Croydon Tram Crash

[AlterEgo]

For me it is not a case that the curve needs to be re - designed, it is that as I have stated previously in this thread safety warning signs before getting to the end of the tunnel need to be be put up and the whole of the Croydon Tramlink system needs to have something similar to TPWS fitted within it that can also be used with the sections of tramway that exist within any roads that it ravels along.

The problem is not with the trams themselves, it is with the Infrastructure that the trams run on.

How does a warning chevron on a tramway or road protect against a driver blacking out or falling asleep?

 

[All Line Rover]

The problem is not with the trams themselves, it is with the Infrastructure that the trams run on.

If a Pendolino rolling down an embankment (and thankfully not falling off a viaduct) results in significantly fewer injuries than a tram falling on its side, it shouldn't be too surprising that people might question the crash-worthiness of these trams.

 

[Domeyhead]

Can we refrain from speculation please? It is neither necessary nor helpful.

I was waiting for this. WHat do you think forums are for? What do you think this forum is for? Are you saying that we should all shut down this thread until a public enquiry completes its work in 2019 and pronounces which of the one or two theories already propounded actually turned out, on the weight of evidence, to be the most likely contributory cause? What is it with railway forums that the veil of censoriuous silence is somehow seen as healthy? There is even a word for it - speculation. We are allowed to speculate, for now.

 

[westcoaster]

If a Pendolino rolling down an embankment (and thankfully not falling off a viaduct) results in significantly fewer injuries than a tram falling on its side, it shouldn't be too surprising that people might question the crash-worthiness of these trams.

We would need to see what internal damage there is in the affected tram, then if anything penertraded the passenger saloon (ballast, rails, stanchions) these would all affect survivability.
Low floor trams have a lot more space for a person to be chucked around than a high floor tram.

 

[Antman]

If a Pendolino rolling down an embankment (and thankfully not falling off a viaduct) results in significantly fewer injuries than a tram falling on its side, it shouldn't be too surprising that people might question the crash-worthiness of these trams.

Pointless comparison.

 

[heart-of-wessex]

Metrolink trams also have top speed of 50mph and they frequently achieve it on the segregated lines.

Someone called in Radio 2 earlier today as that was on discussion, anyway caller said you can see through a window to the cab and you can see the speedometer, and said on one stretch (Morden to somewhere or something) they regularly go up to 70mph.

70!? Flippin heck is that even possible?
Not sure if that is correct or if he was reading Kph, do the speedo's have both Mph and Kph?

 

[westcoaster]

Someone called in Radio 2 earlier today as that was on discussion, anyway caller said you can see through a window to the cab and you can see the speedometer, and said on one stretch (Morden to somewhere or something) they regularly go up to 70mph.

70!? Flippin heck is that even possible?
Not sure if that is correct or if he was reading Kph, do the speedo's have both Mph and Kph?

Iirc the tram link runs on KPH

 

[Llanigraham]

Someone called in Radio 2 earlier today as that was on discussion, anyway caller said you can see through a window to the cab and you can see the speedometer, and said on one stretch (Morden to somewhere or something) they regularly go up to 70mph.

70!? Flippin heck is that even possible?
Not sure if that is correct or if he was reading Kph, do the speedo's have both Mph and Kph?

I suspect that they are only marked in KPH, so the viewer was making an incorrect assumption.

 

[BestWestern]

I suspect that they are only marked in KPH, so the viewer was making an incorrect assumption.

Indeed. There will now be a glut of sensationalist, hysterical, scaremongering empty waffle, from all manner of totally uninformed sources, trying to suggest that trams are inherently dangerous. Just like the ridiculous suggestion mentioned above that a tram somehow lifted half off the rails on the same curve on an earlier occasion, as if it were a car in a Bond film. I would suggest that no such 'stunt driving', impressive though it would be, actually happened.

I'm reminded of the National Express coach crash a few years ago invovolving a Neoplan Skyliner double decker, after which at least one tabloid decided to try and raise some hysteria by suggesting that double deck coaches must be unsafe, as if one accident made them a major health hazard. