Croydon Tram Accident

[Colin_McLeod]

I see the BBC are already starting scaremongering about the safety of trams. At least on this occasion their resident 'expert' on all things rail is trying to put things in perspective.

 

http://www.bbc.co.uk/news/uk-37941085

  

Which part of that BBC article is scaremongering?

BUMP.

 

I would appreciate a reply Phil

[phil-b259]

  

BUMP.

 

I would appreciate a reply Phil

 

I think the article has been edited (possibly several times) since it first appeared and upon re reading it, it seems less sensational than I recall.

 

My recollection was that the tone was a "look how dangerous trams are - they don't have anything to stop speeding, someone must do something immediately" sort of approach usually found in certain Newspapers - but which is not present in the article now.

 

More generally I feel that due to the growth of the internet and social medal / mobile devices, the quality of BBC articles (particularly those written as events are still unfolding) has taken a definite turn for the worse in recent decades as they feel the need to compete with others.

[jamie92208]

Mention was made some posts back about the mechanism of injury when vehicles turn on their sides.   Several years ago a coach carrying many of my work colleagues overturned on a roundabout after failing to slow down.   5 of the passengers were killed.   In all cases the glass had shattered and they fell onto the roadway and in effect were run over by the side of the bus as it came to a stop.   This is quite a common method of injury .  I have no idea if this has happened at Croydon and no doubt we will all find out in due course.  However this type of injury in road coach accidents is more common here than in the US where there is much more metal in the coach sides. This is probably due to different construction regulations. 

 

On a slightly lighter note there was a set of runaways in Keighley on their trolleybus system.  This was the Cedes Stohl system which had a 4 wheeled trolley running on top of the wires with a large pendulum weight uder it to keep it on the track and a flexible lead running down to the trolleybus.   At least three times the conductor let go of the lead when turning round at Oakworth terminus.  The Trolley then set off on it's down the hill into Keighley town centre.  It always got to the main square safely then derailed into the same shop window every time. when I failed to negotiate a sharp bend.  Apparently they used to telephone ahead to warn the shop.  The trolley and weight weighed a couple of cwt. 

 

Jamie

[Gwiwer]

Out of curiousity, was there a check-rail on this curve?  I can think of other cases, where the curve radius is much greater, yet a check rail is fitted.

 

 

There is no check-rail on this curve.  Tram tracks are often devoid of check rails even on the sharpest curves because of the low speed at which the vehicles (should) operate.  A check-rail should not be confused with the inner face of grooved tramway rail which can be seen inside the running rail, usually on street sections, and which serves as much as anything to define the groove in which the wheel runs and prevent overspill of road surface (bitumen or concrete) into the flangeway.

 

Trams are required to pass rail crashworthiness tests similar to main line rolling stock.  Some designs have sacrificial panels and inner structures designed to absorb impact.  2551 has remained apparently intact on the upper side and with little if any damage to the underside so far as can be seen thus far.  It will be a different story when the lower side is revealed though I would expect the basic structure to have remained more or less sound.  If as we believe might be the case the incident was caused (or contributed to) by a major overspeed then my understanding of tramway design and dynamics is that the leading truck would have entered the curve, derailed when centrifugal force exceeded other forces and the whole thing has flipped sideways like a "merry mixer" ride at a fairground.  That it remained more or less in a straight line shows the strength and integrity of the flexible centre turntable join.

Edited November 12, 2016 by Gwiwer

[Derekstuart]

Hello Jamie

 

Have you any data about the comparative accidents between GB and US? Having worked in road transport- including a short period in accident investigation- I am interested to learn of US approach to this. I am aware only of three coaches ending on their sides- one at Heathrow with a driver taking a bend far too fast, one who was drunk and thought Newport Pagnell services with its very slow entrance was in fact the slip at J14 and I can't recall what caused the other one. Two of them caused the type of injuries you describe, the third one didn't.

