Greg Morse

In Septem­ber 1997, a fa­tal col­li­sion oc­curred af­ter a sig­nal was passed at dan­ger at Southall. GREG MORSE looks at the causes - both im­me­di­ate and un­der­ly­ing - and asks what the in­dus­try is do­ing about SPADs 20 years on

Rail (UK) - - Contents -

“Har­ri­son rammed on the brake. There was noth­ing more he could do. He left his seat and hid be­hind the bulk­head door. By the time he emerged again, his train would be in dis­ar­ray - six peo­ple would be dead.”

Nine miles out. Nine miles from Padding­ton. You wouldn’t know as you passed to­day, your train cruis­ing at a hun­dred or so as it comes into the cap­i­tal from Truro or Taun­ton, West­bury or We­ston-su­per-Mare. You wouldn’t know as Southall flashes by, and you glance over at the old de­pot to glimpse

Bod­min or Sir Nigel Gres­ley steam­ing up, or a ‘47’ or ‘33’ stand­ing by. Twenty years ago it was dif­fer­ent - 20 years ago the out­look was darker.

Sup­pose it’s 1997… Fri­day Septem­ber 19. You’re on the 1032 from Swansea, and you’d had a pleas­ant enough time of it since you got on at Read­ing. No prob­lems, no wor­ries, just you and your pa­per sit­ting qui­etly by the win­dow some­where near the back in Stan­dard Class. There had been a bit of slow run­ning - speed re­stric­tions, you’d pre­sumed (rightly) - but Slough had slipped by, so had Lan­g­ley, so had Iver, West Dray­ton, Hayes & Har­ling­ton.

You felt the train was per­form­ing well. You couldn’t know its pro­tec­tion sys­tems weren’t work­ing, couldn’t know the sig­naller back at Slough was set­ting a route for a train of empty hop­pers to cross over in front of you. Your driver hadn’t banked on it ei­ther…

At around 1310, Larry Har­ri­son started pack­ing up his holdall with his di­a­gram and notices.

Round­ing the left-han­der ahead of Southall, he sud­denly saw a red sig­nal ahead. As the lines straight­ened in front of him, he saw some­thing else - a Class 59 at what he’d later de­scribe as ‘a funny an­gle’. A col­li­sion was in­evitable.

Har­ri­son rammed on the brake. He knew there was noth­ing more he could do. He left his seat and hid be­hind the bulk­head door. By the time he emerged again, his train would be in dis­ar­ray, six peo­ple would be dead (with an­other soon to join them) and 139 would be in­jured. By seven that evening, he’d be ar­rested, too.

Many of the pas­sen­gers were jour­nal­ists re­turn­ing from a vote on Welsh de­vo­lu­tion. One, BBC re­searcher Nick Sut­ton, said that as he left the train, he “saw a body ly­ing by the side of the tracks. No one was touch­ing it. His shirt was ripped and there was blood all over him ... Ev­ery­one was shocked.”

Dr Michael Hel­lier, from Ald­bourne in Wilt­shire, suf­fered cuts to his head and al­most lost an eye. He told re­porters how there’d been “a tre­men­dous bang and ev­ery­thing went black”. “Some­thing hit me very hard on the head,” he added. “I was thrown across the com­part­ment as the coach rolled over, and my first thought was that I was dream­ing. Then I re­alised it was not a dream.”

It wasn’t: the lead­ing power car had ploughed into the side of the freight train’s sev­enth hop­per, be­fore strik­ing the eighth and suc­ces­sive wag­ons, caus­ing them quickly to de­rail.

The lead­ing coach be­came de­tached, fell on its side and slid along the bal­last be­fore col­lid­ing with an OLE mast. The sec­ond coach struck the rear of the freight, the im­pact lift­ing it and the last wagon into the air be­fore the lat­ter was trapped by an­other mast, caus­ing it to come down on the former, which was

in turn jack-knifed by the mo­men­tum of the coach be­hind.

