Signalling Controls

Signalling controls named after locations.

Name	Description	Result of Accident
Angerstein Release	A very short pulse of voltage sent back the wrong way along the Locking Level of a GEC Geographical Interlocking to permit clearing of an outer backshunt signal. Aka the "squirt".	?
Balham Controls	A control in signalling that requires points in the flank to be set and locked, but only detected at time of clearance. This prevents a detection failure of flank points from putting back an already signalled route on the main. Can also refer, at a converging junction, to the protecting signal requiring not only track circuits clear in its own route but also one or more of those between the protecting signal and the junction of the converging routes, such that a SPAD at one of the other converging signals will immediately protect the junction. This is a form of over run control.	?
Brownes Lock	A lock that ensures that a sprung catch point is closed before a signal in rear of the catch point can be cleared up to a signal in advance of that catch, if the advance signal is at danger. This is only provided when the distance between the catch point and the signal in advance is less then the longest train that could be stopped at that signal. This lock ensures there is no risk of derailment for a train standing over these catch points. The signal in advance will require the catch points to be normal before it is allowed to be cleared (thus ensuring the catch points are effective). This control is very unlikely to be installed new, but is included for completeness.	?
Caterham Controls	Requiring of a trailing crossover at a terminus station to lie normally towards the departing line, in order that a runaway train or vehicle from the station will be directed onto a line in the sympathetic direction to its travel.	The 9.34am electric passenger train from Caterham to Charing Cross departed Caterham against the signal on 26 June 1945, colliding head-on with the incoming 8.55am electric London Bridge to Caterham, killing both motormen.
Colwich Controls	Preventing the display of flashing yellow junction indications unless the signal immediately beyond the junction signal is clear or ready to clear. This is in case the driver fails to recognise that the junction signal is maintained at yellow and does not step up to a less restrictive colour.	The driver of 86429 "The Times" on the 17.00 Euston-Manchester on 19 September 1986 mis-interpreted the flashing yellow junction sequence leading up to CH.28 as meaning the route was set throughout the whole junction complex (which it didn't and it wasn't) and passed the next signal CH.23 at danger, crashing into 86211 "City of Milton Keynes" on the 17.20 Liverpool-Euston which was legitimately signalled over the junction. 1 railwayman was killed and 75 passengers injured.
Foxhall Controls	Providing a position light junction indicator for the single route from a signal, where that single route applies through a set of facing points for the diverging route and track exists on the straight ahead route for which there is no legitimate signalled route (or it is of lower significance to the 'main' route). The provision of a junction indicator avoids the possibility of the driver believing they are heading 'straight on'.	Warship D853 "Thruster" overturned at 75mph on Foxhall Junction (25mph PSR) on 27 September 1967 wrecking the 9.45 Padd-Weston after mis-interpreting the green aspect with no junction indication in R.180 (and preceded by greens) as applying to the straight ahead route, when in fact it applied to a diverging route. R.180 not being fitted with a JI due to only having one main aspect route, that being the diverging route, with only draw-ahead aspects on the physically straight-ahead route. One passenger was killed and 23 injured.
Highland Loop Controls	Lighting of signals in loops only when a route is set towards them or a train is approaching them.	Prevalent in Scottish Region.
Huddersfield Controls	Preventing a train being signalled permissively into a platform when the platform starting signal is already off (and conversely, preventing the platform starting signal clearing if another train is signalled in permissively behind). Designed to stop the driver entering the platform permissively from reading-through to the platform starting signal.	Not named after a particular incident at Huddersfield, but that was the first place to be fitted at resignalling in 1958. Widespread implementation after an accident at Stafford when, at 00.30 on 4 August 1990, the 23.36 Stoke-o-T to Birmingham Soho entered the platform with a calling-on aspect, while ahead, in the platform, the 22.18 Manchester Picc - Penzance had a green signal to depart. The Birmingham train collided with the rear of the Penzance killing the driver and injuring 36.
Insell Locking	A means of holding a Signal in advance of a diverging junction signal at red where there is a risk of misreading or reading through.	-
Lime Street Controls	The checking by virtue of track circuits being occupied and clear, that there is sufficient room in a partially-occupied platform to accommodate a second train. Track circuits of a known length are provided in the platform line and in rear of the previous signal to achieve this.	On 31 July 1924 the 2.40pm Euston-Liverpool arrived on platform 7 at Liverpool Lime Street and crashed into a light engine that was standign half-way down the platform. The signalman was not aware of the light locomotive's presence. A recommendation from this accident was the fitting of track circuiting, which has since developed further into using track circuits to 'measure' trains.
