk2 Tokenless Block equipment, although signal clearance is not currently dependent on TBS lever lock outputs. The lever numbers are arbitrary, as the original numbering is not known.

Provision has been made in the design for future slotting of signals at Pilton from Barnstaple Town SR signal box.

Barnstaple Town L&B signal box was unusual in having windows round all four sides. The model was constructed from the parts contained in two Ratio kits, extensively redesigned to represent the prototype. The result is quite pleasing.

Barnstaple Town Signal Box

The section of the standard gauge side of the station that is included in the model is purely static, has no points, and the down starter is merely painted on the backscene, as is the signal box for the swing bridge over the River Yeo.


Bob Barnard

barnard.bob@btinternet.com