In­side half an hour, around 100 res­cue work­ers had reached the scene. Air am­bu­lances took the se­ri­ously in­jured to hos­pi­tal, while fire­fight­ers quelled the flames in front of and be­neath the HST, be­fore mov­ing in with cut­ting equip­ment to free the 16 who were trapped. One res­cue worker mar­velled that more hadn’t been killed, such was the dam­age caused to the car­riages. Andy Reynolds, As­sis­tant Di­vi­sional Of­fi­cer with the Lon­don Fire Brigade, called it “a scene of com­plete car­nage”.

Deputy Prime Min­is­ter John Prescott was soon there to of­fer his con­do­lences to the rel­a­tives and friends of the dead. “I have talked to the Rail­way In­spec­torate,” he said. “They have in­spec­tors on site and will make a de­tailed ex­am­i­na­tion to es­tab­lish why the ac­ci­dent hap­pened. I have asked for an ur­gent re­port on the crash. In the mean­time, if there are any im­me­di­ate lessons to be learned, we will of course take the ap­pro­pri­ate ac­tion in the in­ter­ests of safety.”

Jimmy Knapp, leader of the RMT union, de­manded that the in­quiries con­sider whether the frag­men­ta­tion of the rail in­dus­try had been a fac­tor, this be­ing close to the end of the pri­vati­sa­tion process that split one com­pany into over a hun­dred.

Rail­track’s Chief Ex­ec­u­tive John Ed­monds kept his op­tions open. “We are con­tent pro­fes­sion­ally that we have a proper sys­tem of main­te­nance,” he told the me­dia. “But clearly there has been a ma­jor fault some­where. It’s con­ceiv­able there was a tech­ni­cal fail­ure and it’s also con­ceiv­able there was a hu­man er­ror.” His words were to prove more prophetic than he prob­a­bly re­alised.

A spokesman for the Bri­tish Trans­port Po­lice said Har­ri­son had at­tended Southall Po­lice Sta­tion vol­un­tar­ily, passed a breathal­yser test and was in­ter­viewed be­fore be­ing re­leased on po­lice bail. He had been ques­tioned in con­nec­tion with man­slaugh­ter charges, but not ac­tu­ally charged. Alan Bricker, the driver of the freight train, was also ques­tioned be­fore his re­lease.

As Rail­track in­spec­tors be­gan to ex­am­ine the wreck­age, it was an­nounced that the Health and Safety Ex­ec­u­tive (HSE) would hold a pub­lic in­quiry. As the play­ers gath­ered to play their parts, there was spec­u­la­tion about the sig­naller route­ing a train across the path of an ex­press, as well as spec­u­la­tion about Har­ri­son af­ter it was re­ported that he’d been spot­ted pulling in to Bris­tol Park­way with both feet on the driv­ing desk.

The prob­lem for Har­ri­son was that while his record was ex­cel­lent - un­blem­ished bar a cou­ple of slow-speed SPADs (Sig­nals Passed at Dan­ger) in the 1970s and an in­ci­dent in 1996 when he’d set off with­out the ‘right away’ - he had not only passed SN254 sig­nal at red, but had also un­heeded SN270 (yel­low) and SN280 (dou­ble yel­low) in the run-up. In the fol­low­ing April, those man­slaugh­ter charges would re­turn.

By this time, the pub­lic in­quiry pro­ceed­ings had be­gun. Chaired by lawyer, ar­biter and aca­demic Pro­fes­sor John Uff QC, it would re­veal the ac­ci­dent to have been - to some ex­tent - “clas­sic James Rea­son”. Rea­son had the­o­rised a com­pany or in­dus­try’s de­fence mech­a­nisms against fail­ure to be a se­ries of bar­ri­ers, but they - like slices of Swiss cheese - usu­ally have holes or hith­erto un­recog­nised weak­nesses in them. When all the holes in each of the slices align, it cre­ates a “tra­jec­tory of op­por­tu­nity”, al­low­ing a haz­ard to pass through to an ac­ci­dent.

Most ac­ci­dents are thus multi-causal. In this case, while the ‘SPAD’ was clearly the “im­me­di­ate cause”, there would have been sev­eral un­der­ly­ing causes, the ab­sence of some or all of which might have pre­vented the col­li­sion from oc­cur­ring re­gard­less of Har­ri­son’s fi­nal act (or in­ac­tion).