Leatherhead Controls	An electrical equivalent to Sykes locking enforcing that a train must have passed a signal before the signal in rear can be cleared again, applied both between signals in the same signal box and through the block section.	Not named after an accident, Leatherhead was the first place the control was used.
Moorgate Controls	The progressive lowering of trip cock activation arms at pre-set intervals to ensure a train is slowing as it moves towards buffer stops.	A southbound Northern City Line train failed to stop at Moorgate on 28 February 1975 and crashed into the end wall of the tunnel, killing 43.
Morpeth Boards	The fitting of advanced warning boards and AWS magnets in connection with PSR boards at significant reductions in line speed.	The London - Aberdeen sleeper train overturned on a curve of only 17 chains radius at Morpeth after taking the 50mph curve at 80mph. Ironically, even though this accident lent its name to the fitting of such equipment to PSRs, the guidelines on the circumstances in which it should be fitted excluded Morpeth! A second accident at the same location, where the drunk driver of the Aberdeen - London sleeper overturned the trained at 85-90mph on 24 June 1984, finally precipitated the fitting of Morpeth boards and AWS magnets to this extremely tight curve.
Morton-on-Lugg Controls	Controls to retrospectively fit approach locking controls to level crossing barriers following the replacement of the protecting signal without the passage of a train. This has been necessary where the control is lacking following the 'like-for-like' replacement of manual gates (which had inbuilt 'natural' approach locking by virtue of their manual nature) with lifting barriers (which do not). (This control is sometimes also called 'Barrier Raise Inhibit Controls'.) The control has been tricky for the industry to fit, as it is largely required in mechanical areas, often with no track circuiting.	On 16th January 2010 an accident occurred at Moreton-on-Lugg level crossing that would have been prevented if approach locking had been fitted between the signal and level crossing controls.
Old Kent Road Controls	?	?
Raynes Park Controls	Ensuring that the contacts that allow an approach-released signal to clear are not so separate from the contacts that control the signal in rear to danger that a failure scenario could allow the approach-release to be satisfied and the junction signal clear while the previous signal showed green. So ensuring that the approach-release is not effective for the signal in rear to clear.	?
Rockcliffe Hall Control	?	?
Stowmarket Controls	Controls that cause a level crossing in very close proximity to a stop signal to start its amber and red light sequence when a train approaches (125m) the signal at danger, if they haven't already been called to lower.	?
Tollerton Controls	Providing overlapping train detection sections at the boundary between detection systems (eg, track circuits to axle counters) or interlocking types (eg, RRI to SSI), where the section to be occupied is slower to react than the section to be vacated. Can also be achieved with a time delay.	First identified at Tollerton. A little-known fact that York IECC has a relay interlocking in the Tollerton area which controls the auto sections there. (Better called a relay room as there is no interlocking of points and signals!) It was relatively new when the IECC was commissioned (formerly supervised by Tollerton box) and BR saw no reason to replace it with SSI. So it is a little island of relay-controlled signalling in a sea of SSI and hence the problems when trains transit across the boundary. The issue was no more than drivers receiving irregular step up / back down signal sequences when following another train, I don’t think anything actually happened.
Welwyn Controls	The preventing of sending of a second 'line clear' on an absolute block instrument until the berth track circuit of the home signal has become occupied and clear after the first 'line clear' OR a mechanical release release 'winder' has been operated. This avoids the possibility of a signalman giving a line clear in the belief a train has left the section when it hasn't and giving a second line clear.	On 17th June 1935 the signalman at Welwyn Garden City erroneously gave 'train out of section' for train 825A 10.53pm Kings Cross - Newcastle) to Hatfield No 3 when it had not arrived, and accepted train 826 (10.58pm Kings Cross - Leeds). Even though the signalman at Hatfield No 3 rang the signalman at Welwyn Garden City to enquire as to the suspiciously short time train on 825A had spent in the section, the signalman at Welwyn Garden City was adamant. As a result of the lack of locking preventing the block being cleared before a train arrives, an the signalman at WGC's inattention, train no 826 crashed violently into the back of train 825A, killing 13 and seriously injuring 29.
Wiltshire Distant	A 3 – 4 aspect transitional aspect sequence which utilises an isolated Y/YY/G signal to give full braking distances for all signals. This ensures that no single signal has both a Y and YY as a first caution for the subsequent signal.	Named after Philip Wiltshire.

Toton Signals - another name for 'creep' or 'unloading' signals in sidings.