Causes of SPADs

[roythebus]

Carrying on from a comment that RugD (I think) made in the now locked WCRC thread, he mentioned that recently passed out graduate drivers "off the street" had a high incidence of SPADs and safety related incidents.

 

In my days on the railway SPADs happened fairly regularly usually without serious incident and were managed by arrangement with the local signalman and the driver. Anything serious which couldn't be dealt with locally was dealt with by the disciplinary method, usually suspension from duty for a few days. Re-training didn't usually come into the equation; the man was told "not to be a silly person" (using more colourful language) and not to do it again, which usually worked. But in those days the driver had had years of on the track experience as a fireman or secondman.

 

I still don't believe you can train someone with little or no railway experience to do the job off the street.

 

Having said that, the number of SPADs increased in the early 1980's with the introduction of modern stock with disc brakes which has been well documented everywhere. The BR Board even produced (unofficially) a leaflet about Percy Bedpan, a cartoon character on the Midland which showed a "moving block", taking a light hearted look at the brakes on the 318's or whatever they used out of St Pancras at the time. This was given to me by the late Alec Swain, I'll post a copy when I find it.

 

With the 508s on the Southern and the 455s later, there were some very worrying incidents which were made public, and other which were covered up, notably the "Shepperton Flyer" where the 455 ended up over Shepperton High Street, and another incident where a train failed to stop at Putney and eventually stopped at Mortlake. Most of these incidents were caused by the use of disc brakes and the WSP anti-slide systems. I personally had an incident where my 508 sailed through Hampton Court and ended up in the sand drag. Nobody was interested in that one as there was no damage done apart from my underwear!

 

As I've mentioned in other threads here and elsewhere, I mentioned these incidents to Major rose, the Inspecting Officer for Railways at the time who was giving a lecture on the role of his office at the Model Railway club in London. I was surprised to hear that his office didn't get involved in such things as new braking systems until there had been an incident, but did get involved in checking things like new signal interlocking 

installations.

 

The net result was that BR had to change the WSP systems to include a panic button which over-rides the WSP and isolated it, and to change the method of teaching driving techniques to be far more defensive. This then resulted in the techniques we see today, with trains creeping up to signals and stop marks 50m away from buffers! Is this really progress and has it made the railway safer?

[david.hill64]

I am pleased that this has been made a topic for discussion. When I worked for BR I was involved a lot with braking, adhesion and SPAD prevention/mitigation.

 

There is no doubt in my mind that the introduction of disc braked suburban stock, with the associated change to a 3 step Westcode brake controller, could have been handled better. The other change that is relevant is the bogie design: the bogies introduced at the same time rode much better at the wheel rail interface. The unwanted side effect of this is that there is less scrubbing action between wheel and rail so that contaminants are not cleaned away in quite the same way. Introducing all of these three things at the same time makes it impossible to judge what the over-riding factor was in regard to influence on SPAD rates.

 

SPADs were by no means confined to short disc braked trains: IIRC the longest recorded SPAD overrun happened with an 8 car VEP formation! (About 2 miles past the red, fortunately with nothing in the way).

 

I think it's also important to distinguish between those SPADS where the signaller has put back the signal to red giving the train insufficient braking distance, and those where for whatever reason the train has not stopped. BR classified these in a number of different ways. I am not sure if I can remember the exact definitions but I think they were as follows:

 

Misjudgement: this was the largest category that could simply (but erroneously) be considered as the driver not braking in time bearing in mind the conditions.

 

Misread: the driver read the wrong signal. (There was a classic case of this in Gloucester in the early 1970's with a pair of class 20's. Unusual visitors at that time. A pair appeared on a freight from the north and were banished immediately going via the slow lines towards Engine Shed Junction (?). The driver saw the green and accelerated through the buffer stops at the trap at the end of the loop. The green was for a passenger train on the main line!

 

Disregard: the driver ignored the signal. I think Ding Ding and Away SPADs were in this category.

 

Miscommunication: when the communication between driver and person providing a movement authority has been misrepresented.

 

Technical: a brake fault had developed.

 

I think roythebus's comments about local management are correct and the true number of SPADs was hidden from view. I asked a friend of mine - who was one of the last BR SR drivers if he had had any SPADS. Yes he said, all unreported, 'The cause?' I enquired. 'Youthful exuberance' the answer.

 

I am interested to see how this discussion continues!