 

I am not in the sort of job involving that now, so a bit out of touch- but even then I would struggle to associate the word "common" with this level of injury so it would be interesting if you could share any info you have on US safety (by pm or in a new thread to avoid o/t if you prefer)

Mention was made some posts back about the mechanism of injury when vehicles turn on their sides.   Several years ago a coach carrying many of my work colleagues overturned on a roundabout after failing to slow down.   5 of the passengers were killed.   In all cases the glass had shattered and they fell onto the roadway and in effect were run over by the side of the bus as it came to a stop.   This is quite a common method of injury .  I have no idea if this has happened at Croydon and no doubt we will all find out in due course.  However this type of injury in road coach accidents is more common here than in the US where there is much more metal in the coach sides. This is probably due to different construction regulations. 

 

Jamie

[wombatofludham]

Trams have different wheel profiles in the UK to main line stock.  The flange is also used in slow speed street pointwork to support the weight of the vehicle (a flange bearing frog) to reduce the noise impact of the wheel tread impacting the gaps in the frog causing vibration and noise in neighbouring properties.  Flange riding in pointwork has been around for many years in tramways. The flange also assumes a greater role in steering the vehicles particularly on street than main-line vehicles which rely more on the conicity of the wheel tyre.

 

The different wheel profile between street running trams and heavy rail vehicles is one of the issues that the tram-train trials in South Yorkshire was supposed to be sorting out.

 

There's an interesting research document on the wheel-rail interface issues on British light rail systems at http://orr.gov.uk/__data/assets/pdf_file/0004/4387/sres-RTU-rep_90_3A_iss1.pdf

[wombatofludham]

Some of the technical issues related to tram-train operation, including the different wheel standards, is illustrated in this Network Rail presentation

 

http://www.applrguk.co.uk/media/files/lr%20uk%20tramtrain%20network%20rail%20tecnical.pdf

[Chameleon]

I'm quite surprised that they don't have some sort of TPWS system in place. Even a cut down version with over speed aerials on the track. With corners that severe and the potential of running round them far too fast, an automatic system of some sorts should be essential. Suppose it would be too expensive as usual.

[jamie92208]

Hello Jamie

 

Have you any data about the comparative accidents between GB and US? Having worked in road transport- including a short period in accident investigation- I am interested to learn of US approach to this. I am aware only of three coaches ending on their sides- one at Heathrow with a driver taking a bend far too fast, one who was drunk and thought Newport Pagnell services with its very slow entrance was in fact the slip at J14 and I can't recall what caused the other one. Two of them caused the type of injuries you describe, the third one didn't.

 

I am not in the sort of job involving that now, so a bit out of touch- but even then I would struggle to associate the word "common" with this level of injury so it would be interesting if you could share any info you have on US safety (by pm or in a new thread to avoid o/t if you prefer)

 

Hi Derek, unfortunately I don't have any data.   The Wakefield coach crash, where I knew many of the passengers, obviously is one I know about.   Perhaps the word common was the wrong one.   I remember at the time there was a lot of talk about how the glass formed a portion of the strength and obviously that disappeared once the glass broke. I have vague memories of another overturning incident with a tour bus in Scotland but can't give any details.  From personal observation US greyhound buses have smaller windows and are basically a big strong steel frame with large pillars that have windows fitted in rather like railway coaches.  There was much talk at the time of the Wakefield crash about how our standards should be the same as the US ones.   However I do not have any comparative data.   I have also see the same mechanism of injury in one or two car crashes though these decreased one seatbelts became compulsory. 

 

Jamie

[roythebus]

UK road coaches do rely on some degree for the window glass for their overall strength. But all are built with roll-over resistance. US coaches I would suspect are far heavier than their UK and EU counterparts due to the larger amount of steel in them.

 

There's been a few instances of double deck buses that have turned over on roundabouts, with 2 in the same area in a short space of time in the Watford area. Both were caused by driver error or deliberate driver action, both involving full loads of school children. Luckily there were no fatalities but lots of superficial injuries. Both drivers received custodial sentences for their deliberate actions. With double deckers there is the 37% roll-over factor built in, and additionally there is a huge cushion or air to displace as they topple sideways.

 

London Transport used to have an RT double decker which they used to demonstrate how to upright overturned deckers. It was interesting to see how slowly the bus was turned over and how slowly if fell. No windows were broken either. 

[jjb1970]

I'd be surprised if this tragedy was indicative of an underlying systemic technical weakness of tram safety but I am sure the investigation will establish what happened. I think the reaction for the most part has been measured with little sign of kneejerk reactions. Clearly something went wrong, the investigation will establish what that was and if necessary improvement measures will be proposed.

