By Adrian Allum with assistance from Tony Horne and Paul Webster, from a lecture on the subject given in November 1999; and published in “FLMJ-Nytt” (whole) and “Skandiapilen” (part).
Travel by train is probably the safest means of transport in any country. More people are killed in road accidents daily, than are killed in railway accidents annually. And yet, a railway accident puts the media into a state of vulgar hysteria, brainwashing many of their punters who are stupid enough to believe the first things that they are told. The fact is that on a train, everybody is at the mercy of two key people; the driver and the signalman. If either makes a mistake, the result of that mistake could be catastrophic. For many years, the signalman has had the advantage of ‘Interlocking’, a system that prevents him from setting up conflicting, diverging or converging routes when it is not safe to do so. Accidents caused by signal error are very few and far between. The driver, however, has very little protection. In the wake of the British accidents at Southall and Paddington, Automatic Train Protection was referred to by the media, especially as it does not exist in the UK (the AWS system hardly offers any protection – it is looked at in this report); but is plentiful elsewhere in Europe.
The Swedish Railways have a very reliable ATC system, and if it had been installed in Britain, neither of the accidents mentioned would have occurred. ATC means Automatic Train Control. It is a means of controlling the train if the driver’s concentration should lapse, so as to prevent an accident from resulting. ATP means Automatic Train Protection. Arguably, this is the same as ATC, but in technical terms, it is less efficient. ATP will, for example, stop a train if it goes past a signal at danger (SPAD / Signal Passed At Danger). ATC, however, will stop the train on its approach to a signal at danger, preventing it from actually passing it.
The British system is flawed with many inadequacies, and after the huge accident at Clapham Junction (1988) and a few that followed, it was recommended that a more comprehensive form of Automatic Train Protection should be provided. Thus, BR (British Railways – this particular undertaking now the responsibility of Railtrack) started to invent their own system. To quote a friend of the FLMJ, “They are trying to reinvent the wheel.” Such a process takes a long time, and in the meantime many more accidents are occurring. Railtrack needs to look at the effective systems in use on other railways around the world, and select one of them for the UK’s network. It would save money; it would save time; and it would save lives!
GOING WEST…
Before we look at the Swedish ATC, we will look at the system a little closer to the FLMJ’s members’ homes! ATC has existed on parts of the British railway network, but it was replaced by AWS (Automated Warning System) in BR days! The Great Western Railway included certain safety devices in their signalling equipment. One notable device was the track circuit control on the block telegraph instruments. A track circuit was installed between the distant and home signals and the block section to the rear could not be cleared until the train had passed the distant signal, operated the track circuit and passed the home signal. (Rear = behind a given point in the direction of travel. (Advance = ahead of the given point.)) This ensured that the line was clear to the home signal. (Incidentally, the first ‘track circuit’ in Britain was installed at Royal Oak, disappointingly close to the scene of the Paddington Crash!) Another notable device was the ‘Line Clear’ control on the starting signal. This prevented the signalman from clearing a starting signal unless the receiving signalman had accepted the train by giving the ‘Line Clear’. These devices, however, were not enough to prevent an accident at Shrivenham on January 15th, 1936. In this incident, a goods train became divided, and the marooned part was on an undetected section – before the distant signal (to the rear of it). Human error was the failure of the signalman to check for the presence of a tail lamp at the back of the goods train. Thus, the following train was accepted and the signals cleared, and the express sleeper train hit the obstruction at 55mph (90kmh).
Nevertheless, the GWR had an exceptionally good record for train safety, and they were keen to prevent a repeat of incidents that did occur. However, it was for assisting drivers in foggy conditions, not ATC, that the GWR made its first steps. It is difficult to imagine in today’s environment of smokeless zones, just how bad fog was some 70 years ago. Traditionally, ‘fogmen’ were called out to stand beside each distant signal. They fixed two detonators to the rail when the signal was at ‘caution’. When the signal was clear, the detonators would be removed. Fundamentally, this was wrong, because “no audible signal” could mean ‘signal clear’ or ‘fogman not arrived on site yet’ or even ‘fogman fallen asleep!’
It was Vincent Raven from the North Eastern Railway who designed and installed a ‘stop arm’ in the track, which was raised when the signal was at danger. It would then strike a lever below the cab, opening a whistle valve; thus an audible signal that did not rely on human correctness! However, again, there was no audible signal when the signal was clear – or the stop arm broken! A similar version of this is still in use on the London Underground.