That said, Uff spent many pages de­lib­er­at­ing the driver’s be­hav­iour… and the weight of his bag. The is­sue here was that the bag could have been used to hold down the driver’s safety de­vice (DSD) pedal - at least it could, ac­cord­ing to the Bri­tish Trans­port Po­lice. Har­ri­son chose to use a sports bag in­stead of the smaller ‘rail­way is­sue’ used for car­ry­ing Bardic lamps, hi-vis vests, notices, keys, food and so on. The bag re­cov­ered af­ter the crash was “found to con­tain two cans of fizzy drink and a rail­way is­sue metal vac­uum flask, to­gether with a jar of tea bags”.

Har­ri­son’s pref­er­ence “was for de­caf­feinated tea”, the re­port went on. “Why, then, did the bag also con­tain soft drinks?” Har­ri­son said he “oc­ca­sion­ally pre­ferred this when he wanted a long drink”.

Uff wrote that the ex­pla­na­tion seemed “plau­si­ble enough”, although some in­ves­ti­ga­tors had been con­cerned that he had de­lib­er­ately weighted the bag “in or­der to be able to use it to hold down the DSD pedal”, which would have left him “around 55 sec­onds be­tween pulses”, dur­ing which “he could stand up, stretch and carry out other ac­tiv­i­ties in­con­sis­tent with keep­ing a proper look­out”. The trou­ble was the bag wasn’t heavy enough to de­press the pedal or even hold it down.

In the event, the in­quiry con­cluded that there wasn’t enough ev­i­dence that Har­ri­son had been “de­lib­er­ately mis­us­ing the train”. In­deed, the “most likely ex­pla­na­tion” was that “he was in­vol­un­tar­ily inat­ten­tive ei­ther for

The HST was also fit­ted with Au­to­matic Train Pro­tec­tion (ATP), although as it was not func­tion­ing that day, ar­guably it might as well have not been there.

two pe­ri­ods of seven and ten sec­onds or for one longer pe­riod, suf­fi­cient to pass sig­nals SN280 and 270” with­out ob­serv­ing, or at least reg­is­ter­ing, their as­pects and mean­ing. It was pos­si­ble that Har­ri­son had been “lulled into inat­ten­tion be­tween the reg­u­lar pulses of the DVD”. He may in­deed have “mi­croslept”.

Why so much spec­u­la­tion? Har­ri­son had done him­self no favours in driv­ing with one foot (or two) up on the desk. It was a rash thing to do, it had rat­tled the pas­sen­gers who’d re­ported it, and it lent some weight to the need to con­sider the mat­ter more fully. It was un­wise, it was un­pro­fes­sional, but it didn’t make him a crim­i­nal - par­tic­u­larly not when there were many sys­temic fail­ings also con­tribut­ing to the ac­ci­dent.

Take the sig­nals, for ex­am­ple. As Stan­ley Hall pointed out in Hid­den Dan­gers (1999), long-range sight­ing of SN280 was “re­stricted by an over­bridge at [Hayes & Har­ling­ton] and the gen­tle left-hand curve of the line”, while SN270 was “grossly mis­aligned”, be­ing “fo­cussed into the ground ap­prox­i­mat­ley 90 yards from the sig­nal in­stead of at driver’s eye level 220 yards away”. Hall says the beam of the lat­ter’s sin­gle yel­low would have been in

Har­ri­son’s view “for less than one sec­ond at the speed at which he was trav­el­ling”.

The in­quiry dis­agreed, cit­ing ex­pert tes­ti­mony - and three driv­ers whose trains pre­ceded Har­ri­son’s on the day of the ac­ci­dent (all of whom saw all the sig­nals in ques­tion, at green). “In the light of this ev­i­dence” (in­ter alia), wrote Uff, “it ap­pears to be the case that sig­nal SN270, while in­cor­rectly aligned, was ad­e­quately vis­i­ble […] to a driver keep­ing a proper look­out”.