[The Stationmaster]

Regrettably I'm afraid the term 'defensive driving' has been much abused by the way it is applied in Britain.  SNCF have practiced for years and it is often (probably rightly) advanced) as one of the reasons they have a very low SPAD rate and it is an education to ride with an SNCF Driver and see what 'defensive driving' means to him - it's simple; adverse signal and the brake goes in.  They still pull right up to the blocks at a terminus, they still actually stop just in rear of a red signal rather than half a street in rear and so and there is  no proscription about 'X mph at the AWS magnet' and so on.  In reality it is what I prefer to call 'professional driving' but is defensive and not proscriptive.

 

Now compare that with Britain where the distance between, say, a double yellow and the red is variable - and not just in relation to gradients or line speeds - whereas in France and even more so Germany that distance (or its equivalent) is as near consistent as makes no difference on main line routes.  Look at the UIC fiche on line capacity - it would (and I have seen it happen) give a British signal engineer kittens quite a shock just reading it while the average money oriented person in DafT or politicos would die of fright at its implications because it explains why mainland European railways have multi-tracking while here a double line is considered adequate.  Look at a double/multiple line timetable graph in almost any mainland European country and it is regarded as little short of criminal not to have trains running with at least a couple of greens in advance of them on =mas signalled routes.

 

Now compare that with some of the routes you used to work over and how you managed, or rather had to manage, running on double yellows in order to keep time (or as near to it as you could).  The not very nice fact is that some parts of the British network set-up SPADs before a train gets anywhere near them  but the odd fact nowadays, compared with the past, is that the number of SPADs that leads to seems to have reduced.  What has unfortunately come up the rankings of causes in recent years are mobile 'phones  and inexperience/what amounts to not as good as it should be road knowledge (also perhaps coupled with inattention?).

 

Unfortunately - in some respects - what many of us older folk call 'boil-in-the-bag' Drivers are with us to stay.  The agreed intention prior to the Ladbroke Grove collision was that from starting off the street to out driving (but still involving some road learning depending on depot etc) would be six months, you could be a butcher dressing turkeys for the Christmas market and still be out as a Driver in time to work summer specials to the seaside assuming you passed everything ok.  Ladbroke Grove raised some issues and led to changes and I think the period was then increased to 9 months plus road learning, I don't know what it is now, but in my mind more than anything else it showed up inadequacies in route knowledge as a bloke passed a double yellow which you could see from a quarter of a mile, a single yellow you could almost see from the double yellow then an entire gantry of reds (when he should very clearly have been looking out for one ready to stop) followed by the fact that he was so obviously (to anyone who can count) on a line he shouldn't have been on once he passed a particular crossover - that was down to training, or rather shortcomings in training and not much else.  If he had been driving defensively - in the French style - he would have stopped at the red because he knew where it would be and only as he came to a stand would he be looking to see if the signal had stepped-up to a proceed aspect.

 

So lots of things to put right in 'the system' but at the same time the 'human error factors' will still need to be addressed and repeatedly hammered home.

[55F]

Surely the only effective way of preventing SPADs is to create a safety culture where ALL SPADs are reported regardless of the severity or triviality of the cause.  Only when that data is collected and analysed can the root causes be identified and addressed.  The causes may lie in the equipment, the procedures, the training, human factors or indeed a combination of these causes.  The inherent safety culture of the entire operation is of paramount importance.  The sound reporting culture should ensure that precise causes are established and appropriate preventative action put in place.  Life is too short to learn from merely our own mistakes; we must capture the mistakes of others and learn from them as well.

 

Of course in most industries the old procedure of a discreet kick up the backside or even worse a cover up to avoid punishment didn't work.  We carried on doing the same old thing and surprise surprise, getting the same results.  This is why safety culture is of overriding importance; fearless reporting of incidents, including self reporting is vital.

 

Aviation, in which I spent my career, has made giant strides towards safety over many years by applying these principles.

 

55F

[darrel]

A SPAD can happen to anyone a newly qualified driver can make an error due to inexperience, an old hand can make a mistake due to complacency "that signal always comes off!"

A lot of them are caused by distraction, that could be a fault on the train the driver is focused on the fault and not the signal ahead, passengers at a station asking questions for example the signal showing yellow and the driver having been distracted starts away and powers up normally forgetting the signal aspect and then seeing the red when it's too late.

Fatigue may also be an issue in British Rail days you did an 8 hour shift with a 1 hour break today it is in a lot of cases a ten hour shift with a 40 minutes break.

Repetitive work, in BR days there was more variety of work one day working freight next a local passenger train working more routes some places you are working the same route every day with the same traction. It leads to over familiarity that signal always goes from yellow to green as you enter the station, one day it doesn't.

Pressure to run on time getting letters asking you why you lost two minutes here and there. (They go in the bin) but someone else may feel the pressure.

Poor sighting of signals or signals in a stupid location. I know of one which was positioned a long distance from a station and just after a bridge meaning it could not be seen until you were very close to it. Putting it before the bridge would have been better. Having intermediate platforms where you get a signal before the station and the next one beyond the platform out of sight. Any distraction at the platform could cause you to forget about the red ahead. DRA is vital in these cases.

Then there is read across where there are two or more signals for adjacent lines and you pick out the wrong signal. Read through where you see two or more signals in front of you on straight track and you see one clear and you think it's yours. I know one location like this where because of overhead wires you see the signal furthest from you before you see the one before it.

External light pollution. One location we have you get the yellow signal go round the corner and you see a green then another green and another green then you see your signal at red. The greens are all traffic lights on a nearby road.

My way of doing it and it depends obviously on location and line speed. If you get two yellows shut off and start bringing the speed down, one yellow speed right down to 25 and crawl. 15mph at the tpws magnet and stop when you can read the signal number. If you are running under restrictive aspects following another train reduce speed and give the other train time to get out of your way. I can think of two locations where I will crawl up to a yellow to allow it to change to two yellows as the red signal is poorly sighted.

You won't spad if you don't have a red signal to SPAD.

As has been said in the old days a lot of SPADs went unreported not today even 1 foot beyond the signal and you are in the mire. Data recorders, all phone calls reported CCTV at the front of many trains, not to mention the passengers on the train all too willing to grass you up on Twitter and Facebook. You have no chance of getting away with it. If you didn't report it and got found out it would be the end of your driving career.

[Edwin_m]

One technical innovation not mentioned yet is that nearly all multiple units are now fitted with sanders, which come in automatically when brake applications are made and poor adhesion detected. 

[PaulRhB]

Surely the only effective way of preventing SPADs is to create a safety culture where ALL SPADs are reported regardless of the severity or triviality of the cause.  Aviation, in which I spent my career, has made giant strides towards safety over many years by applying these principles.

They all are already for exactly those reasons. As any safety related incident ultimately has consequences, Drivers accrue points for incidents if severe or several in a short period, then there will always be fear if they have other points already. Knowing your job is at stake is one of the reasons you follow rules, it's human nature to not admit being wrong much of the time. One thing to remember is that the data logger can exonerate as easily as prove liability.

[roythebus]

One very-near SPAD I had was at Surbiton on the down local with a 4SUB, usually the most sure-footed of units with straight Westinghouse brake. Middle of the day, sunny day, some p'way workers about, I ran into the platform, applied the brake, train started to slow, then picked up and slid to the red. Cause, the p'way had been oiling the fishplates in the platform road and there was oil all over the rail head!!

 

Maybe the Westcode should have been a 5 step brake rather than the 3-position one fitted. In the early days of the we didn't have sanders on anything except locos.

 

As for running at reduced speed on double yellows, the SW had double-double yellows from Waterloo to Woking due to short block sections and we would regularly run from Waterloo to Woking in the evening peak on double yellows, watching the train in front's tall light in the distance. Run at reduced speed and you reduced line capacity. We were timed at up to 90 from Surbiton to Woking, all on double yellows. 

[The Pilotman]

As has been said in the old days a lot of SPADs went unreported

I don't know if the 1990s qualifies as "the old days" but that was when I was involved in signalling. At the start of that period, I do recall some SPAD incidents being dealt with at a (very) local level and nothing else came of it. Having said that, I know of one case where a SPAD was "managed" at a local level but the incident played on the mind of the driver involved so much that he decided to report himself the following day. Obviously that caused all sorts of issues... That incident, and our boss making it quite clear that any unreported SPAD would result in suspension and likely dismissal, rather put an end to the practice.

[roythebus]

SPADs involving a signal going back in front of the driver are more worrying for the driver as it may have gone back for a reason; has something fallen off in front of me, where's Tangmere? 

 

One of those I had going down the local through Weybridge on a fast Pompey one Sunday at 90mph; the Weybridge home signal went back at me at 90; it was green, went to red. I stopped past the platform starter, phoned the box, he was very apologetic as he'd pressed the wrong button. I called him a rude name that rhymed with front, no harm done, we had a laugh and carried on.  I might have needed a similar favour from him some time! All before the days of on-train recorders.

 

But then, with engineering work on the down fast, it could have been an on-track machine that had become an off-track machine.

[Fat Controller]

SPADs caused by sudden reversion of a signal to danger might also be due to a track-circuit failure in front of the train, mightn't they? This is certainly the case on TVM-equipped routes, the only sort that I have personal knowledge of.

Regarding Mike's comments about 'boil-in-the-bag' drivers, I recollect one study showing that the groups most likely to suffer Category A (Driver Error) SPADs were either those who had only recently passed out, or those who had about eight years under their belt, presumably because, as the old adage goes 'familiarity breeds contempt'. The industry has worked very hard to reduce the incidence of SPADs, it being one area where an industry-wide group was set up, and seems to have been very effective.

[The Stationmaster]

 

 

As for running at reduced speed on double yellows, the SW had double-double yellows from Waterloo to Woking due to short block sections and we would regularly run from Waterloo to Woking in the evening peak on double yellows, watching the train in front's tall light in the distance. Run at reduced speed and you reduced line capacity. We were timed at up to 90 from Surbiton to Woking, all on double yellows. 

Exactly the problem I referred to Roy - but in your case a practical example of it.  Now apply the French dictum and that is 'put the brake in at a double yellow' - in the British situation you'd get a trail of delays snowballing behind him, in the French situation you don't.

 

There was a situation back in the '90s where two Eurostars in the evening went 'the country route' to avoid congestion via Tonbridge - one for Bruxelles with an SNCB Driver and the other for paris with an SNCF Driver but oddly despite being clear run timetabled the trans always suffered delays.  It turned out that the SNCF Driver was reading through the green to the next signal in advance which was showing yellow and his training told him to put the brake in when he saw a yellow - even if the signal immediately in advance of him was showing green.  He definitely wouldn't have managed at all well on various other parts of the Southern or even on the GWML during the morning peaks where running at 90+mph on double yellows was the only way to get a right time arrival at Paddington.

[Richard E]

Interestingly a former colleague of mine turned to driving trains when he was made redundant in about 2005. It was quite interesting to find that it took a year from induction to his being let loose on his own. About a year and a half later another former colleague joined him and the time from induction to driving unaccompanied was about the same then.

 

Of course none of this speaks to current conditions.

[Rugd1022]

On average it takes about ten to twelve months to train a driver from scratch, a major factor in this is the availability or otherwise of mentor drivers to accompany them. There are of course cases where it has taken less time but even so it is a long drawn out process. Once passed out on traction and rules the new recruit then has to start learning his or her core routes before becoming anything near productive.

 

Some TOCs are averse to training graduates and poach drivers from other companies where possible, and the actual number of 'handling hours' varies from one company to another. These hours are for 'wheels turning' and not 'time in the seat', plus there has to be a fixed amount of night time driving involved. On the freight side the handling hours are generally higher in number and they have to include a certain amout of light engine working.

 

Regarding SPADs and defensive / professional driving, the maximum speed allowed over an AWS magnet on approaching a red varies from one company to the next, at FLHH it's 10mph, with some passenger companies it's 25mph, slightly over and you'll find yourself on the carpet with some explaining to do. This single factor is often the cause of severe delays to following trains and surprisingly some signalmen are unaware of the different speeds each company has decided on. Approaching a red with a heavy freight (uphill or down) and recovering from a standstill at that signal all takes time and has to be judged according to route knowledge and road conditions.

[CovDriver]

As some people on RMweb know I'm currently in the training process of training to become a driver and as for causes of SPADs is constantly drummed into use especially for some others on our course who are off the street so to speak.

The speed for us as we go over an AWS magnet on the approach to a Red signal is between 15-20mph.

The course itself lasts 9 months covering the various stages of training I'm hoping to start my mainline handling mid January 2016 where I'll have to complete 230 hours driving with 40 of those in darkness then hopefully if I pass out as a post qualified driver I'll have 12 months of assessments including OTDR downloads and rides with my Driver Manager plus time in the class 350 Simulator to carry out tasks of single line working, Temporary block working and Wrong direction moves.

In total it will have taken almost three and a half years to become a train driver from the day I handed my application form in.

 

Cheers

 

Colin

(Formerly known as Cov Guard)

[darrel]

Good luck COV guard listen to your DI he has been there and done that listen to your DTM remember he wants you to pass out, he does not want to fail you. If you ever need any advice PM me I don't work for your TOC but if I can help I will. Same goes out to all trainees out there whoever you work for.

[roythebus]

Another SPAD I had was with a 455, leaving Waterloo, approaching Vauxhall, doing about 15 mph approaching a red, put the brake in step 3 before the AWS magnet, sailed 3 cars past the red. It just did not want to stop for me. Squared up with the bobby who said you're not the first today!

[david.hill64]

As Edwin pointed out, a useful technical innovation now are the auto sanders used during WSP activity.

 

Wheel Slide Protection systems are not just about saving money by reducing wheelflats and the need for consequent wheel turning. A sliding wheel has less friction than a rotating (but braked) wheel. One of the earliest SPAD reports I read - unfortunately don't have access to it any more - quoted a GWR driver reporting to Mr Gooch that his wheels 'picked up' as he approached the signal and his braking was reduced.

 

BR ran many trials with the Tribometer train until the demise of BR Research (BRR). It was found that optimum adhesion (and hence braking rate) was found when the wheel continued to rotate but at a speed less than the synchronous speed: in other words when the wheel was slipping. The effect of this was two fold. Firstly the slipping action conditioned the wheel surface, leading to an improvement of adhesion available for that wheel. Secondly the slipping action also conditions the rail surface, leading to an improvement in adhesion for subsequent wheelsets.

 

BRR used this information to develop a WSP testing rig. A WSP rack would be fed speed inputs from computer records of actual low adhesion conditions and would drive a pneumatic system typical of the brake system on a modern vehicle. By this method the algorithm in the WSP system could be enhanced. Unlike the original simplistic WSP systems fitted to the first disc braked stock, which simply dumped all of the brake cylinder pressure until the wheel had reached synchronous speed again (during which time there was obviously no braking force by the affected wheelset(s)), modern WSP systems include a holding valve which permits a variable brake pressure in each cylinder up to the full demanded pressure. This has the effect of putting the wheelsets into controlled slip, thereby making best use of the adhesion available.

 

These conditioning effects have been known for a long time. Japanese Shinkansen trains have a lower braking rate on the end cars, compensated by a higher braking rate on the cars at the very centre of the train. I was BR's representative on the European Research Committee's (ORE) high speed adhesion working group. This group was investigating the conditioning effects and how they could be used to develop new WSP systems. Unfortunately the chairman was French and refused to believe that BR could have any technology that was superior to French UIC technology and they spent a lot of money helping Faiveley develop their AEX WSP system. Comments that it was not fair to use funds from nationalised industries across Europe to help a French company develop a superior system were beyond the chairman's ability to comprehend, so BR withdrew support. The WSP test rig was subsequently used by many suppliers of WSP systems to optimise their WSP systems to the characteristics of real vehicles and adhesion. The standard WSP test had been to coat rails in detergent and do a practical test. This was fine except that detergent isn't a common contaminant and behaves in a different way to natural contaminants. Leaves are of course the classic example, as is fishplate oil as described above. The other killer is light moisture on a slightly rusty rail head.

 

The combination of a good WSP system and the sanders will have reduced the number of SPADS considerably, but even so ultra low adhesion caused by leaf debris cannot be controlled by WSP alone, hence the need for sandite and other rail treatment systems.

[david.hill64]

Another SPAD I had was with a 455, leaving Waterloo, approaching Vauxhall, doing about 15 mph approaching a red, put the brake in step 3 before the AWS magnet, sailed 3 cars past the red. It just did not want to stop for me. Squared up with the bobby who said you're not the first today!

Reminds me that BRR had also developed a Low Adhesion Warning System: excessive WSP activity in a train would be mapped and could then be relayed as a warning to following trains. Sounds like Roy could have used that!

[david.hill64]

It is going to be very interesting to see what happens to the SPAD rate when ETCS level 2 is brought in. At first glance you would expect that SPADs with a full ATP system will be impossible, but all ATP systems have an inbuilt 'guaranteed minimum brake rate' that is used to determine the emergency intervention speed. The problem is that this guaranteed minimum brake rate isn't guaranteed, it's just highly likely to be achieved. If wheel rail adhesion conditions are atrocious the train will not be able to stop. There is a trade-off between setting the guaranteed rate too high - in which case it isn't guaranteed to be guaranteed - and setting it too low, in which case line capacity is destroyed.Seeing that various bodies are peddling the myth that ETCS will increase track capacity, I wonder what guaranteed rate will be used.

 

Has there ever been a SPAD on an ATP fitted Chiltern or GW train? Does anybody know?

 

As others have pointed out eloquently above, UK has a very intensively used network compared with continental practice. Running more trains more closely increases the possibility of disruptions and hence red signals. You cannot have a SPAD if you never see a red!

[Gwiwer]

I read this topic with interest not least as an informed railway staff member but never in the driving grades.

 

The stories and opinions of experienced professionals are invaluable and lessons could and should be learned.  SPADs don't just happen - they are caused.

 

Each and every one should be reported though perhaps not every single one should require the driver to be relieved at the incident, tested, rested etc etc.  Some we know are "technical SPADs" and are caused by a signal reverting to stop in front of a moving train which might be due to a fault, signaller intervention in emergency (six bells or its current equivalent) or signaller error.  The poor driver watches the road taken amor him or her and is quite unable to stop.

 

My local network around Melbourne is equipped with something akin to the LU system with train-stops / trips at all signals whether automatic or manual.  Tread-braked trains generally don't SPAD; there have been issues with the disc-braked Siemens trains SPADding which have been ameliorated (but not eliminated according to some drivers) by recoding the computer to give the driver more control.  We had a signal fault on my line only two days ago whereby an auto-signal persistently reverted to reds (it takes two reds to stop our trains!) with a train at full speed 50 metres shy of it.  Six consecutive trains were abruptly halted by the trip though with the driver having braked first in every case.

 

The UK network is extremely intensively used in the main and has protection accordingly but there is no 100% foolproof system.  Back in the 1980s a colleague was driving a class 315 train (Westcode-fitted) from Gidea Park to Liverpool Street; as many of us know the approach to the suburban platforms is down Bethnal Green bank with a sharp curve at the bottom and just the length of the 8-car train from the end of the curve to solid bricks and mortar.  Let's just say he required a change of underwear and a couple of days stress leave after accelerating down the bank desperately trying to get any sort of brake.  The train stopped 5cms from disaster.

 

I was aboard one of our Melbourne Siemens trains one evening which failed to slow as I would have expected approaching a scheduled stop; the platform starter would have been held at reds until the train was almost at a stand due to there being a level crossing right off the platform end.  The train duly ran through the station, over the crossing (with its booms lowered) and came to a stop with four cars, of six, off the platform and the trip having failed to act.  I never discovered the outcome of that but it was treated at the time as a SPAD and the train taken out of service.  

[96701]

Another reason for SPADS is power failure or 'blips'. A sudden spike or drop in voltage can cause all the routes to drop out and cause many SPADS, hence the installation of many UPS at supply points. The UPS provides a constant voltage whatever the incoming supply is doing.

[Edwin_m]

The WSP test rig was subsequently used by many suppliers of WSP systems to optimise their WSP systems to the characteristics of real vehicles and adhesion. The standard WSP test had been to coat rails in detergent and do a practical test.

Still in use apparently.  I read recently that DeltaRail (the remains of BR Research) had sold it to ESG, the engineering division of DB in the UK, who are probably better placed to keep it going. 

[david.hill64]

Still in use apparently.  I read recently that DeltaRail (the remains of BR Research) had sold it to ESG, the engineering division of DB in the UK, who are probably better placed to keep it going. 

Yes I read that too! It has lasted well.

 

I remember we called it Rosser's Organ after its developer, though it wasn't particularly tuneful!

[Glorious NSE]

Has there ever been a SPAD on an ATP fitted Chiltern or GW train

 

Absolutely. Two high profile ones that come to mind are Southall where the ATP was fitted, but not operational, and Ladbroke Grove, where I believe the HST's clear signal will have gone back to red as the Turbo occupied the track circuit...neither one was effectively preventable by ATP (though the first one would have been if it had been working!)

 

Not sure I've heard of one on due to low adhesion, but it's entirely possible as per your description, none of these systems are effective if you have no grip. Google "RAIB Esher 2005" for a modern example, sans ATP but I can't see how that system would have made the slightest difference...