The Stop Arms developed by Vincent Raven.
On the GWR, it was believed that this was not good enough. The driver also needed confirmation of a signal in the clear position. Around 1905, a new system of audible cab signalling was devised by the Signal and Locomotive Departments. There were three fundamental principles. There should be different audible signals for clear and danger; the device in the track should have no moving parts and not be physically connected to the equipment controlling the signal arm; and failure of the equipment should give the danger signal in the cab. The device that triggered off the signal was a ramp 4″ above rail level and about 40′-60′ in length, according to the line speed; and located anything between 200 to 440 yards to the rear of the signal. The top part (the contact making part) was electrically energised if the distant signal was clear, but dead when the signal was at caution.
A WR diesel locomotive with train. To the right, can be seen a GWR ATC ramp.
The moving part of this system was the plunger on the locomotive. The ramp was sloped at each end, and the plunger was raised every time it passed over the rail. As it lifted, it opened a small air valve, and on a dead section, it caused a siren to sound. If, however, the ramp was energised and electric current was picked up by the plunger, electromagnets in the locomotive’s equipment would be energised, closing the air valve, and instead, ringing a bell while the plunger remained in contact with the ramp. If there was a failure of the track equipment, the warning siren would sound; thus fail-safe.
A later modification was the arrangement of the air valve to let air into the brake pipe also, so that if no action was taken, the train would stop. The driver was required to acknowledge the audible signal whether in bad visibility or not.
In 1914, 180 miles of track and 90 locomotives had been equipped with the equipment. By September 1931, 2130 route-miles were equipped; and orders for up to 3000 units had to be placed with signalling contractors to ensure delivery in the time required. The GWR system was not liked by other administrations, many of whom favoured the transatlantic innovations with continuous rather than the intermittent control that the GWR had standardised. In fact, the incident at Shrivenham would not have been prevented by the GWR’s ATC!
In December 1937, there was a bad accident on the LNER (London North Eastern Railway (Operating northwards from Kings Cross station!)) in Scotland, during very bad visibility. During the enquiries that followed, a number of references were made to the GWR’s ATC, which it was considered would have prevented the accident. In March 1938, a special run was made from Paddington to Reading with a number of LNER officers as special guests, to demonstrate how the system worked. During the run, the driver was told to ignore a distant signal set in the caution position (i.e. Stop at next signal). It passed the signal at 69mph and the siren began to sound – but was not acknowledged. The train (a ‘Castle’ class locomotive and 10 coaches of 300 tons) stopped in 900yds on level track – 450yds short of the danger point.
THE EASTERN PROMISE.
The London, Tilbury and Southend system of ATC was similar. This was operated by magnetic induction. When the distant signal was at caution a permanent magnet on the track operated the apparatus, sounding a horn and applying the brakes after a short delay. Cancelling or acknowledgement by means of a handle provided, changed a visual indicator from black to yellow. If the distant signal was at clear, an electromagnet was energised, which cancelled the effect of the permanent magnet, allowing the horn to sound for a short time only and with no subsequent brake application.
Two magnets were fixed in the centre between the rails. The first contained a horizontal permanent magnet with its north pole at the trailing end, and the second contained an electromagnet. The tops of the magnets were 1″ above rail level. Additionally, permanent magnets were provided on the outlet roads from sheds to test the equipment before going into service. The motive power equipment comprised a magnetic receiver, horn valve, vacuum horn, brake valve, re-setting magneto and indicator.
THE BRITISH STANDARD…
The British Railways AWS also works on the principle of magnetic induction. When a distant signal is at caution, the permanent magnet operates the receiver on the motive power, sounding the horn and applying the brake after a short delay. Cancelling or acknowledging the indication by means of the handle provided, changes the visual indicator from all-black to black and yellow. If the distant signal is at clear, an electromagnet is energised, which cancels the effect of the permanent magnet and causes a bell to ring in the engine cab for a short period.
A BR AWS magnet.