On Wolmas, as much as I find him a typically annoying rent-a-gob pundit, in this case I think comments have been perfectly reasonable.

[dhjgreen]

This report includes a suggestion that there was a near miss a few days before the incident:

 

http://www.bbc.co.uk/news/uk-england-london-37960541

[Gwiwer]

This report includes a suggestion that there was a near miss a few days before the incident:

 

http://www.bbc.co.uk/news/uk-england-london-37960541

 

That has surfaced before.  It might or might not be the same alleged incident as one or two others have suggested via social media took place.  And it might or might not have involved the same driver.  That it is being taken seriously is only right and proper and also shows us all that if we are to post something into the public domain we don't know where it might end up so make it factual, offer it clearly as an opinion or be ready to face any consequences.

[ejstubbs]

Would data from 31st October still be available on the onboard log of which tram was involved?  Given that the Facebook post is timed at 05:26 and services on that route start I think around 45 minutes earlier, presumably that would narrow down the search for the tram which might have been involved.

[ejstubbs]

Wolmar was simply a broadsheet journo and bandwagon railway-basher in the past

Christian Wolmar is the Labour candidate in the Richmond Park by-election (1st December)

 

So a journalist/media 'pundit' with political ambitions and slightly odd hair.  Remind you of anyone else? 

 

I would, however, agree with those who've pointed out that on this occasion his reported comments were measured and sensible.

Edited November 12, 2016 by ejstubbs

[ruggedpeak]

As someone with some knowledge of investigating serious road collisions and the legal processes, there have been various bits of nonsense and some accurate comments on the situation.

 

Arresting a suspect in England falls under the Police & Criminal Evidence Act (PACE) in many but not all cases. There is a large amount of guidance and procedure called "Codes" that go with them https://www.gov.uk/guidance/police-and-criminal-evidence-act-1984-pace-codes-of-practice Code G covers arrest. Worth reading the early part of this document to understand why a driver would be arrested at the scene of a multiple fatality. Whilst the Police are investigating in respect of offences, where there are or may become fatalities (i.e. seriously injured persons who may die later as a result of injuries from the incident) the Police investigation will also inform any Coroner's Inquest.

 

Government policy is that any road collision involving serious (life changing or life threatening) injuries or fatalities is treated as a crime and properly investigated. By definition this will involve the use of Police powers under PACE, Road Traffic Act etc. Officers have the power of arrest where there is suspicion of an offence. This is a key role of initial investigators at the scene, to establish an initial view of the causes of the incident and act accordingly.

 

If for example the scene showed signs of the track being tampered with (e.g. rails removed) then clearly they will take a different approach to a scene where the train and track appear fully functional. If there are persons at the scene involved who the Police reasonably suspect may have committed offences relating to or causing the fatal incident, then they are likely to arrest on suspicision of relevant offences. At the point of arrest this gives investigators powers to investigate in more depth and get access to information that otherwise might not be available as well as basic identification verification (fingerprints, DNA possibly). Some evidence can only be collected at the scene, after which it is too late. With mutliple fatalities it is clear the families and public will want a thorough investigation and any offences dealt with, and the Police will want to ensure they maximise the opportunities to collect evidence.

 

Whilst there is often a simple explanation for what happened, equally investigations turn up other evidence that shows it was not as clear cut as it first appeared. Just because the driver has not been arrested does not mean they will be charged with anything. Someone stated charge has to follow arrest. This is entirely wrong.

 

My personal view of this tragic incident is that it will be a complex investigation and the outcome will not be straightforward. My thoughts are with the families of those who died and the driver who, whatever the facts of this incident, is going to have a very tough time.

[ruggedpeak]

Hi Derek, unfortunately I don't have any data.   The Wakefield coach crash, where I knew many of the passengers, obviously is one I know about.   Perhaps the word common was the wrong one.   I remember at the time there was a lot of talk about how the glass formed a portion of the strength and obviously that disappeared once the glass broke. I have vague memories of another overturning incident with a tour bus in Scotland but can't give any details.  From personal observation US greyhound buses have smaller windows and are basically a big strong steel frame with large pillars that have windows fitted in rather like railway coaches.  There was much talk at the time of the Wakefield crash about how our standards should be the same as the US ones.   However I do not have any comparative data.   I have also see the same mechanism of injury in one or two car crashes though these decreased one seatbelts became compulsory. 