Re­gard­less of Uff, we have a sit­u­a­tion in which driver inat­ten­tion cou­pled with less than op­ti­mal sig­nal sight­ing (in at least one case) may have com­bined. Add now a change in traf­fic em­pha­sis. In BR days, says Chris­tian Wol­mar in On

the Wrong Line (2005), “high-speed pas­sen­ger trains al­ways had pri­or­ity over goods trains, which some­times sat in sid­ings for a long time be­fore be­ing al­lowed to pro­ceed”. The first post-pri­vati­sa­tion reg­u­la­tor changed that “af­ter con­sul­ta­tion with the in­dus­try” to cre­ate “a sys­tem of min­i­mum over­all de­lay”. There was scant ev­i­dence that this pol­icy change af­fected the course of events on Septem­ber 19 1997, and Uff was un­able to con­clude it to have had any safety im­pli­ca­tions.

The story of train pro­tec­tion in Bri­tain be­gan with a fa­tal SPAD and col­li­sion at Slough on June 16 1900, the most dis­turb­ing thing about which be­ing not that the driver hadn’t obeyed the sig­nals, but that he couldn’t ex­plain why. In re­sponse, the Great West­ern Rail­way de­vel­oped ap­pa­ra­tus that would sound a bell in the cab if a Dis­tant sig­nal was ‘clear’ and a siren if it was at ‘cau­tion’. This recog­nised that - as trains were get­ting faster - dis­tant sig­nals were be­com­ing more im­por­tant, as they gave driv­ers ad­vance warn­ing of the need to start slow­ing for a Stop sig­nal up ahead.

Tri­alled in 1906, the equip­ment was later de­vel­oped so that if a driver passed a Dis­tant at ‘cau­tion’ and failed to ac­knowl­edge the warn­ing, the brakes would au­to­mat­i­cally ap­ply. In this form, what be­came known as Au­to­matic Train Con­trol would be fit­ted to 3,250 lo­co­mo­tives and 2,850 Great West­ern track miles by 1939.

On na­tion­al­i­sa­tion in 1948, Bri­tish Rail­ways in­her­ited all those ex-GWR miles, along with 37 be­tween Lon­don and Southend, on which the LMS had in­stalled a sim­i­lar set-up, ac­ti­vated by mag­netic in­duc­tion. Seek­ing to make progress, BR en­tered into sev­eral stud­ies, ex­per­i­ments and tri­als to find the form its own ver­sion should take. ATC was favoured at first, but its need for me­chan­i­cal con­tact was thought to be a dis­ad­van­tage at high speed. There was also a pos­si­bil­ity of stray earth re­turn cur­rents in elec­tri­fied ar­eas lead­ing to the equip­ment giv­ing a false in­di­ca­tion.

It was there­fore de­cided to adapt the LMS sys­tem, although it proved very dif­fi­cult to make the de­sired mod­i­fi­ca­tions and the de­sign was not fi­nalised un­til Au­gust 1952. Be­fore the first test run could be made, its value was demon­strated by a SPAD and a multi-train col­li­sion at Har­row & Weald­stone (Oc­to­ber 8 1952), an ac­ci­dent that claimed 112 lives.

The in­ves­ti­ga­tion con­firmed that the ‘SPAD’ train had passed the colour-light Dis­tant at ‘cau­tion’ and two sem­a­phore sig­nals at ‘dan­ger’. BR was urged to con­tinue with its ‘Warn­ing Con­trol’ pro­gramme, hav­ing al­ready an­nounced that (as soon as the equip­ment was work­ing sat­is­fac­to­rily) it would launch a five-year plan to fit 1,332 miles of main line, with a fur­ther 4,000 miles ear­marked for the longer term.

‘Warn­ing Con­trol’ (or AWS, the Au­to­matic Warn­ing Sys­tem) was fit­ted be­tween King’s Cross and Gran­tham in 1956. By 1960 it had reached York, and would soon spread to other routes. In time, it would help re­duce the num­ber of fa­tal­i­ties in train ac­ci­dents. It would have saved the lives lost at Southall. The trou­ble was, it wasn’t work­ing that day in 1997. Why?

A fault had oc­curred in the lead­ing power car (43173), when ar­riv­ing at Ox­ford the evening be­fore. Hav­ing been tripped by the ‘red’ at the plat­form end, the AWS brought the train to a stand part-way along. The driver was un­able to re­set it, so he iso­lated it and was given per­mis­sion to take the set on to Padding­ton.

The trou­ble was the fault was never dealt with. At Ox­ford, the driver told the sta­tion su­per­vi­sor, who told the sig­nal­man that the brakes had come on, but not why. This meant the fault didn’t get passed to Op­er­a­tions Con­trol, Swin­don, which would have meant it be­ing logged in the Rail Ve­hi­cle Records Sys­tem (RAVERS), thereby bring­ing it to the at­ten­tion of Old Oak Com­mon.

The driver did make an en­try in 43173’s ‘fault book’, but when he took the train ECS to the de­pot, he didn’t fill in a de­fect re­port or an in­ci­dent re­port form - ei­ther would have plugged the gap left by the ‘comms’ er­ror and made sure the fault ended up in RAVERS. As it was, the only record of 43173’s AWS prob­lem was in that book, a book to which the fit­ters came late as they had other faults to deal with.

Old Oak had been re­or­gan­ised af­ter GWT took it over in Fe­bru­ary 1996. Staff num­bers had been cut and (as Uff put it) the men “were work­ing un­der more pres­sure, and can­not have been mo­ti­vated to spend more than the min­i­mum time nec­es­sary to carry out

The ac­tion of the sig­naller in stop­ping an ex­press to al­low a slow freight to cross in front of it was crit­i­cised.

etc 1974 that it had failed to en­sure “that the pub­lic were not ex­posed to risks to their health and safety”. It was fined £1.5 mil­lion.

The ac­tion of the sig­naller in stop­ping an ex­press to al­low a slow freight to cross in front of it was crit­i­cised, and the de­lay min­imis­ing pol­icy that had al­lowed it was re­versed by Tom Win­sor (as Reg­u­la­tor) in Novem­ber 2000. The fact that there was no re­quire­ment for the sig­naller to have been in­formed that the HST was in ser­vice with its AWS iso­lated was dealt with by a Rule Book amend­ment that re­mains to this day.

An­other key point iden­ti­fied by Uff was that driv­ers had be­come in­creas­ingly re­liant on AWS with sin­gle-man­ning and high speeds, and that it was no longer ac­cept­able to run trains at full speed if the equip­ment was out of ac­tion. The rules here were also changed, such that if AWS be iso­lated, then a train may only run at high speed with a com­pe­tent per­son ac­com­pa­ny­ing the driver in the cab. This per­son must have full knowl­edge of the route and know how to stop the train.

By the time Uff’s re­port had been pub­lished, an­other fa­tal SPAD in­ci­dent had oc­curred - also on the Great West­ern Main Line, this time at Lad­broke Grove (see panel). This sec­ond ac­ci­dent led to a joint re­port into train pro­tec­tion sys­tems, headed by Uff and Lord Cullen, who was lead­ing the Lad­broke Grove in­quiry. Their re­port, pub­lished in Jan­uary 2001, said that both AWS and ATP “now rep­re­sent old tech­nol­ogy”.

It con­tin­ued: “As a re­sult of other sys­tems now be­ing de­vel­oped, there is no longer any se­ri­ous de­mand for gen­eral fit­ment of [ATP]”. One of those ‘other sys­tems’ was the Train Pro­tec­tion and Warn­ing Sys­tem (TPWS), which had been con­ceived as a de­vel­op­ment of AWS by a joint Bri­tish Rail/Rail­track work­ing group in 1994 af­ter it had been con­cluded that the na­tion­wide in­stal­la­tion of ATP was not rea­son­ably prac­ti­ca­ble.

TPWS was in­deed cheaper than ATP, but like ATP it also im­proved on AWS by au­to­mat­i­cally ap­ply­ing the brakes on a train that has passed a fit­ted sig­nal at ‘dan­ger’ or is ap­proach­ing one too fast.

Suc­cess­ful tri­als had been con­ducted be­tween 1997 and 1999, with wide-scale in­stal­la­tion be­gin­ning from the early part of 2000 and com­pleted around 2004. The joint in­quiry sup­ported the pro­gramme, but noted that its ben­e­fits were plainly lim­ited, as “de­spite the sub­stan­tial ex­pen­di­ture that it rep­re­sents, it will still per­mit a pro­por­tion of ATP-pre­ventable ac­ci­dents to oc­cur”.

Clearly, the in­quiry saw TPWS as an in­terim “bet­ter-than-noth­ing” so­lu­tion, pend­ing the in­tro­duc­tion of the Euro­pean Train Con­trol Sys­tem (ETCS), which pro­vides ATP func­tion­al­ity, and which they an­tic­i­pated be­ing rolled out from around 2008.

At the time, con­cerns over TPWS mainly re­lated to its per­ceived lack of ef­fec­tive­ness at speeds over 70mph. But although it would slow a train sig­nif­i­cantly, the sys­tem was later im­proved (‘TPWS+’) to in­cor­po­rate ad­di­tional over­speed sen­sors, thereby mak­ing it ef­fec­tive up to 100mph.

TPWS is now well-es­tab­lished and has played a recog­nis­ably large part in cut­ting the num­bers of SPADs from around 500 a year to fewer than 300 (the vast ma­jor­ity to­tally be­nign) on a rail­way that’s get­ting ever busier. Yet while SPADs are now rel­a­tively low in fre­quency, one oc­ca­sion­ally has the po­ten­tial for high-con­se­quence loss. With this in mind, and ahead of wider ETCS im­ple­men­ta­tion, an in­dus­try-wide steer­ing group con­tin­ues to con­sider whether TPWS in­stal­la­tion has re­duced the risk as far as pos­si­ble.

Else­where, the in­tro­duc­tion of LEDs has greatly en­hanced the con­spic­u­ous­ness of many sig­nals, while the po­ten­tial risk from over­runs is now con­sid­ered fol­low­ing in­ci­dents, be­fore ser­vice ad­just­ments and at the de­sign stage of new sig­nal­ing schemes.

In ad­di­tion to th­ese tech­ni­cal so­lu­tions, the in­dus­try has taken sig­nif­i­cant steps to­wards a bet­ter un­der­stand­ing of the hu­man be­hav­iours that can re­sult in a driver fail­ing to stop at a ‘red’. As re­cently as the Pur­ley SPAD of 1989, it was ap­par­ent that many thought the driver to be solely re­spon­si­ble, de­spite it later (in 2007) be­ing con­cluded that there was “some­thing about the in­fra­struc­ture of this par­tic­u­lar junc­tion [that] was caus­ing mis­takes to be made”.

RSSB (Rail Safety & Stan­dards Board) is cur­rently con­sid­er­ing the hu­man el­e­ment of the SPAD phe­nom­e­non more deeply, while its Board agreed the need to de­velop a strat­egy for the con­tin­ued risk man­age­ment of SPADs, in or­der to co-or­di­nate ef­fort to drive it down fur­ther.

On the point of pub­li­ca­tion, this strat­egy will pool in­dus­try knowl­edge and good prac­tice in SPAD man­age­ment, and con­sider fu­ture mit­i­ga­tion be­fore the wide­spread in­stal­la­tion of ECTS. It will also be pro­por­tion­ate to the risks SPADs present to the in­dus­try in re­la­tion to other train ac­ci­dent pre­cur­sors.

Man­ag­ing SPAD risk and mit­i­ga­tion has been one of the in­dus­try’s ma­jor suc­cess sto­ries since 2000. The in­dus­try means to make sure this con­tin­ues. Af­ter all, it only takes one SPAD to make a Southall… and no one wants that.

PRESS AS­SO­CI­A­TION.

Main pic­ture: The clear-up con­tin­ues on Septem­ber 20 1997, at the site of the Southall rail crash which left six pas­sen­gers dead and 147 in­jured. The life of a sev­enth pas­sen­ger would be claimed later in hos­pi­tal. Right: RAIL 315‘s front page shows the hor­rific dam­age.

PRESS AS­SO­CI­A­TION.

The driver of the stricken HST Larry Har­ri­son was ini­tially charged with man­slaugh­ter for fail­ing to ob­serve a red light, although th­ese charges were even­tu­ally dropped and his em­ployer GWT fined £1.5 mil­lion for breaches of health and safety.

A six-page crash in­ves­ti­ga­tion spe­cial in RAIL 315 cov­ered in de­tail the Southall crash.

The shat­tered re­mains of the cab of the power car, whose side was ripped off. The driver es­caped in­jury by re­treat­ing into the en­gine room be­fore the crash.

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