Again, two magnets are fixed centrally between the rails. The first contains the permanent magnet with its south pole uppermost, and the second is the electromagnet. When the electromagnet is energised, (i.e., the signal is clear,) its north pole is uppermost. The tops of the magnets are at rail level. Again, some sheds have permanent magnets on the outlet roads to test the equipment before going into service. The motive power’s equipment is different, but the execution of its operation is similar. The receiver consists of a permanent magnet carrying contacts that act as a two-way switch, one contact being closed when the receiver has passed over a permanent magnet and the other contact being closed when the receiver has passed over a live electromagnet. The horn operates after a 2-second delay due to the solenoid becoming de-energised. Provided that the motive power is moving faster than 2mph, the contact for the bell will cut in before the solenoid becomes discharged. Quite simply the equipment on the train is repelled or attracted depending on the state of the electromagnet. There is no physical contact between the motive power and the track mounted equipment.
BR(M) did start to use transponders – in connection with higher speeds with the APT.
THE SWEDISH SYSTEM…
As a result of a number SPAD offences or failures to obey speed restrictions during the early 1970s, SJ invited tenders for the introduction of a nation-wide ATC system in 1975. At the same time, agreement was reached with the Drivers’ unions to dispense with assistant drivers (‘Second-men’ in English terminology)! This agreement was necessary due to an acute shortage of drivers caused by SJ’s erratic personnel planning, which meant that almost half of the driving force was pensioned off within 5-6 years. The agreement was also seen to be a natural efficiency improvement. This only served to speed up the introduction of ATC.
In the invitation, it was stated that the most common cause of railway accidents was ‘human error’, or as they put it – ‘a temporary lapse of concentration during an important moment!’ Of course, all moments in the cab of a locomotive are important. Nevertheless, the problem was identified and it is true to reflect that when incidents occur during the running of a railway, they do so with alarming speed and often with catastrophic results. Thus, in 1976, part of the Stockholm to Nynäshamn route was fitted with ATC; this being the 20km between Älvsjö and Handen; and also motive power in the shape of Rc4 1178 and X1 3103.
The system transmits speed and signal information from beacons placed between the rails. There are always at least two beacons at any given information point, the first giving an indication of direction. The other(s) transmit speed, target distance and signal information. The directional beacon is necessary because all lines in Sweden are bi-directionally signalled. Additional beacons will provide information about gradients within the braking distance etc. The equipment on the motive power consists of an ATC-aerial, an on-board computer, a cab display and electrically energised service brake and emergency brake valves. The information from signals and speed boards and so on, is passed via a track-side coding unit via signal cables to the beacons, which are activated by the passing ATC-aerial. This information is then interpreted by the on-board computer. If a train approaches a speed limit at too high a speed, the computer will, after an audible warning, initiate a braking sequence, which the driver cannot override until the train’s speed is below that of the targeted speed limit. With the passing of a ‘distant’ signal with a caution aspect (i.e., next signal at ‘Stop’), the computer will work out a braking curve, which the train must be below, or again the computer will after the audible warning, initiate the braking sequence. If the service braking distance is judged to be too short, this will result in an automatic emergency braking sequence to stop, before the brakes can be released. The results of the trials were very promising and it was decided to adopt the system on all trunk routes, and eventually all other routes also.
A track beacon – most beacons are yellow, though it would appear that they’re not colour-fast! An ‘Ra’ locomotive, showing clearly, the ‘pick-up’ between the bogies.
Following this decision, a number of serious accidents occurred as if to underline the human factor in the running of a railway:
- 1978 August 10th; An empty stock working collided head-on with a DMU after a SPAD outside Borlänge, resulting in 20 casualties and 11 fatalities.
- 1978 August 10th (again); ‘Camel’ DMU derailed at Stehag, between Malmö and Hässleholm on the Southern main line, after passing a 40kmh set of points at 120kmh. This resulted in 11 casualties and 4 fatalities.
- 1979 October 22nd; The overnight sleeper from Malmö to Stockholm derailed in Nässjö due to excessive speed through points at the station throat. The driver was killed.
- 1980 June 2nd; Head-on collision between a regional service and an empty stock working. There were a large number of casualties and 12 fatalities.
- 1980 August 18th; A Göteborg-bound InterCity service passed a signal at danger in Katrineholm and collided with a northbound train. Approximately 15 casualties.
- 1980 August 29th; Train 27 from Stockholm to Malmö ran through points set for 40kmh too fast. Half the train derailed. Unknown number of casualties, but no fatalities.
- 1980 September 23rd; A commuter service in the Stockholm area ran past signals at danger and through buffers. 15 passengers were injured.
- 1980 October 11th; The sleeper from Stockholm derailed due to high speed through permanent speed limit on the curve leading into Linköping, on the main line to Malmö. The driver survived, but 4 passengers were killed and 20 injured.