 

Jamie

Few observations. I travelled to school by coach in the late 80's and used to chat to the drivers. I recall discussing Plaxtons coach bodies as we were in one. The driver advised that certain coach chassis (made by the likes of Volvo etc) that Plaxtons put their bodies on were shorter than others. I forget which, but some only had solid chassis frames between the axles, meaning the front and rear of the coach was just bodywork. This led to cracks and the fact that the driver had no crash protection as he was sitting in a bit of bodywork unsupported by a chassis frame. The body was just sheet metal and glass on the chassis, with only the chassis providing structural strength. Hopefully coach design has improved since then but I don't think road coaches are designed to withstand overturning to any great degree.

 

The RSSB has done a lot of work around railway coach safety and seatbelts, windows etc. http://www.railwaygazette.com/news/single-view/view/study-says-no-to-seat-belts-on-trains.html This states no seatbelts but laminated glass as heavy rail accidents have shown that people survive if they are thrown about in the cabin as long as they don't get thrown out the windows, and seatbelts aren't suited to the nature of rail incidents as against vehicular ones, causing more injuries. How this may relate to trams/light rail I can't say. This work was informed by a significant number of heavy rail incidents.

[PatB]

Few observations. I travelled to school by coach in the late 80's and used to chat to the drivers. I recall discussing Plaxtons coach bodies as we were in one. The driver advised that certain coach chassis (made by the likes of Volvo etc) that Plaxtons put their bodies on were shorter than others. I forget which, but some only had solid chassis frames between the axles, meaning the front and rear of the coach was just bodywork. This led to cracks and the fact that the driver had no crash protection as he was sitting in a bit of bodywork unsupported by a chassis frame. The body was just sheet metal and glass on the chassis, with only the chassis providing structural strength. Hopefully coach design has improved since then but I don't think road coaches are designed to withstand overturning to any great degree.

 

The RSSB has done a lot of work around railway coach safety and seatbelts, windows etc. http://www.railwaygazette.com/news/single-view/view/study-says-no-to-seat-belts-on-trains.html This states no seatbelts but laminated glass as heavy rail accidents have shown that people survive if they are thrown about in the cabin as long as they don't get thrown out the windows, and seatbelts aren't suited to the nature of rail incidents as against vehicular ones, causing more injuries. How this may relate to trams/light rail I can't say. This work was informed by a significant number of heavy rail incidents.

 

I'm not sure of the situation in the UK but I've always assumed it to be the same as here in Australia where coach and bus bodies have to meet quite stringent requirements for rollover protection. As usual, the requirements here came about as a result of a number of rather messy coach crashes involving overturning.

[Gwiwer]

The driver advised that certain coach chassis (made by the likes of Volvo etc) that Plaxtons put their bodies on were shorter than others. I forget which, but some only had solid chassis frames between the axles, meaning the front and rear of the coach was just bodywork. 

 

The RSSB has done a lot of work around railway coach safety and seatbelts, windows etc. http://www.railwaygazette.com/news/single-view/view/study-says-no-to-seat-belts-on-trains.html This states no seatbelts but laminated glass as heavy rail accidents have shown that people survive if they are thrown about in the cabin as long as they don't get thrown out the windows, and seatbelts aren't suited to the nature of rail incidents as against vehicular ones, causing more injuries. How this may relate to trams/light rail I can't say. This work was informed by a significant number of heavy rail incidents.

 

Re: coach design it certainly was the case with some vehicles that the driving position and boot were often structurally supported on outriggers from the main chassis frame.  The traditional body-on-chassis construction where entirely different manufacturers were responsible for designing and building their own halves of the vehicle in effect encouraged this.

 

Current legislation has improved the structural safety of passenger-carrying road vehicles.  This has gone hand in hand with the trend in recent years for a manufacturer to offer a "whole vehicle" even if the component parts are still supplied separately.  Thus the semi-integral Bova coaches are mounted on DAF running units but are fully assembled by the Bova business.  The same is true for buses and we may be assured that the vehicles we travel in now are inherently far safer than those of 20 or 50 years ago.  Coaches are subject to rollover regulations and must meet minimum structural standards.  Buses must be able to pass the tilt test albeit this is a static test with a full load of dummy weights upstairs and none downstairs.  I myself have ridden on the (now-closed) London Transport Chiswick skid-pan aboard both RT and RM vehicles.  Both skidded and tipped alarmingly to the viewer though wheels never left the ground and most of the "tilt" was in the suspension.  But on board the buses one was comfortably able to remain seated.  

 

The issue of seat belts is widely discussed and researched.  Suffice to say here that I believe the UK regulations have struck the correct balance between risk, practicality and common sense.  Insofar as this applies to passenger-carrying road vehicles the local bus is effectively exempt on the grounds that the risk to passengers is so low that it is outweighed by the inconvenience of having constant buckling up and unbuckling as the bus stops so frequently.  Extremely few passengers, as a proportion of total carried, are injured (let alone killed) on buses making them one of the safest modes of road transport.  Trains operate under similar considerations in that they are statistically extremely safe, the needs of passengers make the three-point belt unsuitable and in any case they don't offer the right sort of protection.  Lap belts are arguably even worse in this application.

 

Trams operate somewhere between road and rail being a bit of both.  Seat belts are not required on the grounds that passengers are frequently boarding and alighting, as with a bus, the risk is extremely low, and in any case what is to protect standing passengers?  Trams and Light Rail Vehicles (you tell me the difference) can accelerate and brake at quite fierce rates but seated passengers are not normally troubled by this and standing passengers should reasonably be holding onto something provided for that purpose.  

 

My understanding of the current legislation is that there is no thinking to bring in seat-belts (whether mandatory or otherwise) for local buses and trams because the level of inconvenience and potential for increased stop dwell times far outweighs the statistical level of risk.  In other words if a double-decker bus or a tram had to wait for everyone to belt up before moving off, and passengers were not permitted to unbelt until the thing stopped, then each and every journey would become intolerably long and slow, roads would become more, not less, congested and passengers would likely be disinclined to travel.  If bus and tram travel were anything like as high-risk as by private car then we would be looking at a very different industry.

[martin_wynne]

A system such as TPWS or ZUB, which relies on the timing between two locations, may be unsuitable for tram application because of the much more rapid changes of speed that are possible.  If needed on any street sections it would also be difficult to fit trackside equipment there. 

 

Trams stop and start frequently. One extra stop isn't going to make much difference to journey times.

 

Would it be practical to bring a tram to stand before continuing where there is a big reduction in permitted speed? You could even build a tram stop there.

 

It would be a lot cheaper than fitting a full TPWS system.

 

Martin.

[edcayton]

 Re: coach design it certainly was the case with some vehicles that the driving position and boot were often structurally supported on outriggers from the main chassis frame.  The traditional body-on-chassis construction where entirely different manufacturers were responsible for designing and building their own halves of the vehicle in effect encouraged this.

 

Current legislation has improved the structural safety of passenger-carrying road vehicles.  This has gone hand in hand with the trend in recent years for a manufacturer to offer a "whole vehicle" even if the component parts are still supplied separately.  Thus the semi-integral Bova coaches are mounted on DAF running units but are fully assembled by the Bova business.  The same is true for buses and we may be assured that the vehicles we travel in now are inherently far safer than those of 20 or 50 years ago.  Coaches are subject to rollover regulations and must meet minimum structural standards.  Buses must be able to pass the tilt test albeit this is a static test with a full load of dummy weights upstairs and none downstairs.  I myself have ridden on the (now-closed) London Transport Chiswick skid-pan aboard both RT and RM vehicles.  Both skidded and tipped alarmingly to the viewer though wheels never left the ground and most of the "tilt" was in the suspension.  But on board the buses one was comfortably able to remain seated.  