These accidents were caused by either SPAD or speed restrictions being ignored.
What happens when you don’t have ATC – a scene from a model railway layout at Gävle! [Photo: Adrian Allum.]
In 1980 large scale introduction of ATC protection started. First off was the Stockholm area, which has the most intensive rail traffic in the country. During 1981 the main routes, west to Göteborg, south to Malmö and north to Uppsala were complete, except for ATC-islands in the system at larger stations that required more time to install. At the end of 1985, all of the country’s major mileage was ATC protected, and since 1982 there has only been one serious accident due to a SPAD or failure to observe a speed limit. In 1990, on April 10th, the driver of a regional service lost his ATC information on the way to Sköldinge station on the main line to Göteborg. This was due to the on-board computer refusing to accept information from a failed signal beacon at the ‘distant’. He should have been warned that he should be braking to cross from the left-hand to the right-hand running line due to an engineering possession farther down the line. He missed this information and hit the points at 130kmh instead of 40kmh, resulting in 2 dead and 41 injured. The railway company stated that this was a case of negligence on the part of the driver. (It’s not just British railway companies that use their personnel as scape-goats!) However, after a lengthy legal tussle with the drivers’ union, it was agreed that this was indeed a case of ATC ‘blindness’, i.e., the driver only concentrating on the information presented by the cab display and not observing the signals he passes outside. Since then, drivers have been trained to react to beacon failure and certain functions of the ATC units have been modified. The train will now be braked to not more than 80kmh between stations and the driver must reduce speed even further when approaching a station or in a station to 40kmh.
The general layout of beacons and associated equipment.
Today, there are only a few ATC-islands, about 250 meters in the middle of Central Station in Stockholm, the last 500 meters of the route into Göteborg Central Station, and the Central Station areas of Sundsvall and Borlänge are perhaps the most notable amongst them. However, it must also be noted that where ATC protection ceases at these locations, running speeds of either 30kmh or 40kmh are enforced by the ATC system.
Warning to drivers of the end (Slutar) of the ATC area in the middle of Stockholm Central Station – 30km/h restriction in force! [Photo: Adrian Allum.]
Central Station – 30km/h restriction in force! [Photo: Adrian Allum.] Since the beginning of the 1990s the system has been upgraded to “ATC2” in order to provide a safer working margin following the introduction of the high speed X2000 services that run at a maximum of 200kmh. Although these trains have impressive braking characteristics, it was deemed necessary to provide more information to the driver, in order that he/she may plan their driving and provide a comfortable as well as safe ride for their passengers. Thus the upgraded system provides information not only about the next signal, but also the following ones by means of a ‘maximum speed ladder’ that can move with the train, depending on the state of on-coming signals, and preliminary advice about coming signals and speed restrictions can also be presented. A similar system is in use by Eurostar and other TGV services in France.
Recently, work has commenced on the installation of ATC on the 891mm gauge Roslagsbanan, a suburban commuter network running NE out of Stockholm. The ATC system being provided here is of the latest generation, with greater capacity than that used on the main line network; the information being transmitted through the rails instead of beacons.
On the Roslags Railway, there are no beacons; just wires to the rails! [Photo: Adrian Allum.]
In operation, ATC is impressive. The driver sets the parameters of the train via his cab display into the on-board computer. These parameters consist of the train length, braking percentage of the train, the time in seconds for a full braking application to take effect throughout the entire train, maximum permitted speed of the train on the given route or that of the slowest vehicle in the train (always the lower of the two – unless they are the same!), the percentage over-speed allowed for the particular unit (an X2000 is allowed 30%+, and Rc loco or an X10 is allowed 10%+ and so on) and the maximum brake force for a service application. Here it is possible to reduce the braking force by 33% during leaf-fall (Autumn) and heavy frost, thus avoiding costly wheel flats.
The ATC Panel in the cab, immediately below the window. A close-up of the ATC panel.
Most motive power and driving trailers have three identical on-board comparative computing units where two must always be in agreement, the third being in practice redundant in normal use. These units calculate a braking curve based on the parameters the driver has supplied and the information received from the signal beacons passed on route. Unlike many European systems that stop a train after it has passed a signal at danger, the Swedish ATC system will stop a train before it reaches a signal at danger. A friend of the FLMJ has reported on being invited (in his professional capacity) to try to take a train consisting of X1 and X10 commuter EMUs past a signal at danger during a demonstration. Despite believing that he had found a way of overriding the equipment, the train was still brought to a stand before the signal.
The ATC panel explained (from left to right). 1.Shunting mode, red lamp and switch. 2.Warning of approaching speed limit, yellow display. 3.ATC fault, red lamp. 4.Beacon fault, yellow lamp. 5.Speed too high, green lamp. 6.Current permissible speed, green display. 7.ATC braking, yellow lamp with release switch. 8.End of temporary speed restriction, green lamp and switch. 9.Brake pressure switch. 10.Passing signal at danger override. 11.Brightness control. 12.Volume control. 13.Driver information feed (reset), red lamp and switch. 14.Two thumb wheels = Maximum speed setting. 15.One thumb wheel = Train length. 16.Two thumb wheels = Full brake effect in seconds. 17.Three thumb wheels = Brake percentage. 18.One thumb wheel = Overspeed in % (1=5%, 2=10% etc / X2 = 6). 19 Minor fault lamp.
Possible risks with the system are still human error. Either a signalling technician feeding the wrong numbers into a beacon about speed and/or target distance to a signal or speed restriction, as was the case at Lerum (see below); or a driver entering the wrong information into his on-board equipment. One can speculate that in the future, the ITDC-link (Internal Train Data Communication) will also carry this information directly to the computer.
ATC was not able to prevent a collision at Lerum (on the Stockholm to Göteborg main line – about 20km east of the latter) on November 16th, 1987. This was caused by an incorrectly connected signalling circuit that gave the wrong point indication at the CTC (Central Traffic Control), causing a 110kmh train to cross into the path of an oncoming 110kmh train. Despite a closing speed of around 220kmh, only nine people, including both drivers were killed. No one person was found to be solely responsible, but a change in signalling re-wiring routines was enforced.
Another problem that does exist is the transmission of information from track beacons to the motive power. The present system works up to 350kmh and should the signal received not be precise or complete, the on-board computer will register a beacon failure. Depending on the type of fault registered, the train will either be automatically braked to under 80kmh, at which point the driver can override the system; or a full emergency brake to stop with no means of overriding will be applied, where the ATC treats the fault as an emergency. From my own experience, this latter course took about 30 seconds from 200kmh to zero – quite impressive!
Sometimes, during re-signalling work, it is necessary to disconnect the ATC system, using a beacon series that tells the on-board computer that any information picked up on route is to be ignored until a similar beacon tells it to do otherwise. During one such possession in the Stockholm area in 1993, there was a ‘SPAD’ in Älvsjö, putting a commuter service through a catch point and into a buffer stop on the safety track there. This incident was put down to the driver relying too heavily on the ATC, and not lineside signs and signals. Subsequently, such possessions are now kept to a minimum and are not allowed to run into many weeks, as was the case at Älvsjö.
There are other incidents that the ATC was unable to prevent. One was ice frozen onto the disc brakes. The driver made an emergency brake application (and this was confirmed by the ‘black box’ after the incident), but there was no braking effect until too late! One driver was killed last year during a shunting operation. He was using the remote control and went between the two rakes of goods wagons to couple them together; and slipped – hardly a problem that ATC could prevent!
There has also been a problem, that if a signal changes from a cautionary aspect to clear, it may go through a short red aspect – the equipment registers “Bulb Failure” and puts the signal to stop, momentarily. If the ATC-aerial on the motive power is directly over the beacon when this happens, the on-board computer will register SPAD and an emergency stop will follow. This problem has now been largely cured with signalling equipment being renewed throughout the country. Further, should the ‘ATC through the rails’ system be adopted and beacons become obsolete, changes in condition would show up on the cab display as soon as they occur and not when the train passes the next beacon. This practice can be developed further to the introduction of ‘Moving Block’, but that’s another story…
Swedish railway safety is profound. Rail is the safest form of travel in Sweden, and since the Sköldinge accident (ten years ago), SJ hasn’t lost any passengers. SAS (Scandinavian Air Service) has (although ‘statistics’ will show otherwise), and the annual death toll on Swedish roads is roundly 500.
X1 3075 and two track beacons.
Latest on the UK scene…
The TPWS (Train Protection Warning System) is to be installed on the UK network by 2002. TPWS is an extension of the AWS, providing train-stop and overspeed sensors. The TPWS monitors the train 300 meters before key signals (i.e., those that have been equipped with the system – protecting junctions, single lines and at places where ‘unusual’ train movements are frequent); and sensors are fitted to the trains. If the train runs between the two radio loops laid on the track in front of a signal showing red, at a speed that suggests it is not going to stop, the TPWS will ‘spike’, causing the train to be stopped; taking the control away from the driver. If the train is travelling at below 75mph (120km/h), it will normally be stopped within the 200meter overlap beyond the signal. If the speed is greater, the train cannot be stopped within this distance, but its speed will be slower – reducing the seriousness of any impact! TPWS is quite simply a very cheap and quick alteration to the existing system! The system is not designed to prevent SPAD – only to stop trains once they have gone past a signal at danger.
The ATP facility in the UK has been fitted to Heathrow Express trains, and some other routes out of Paddington and Marylebone. It is also to be fitted to the West Coast Mainline (out from London Euston) and the East Coast Mainline (out from London Kings Cross). In essence, the functions of the ATP are similar to the Swedish ATC, and this makes it far safer; however, Railtrack appears to disagree! They have produced figures to show that TPWS will offer as much as 70% of the benefit of ATP, but at 10% – 15% of the cost! Also, it would take at least ten years to install ATP, making the provision of a safer railway longer into the future. However, although TPWS has been selected for the UK, Railtrack has stated that it does intend to install ATP on all new routes as part of re-signalling schemes. The ATP on the lines out of Paddington and Marylebone, however, do not conform to European requirements for new installations of such equipment on high speed lines. There is more about this (in conjunction with the Ladbroke Grove Rail Inquiry).
ATC IN H0-SCALE…
ATC can be applied to model railways also, but using different technology. A simple detector in the track will isolate the train if it comes alongside a signal at danger. Used in conjunction with cab-control, a more sophisticated system can be deployed; one which ‘connects’ sections as they are approached and disconnects them afterwards. Thus a controller is connected to only the track where the train is standing, and from then on, the sections are connected as described. A signal at danger is not passed due to the detector as used above. With cab-control, direction can also be monitored, as well as speed! It is understood that the new FLMJ (and Köpingsvik) will have some form of ATC!
As a footnote, ATC has been installed on a privately owned 184mm gauge miniature railway, using the rails to transmit the information. Apart from the obvious detectors that pick up the information, the only modifications to the motive power are the fitting of extra brake valves and ITDC connections. This railway uses only vacuum fitted stock, and the ITDC prevents the wrong information being keyed in by the driver. The cab panel is a loose mounted box, positioned by the driver to suit his comfort, and the only button is to ‘reset’ the equipment whenever needed. Two of the locomotives have had other modifications to close the regulator and open the blower whenever the ATC takes effect! (If the regulator is closed with the blower closed, there is a risk of the fire blowing back into the cab!)
Feedback…
We have received a letter concerning the British and European ATP systems. It is most informative, though anonymous, and we publish it here…
“Whilst the introduction of ATP, in Britain, was recommended by Sir Anthony Hidden’s Report into the Clapham Junction railway accident on 12/12/88 (Recommendation 46: “…After the specific type of ATP system has been selected, ATP shall be fully implemented within 5 years, with a high priority given to densely trafficked lines”); ATP linked with the existing signalling system would not have prevented the disaster which claimed the lives of 35 people, as it was caused by a wrongside signalling equipment failure. On the 12/12/88, Signal WF138 displayed a green aspect, instead of a red, due to a short circuit caused by a loose wire. As no signal passed at danger (SPAD) occurred; ATP, like the Driver of 06.14 Poole – London Waterloo train, would have registered a green aspect and the three train collision would still have occurred.
Following the accident, two European ATP systems were installed on the UK rail network, as part of trials to evaluate which system was most suitable to the UK’s needs, which would be compatible with the UK signalling systems.
On the Great Western lines out of London Paddington, an inductive transponder system – known as Belgium Railways (SNCB/NMBS)’s Transmission Balise Locomotive (TBL) was installed. This uses trackside beacons and light grey “shoeboxes” in the ‘fourfoot’; and can still be seen today.
On the Chiltern lines out of London Marylebone, a system known as German Railways (DBAG)’s Indusi (Induktivzugsicherung) was installed. This is the simpler form of ATP used on lower speed routes in Germany; and it can be seen as black “wiggly-wire” in the ‘fourfoot’ on the approach to various controlled signals. For the Neubaustrecke (purpose built ICE routes), DBAG uses their LZB (Linienzugbeeinflussung) system.