 

The issue of seat belts is widely discussed and researched.  Suffice to say here that I believe the UK regulations have struck the correct balance between risk, practicality and common sense.  Insofar as this applies to passenger-carrying road vehicles the local bus is effectively exempt on the grounds that the risk to passengers is so low that it is outweighed by the inconvenience of having constant buckling up and unbuckling as the bus stops so frequently.  Extremely few passengers, as a proportion of total carried, are injured (let alone killed) on buses making them one of the safest modes of road transport.  Trains operate under similar considerations in that they are statistically extremely safe, the needs of passengers make the three-point belt unsuitable and in any case they don't offer the right sort of protection.  Lap belts are arguably even worse in this application.

 

Trams operate somewhere between road and rail being a bit of both.  Seat belts are not required on the grounds that passengers are frequently boarding and alighting, as with a bus, the risk is extremely low, and in any case what is to protect standing passengers?  Trams and Light Rail Vehicles (you tell me the difference) can accelerate and brake at quite fierce rates but seated passengers are not normally troubled by this and standing passengers should reasonably be holding onto something provided for that purpose.  

 

My understanding of the current legislation is that there is no thinking to bring in seat-belts (whether mandatory or otherwise) for local buses and trams because the level of inconvenience and potential for increased stop dwell times far outweighs the statistical level of risk.  In other words if a double-decker bus or a tram had to wait for everyone to belt up before moving off, and passengers were not permitted to unbelt until the thing stopped, then each and every journey would become intolerably long and slow, roads would become more, not less, congested and passengers would likely be disinclined to travel.  If bus and tram travel were anything like as high-risk as by private car then we would be looking at a very different industry.

 

As I understand it some passengers can be carried standing up, and can go up and down stairs whilst the bus is moving.  sorry

 

Ed

Edited November 12, 2016 by edcayton

[dhjgreen]

A typical modern tram is 70 seated, 130 standing

[ruggedpeak]

It will be interesting to understand more about the nature of tram design. I am assuming they have some degree of road relating impact protection as collisions between trams and other road vehicles are quite common, mainly due to other road users ignoring the tram related signage.

 

BTP and the Met quite often do tram crossing operations targetting drivers who ignore the crossing lights. In the past it was a lottery for the drivers caught, as BTP offered driver awareness courses instead of the points. The Met didn't at the time. So it depended upon whether they were stopped by a BTP or Met officer as to whether you got points - a few people weren't happy to watch someone else get a course when they got points. Of course if they hadn't run the lights it wouldn't matter. Emergency services drivers have to stop and turn off their warning equipment at tram crossings exactly as if they are level crossings (i.e. can't be used as give way like a traffic light). Trainee drivers are deliberately taken through Croydon to experience the roads with trams on. Running a tram crossing is a major fail.

 

As an aside, injuries on buses are reported by the Police on London. It is quite common for the police to be called to a passenger who has been injured as a result of the bus driver making an emergency stop. These are reported as injury collisions. I'm not sure if this is purely a TfL thing or UK wide.

[jamie92208]

 

 

As an aside, injuries on buses are reported by the Police on London. It is quite common for the police to be called to a passenger who has been injured as a result of the bus driver making an emergency stop. These are reported as injury collisions. I'm not sure if this is purely a TfL thing or UK wide.

Though it's now 14 years since I retired the standard definition of a road traffic accident included a phrase that ran along these lines "If due to the presence of a motor vehicle on a road injury is caused to any person either in or on the vehicle"  Thus  passenger injury is a road accident and reportable.  I can' remember the rest of the full definition, I did learn it in basic training in 1973 but I've slept since then.   As far as I remember it allows you to exchange details with the other driver either at the scene or within 24 hours after that you have to report it.  IIRC then if there is injury it is always reportable.

 

Jamie

Edited November 12, 2016 by jamie92208

[ruggedpeak]

As someone with some knowledge of investigating serious road collisions and the legal processes, there have been various bits of nonsense and some accurate comments on the situation.

 

Arresting a suspect in England falls under the Police & Criminal Evidence Act (PACE) in many but not all cases.....

BTP state a man was arrested on suspicion of manslaughter. He has been released on bail until May.

 

http://media.btp.police.uk/r/13403/updated_statement_on_tram_derailment_-_croydon

 

http://media.btp.police.uk/r/13405/updated_statement_on_tram_derailment_-_croydon

 

Clearly manslaughter is one of the most serious criminal offences, so I'll not comment/speculate any further on this aspect of the tragedy.