The above illustrates some of the problems associated with some forms of ATP. The Belgium TBL is now in its third / fourth generation. As SNCB/NMBS installed it first on their higher speed routes; the most advanced form has ended up on the remaining lower speed, lower density, lower risk routes. While DBAG has had to use two systems to cover their network.
This is further complicated by the fact that it was not until the year 2000 that an European ATP standard system was agreed, or at least agreed in part. The favoured system is the Swedish ATC system designed by Adtranz. Neither of the two systems mentioned above are compatible with the European ATP standard system, which will be known in the UK as European Rail Traffic Management System (ERTMS).
Meanwhile, following the Southall and Ladbroke Grove railway accidents, the British government using the Railway Safety Regulations 1999, mandated the fitment of Train Protection Warning System (TPWS), which is the UK form of ATP which provides both a train stop and an overspeed sensor. The Regulations require the fitment of TPWS by 2003, and this is likely to be achieved by 2002, one year ahead of Statute.
In Europe, the railways vary considerably in terms of loading gauge, axle load, electric traction supply voltages, signalling systems and ATP. Some countries have certain passenger lines without any form of AWS, ATP or ATC, e.g., in Italy, on non Eurostar-Italia routes, conventional Italian Rail (FS) trains use double-manning of drivers. Linesmen with flags in southern Portugal are used on some Portuguese Rail (CP) routes. Some countries have “speed signalling” (e.g., a “Carre Violet” on SNCF lines in France means “speed must not exceed 30 km/h”) while others use “route signalling” (i.e., the UK, where a Route Indicator which line the train will transverse, and the Driver uses his / her Route Knowledge to know what speed to drive at). Some railways operate on left hand running, while many Germanic / Scandinavian countries use right hand running.
Indeed, some countries, i.e., Ireland, have successfully reduced / eliminated SPADs without using ATP. Iarnrod Eireann (Irish Rail) use a combination of Continuous Automatic Warning System (CAWS) and tripcocks. CAWS varies from the UK’s AWS in that is shows the driver four signal aspects, not just Green / Non Green (without differentiating between two yellows, one yellow or red) as in Britain. CAWS was developed from the UK’s Southern Railway AWS (SRAWS). Unlike the London Underground which permits a “stop and proceed at caution rule”, to pass raised tripcocks (and the failure to observe the “caution” part of this Rule resulted in 12 people dying at Stratford (on the Central Line) on 08/04/53); both UK and Irish Railways require Drivers to obtain the signalman’s permission.
According to a ERTMS presentation given by Adtranz, not all European countries wish to adopt the new standard. Norway (NSB), Luxembourg (CFL) and Ireland (CIE) have currently indicated to Adtranz that they will not be installing ERTMS. There are also three levels of ERTMS:-
- Level 1 – ATP with intermittent communication,
- Level 2 – ATP with continuous communication and reduced trackside hardware, and
- Level 3 – ATP with minimised trackside hardware, radio communication and centralised interlocking (RBC).
Lastly, it would be wrong to think that the only anti-SPAD device on the UK footplate is AWS. To combat the large proportion of SPADs which result from “Starting Against Signal”, the Driver’s Reminder Appliance (DRA) is used, which isolates the traction supply. The idea is to prevent drivers being misled by the “Right Away” given by platform staff or the train guard; or by themselves overlooking the red signal after completing platform duties on a Driver Only Operated (DOO) train, etc. “Ding-ding and away SPADs” have resulted in 7 dead at Paisley Gilmour Street on 16/04/79 and 2 dead at Bellgrove on 06/03/89.
Additionally, the “Deadman’s Handle” has been upgraded to the Driver’s Vigilance Device; whereby a driver has to make a conscious decision to depress a foot pedal, release it and re-apply pressure within a set timescale to prevent an automatic brake application. The faster the train goes, the shorter the response time allowed. This has the advantage over the Deadman’s Handle of not being mechanically defeated by the driver weighing it down artificially, i.e., by hanging a driver’s bag on it.
Finally, the crashworthiness of rolling stock also has a part to play in mitigating injuries following SPADs. The Railway Safety Regulations 1999 also require the withdrawal or modification of all remaining Mk.1 stock on the UK network by 2003. It was interesting to read in the press about the TGV Nord train which derailed at 186mph (300km/h), and there were no fatalities or major injuries.”
Anon.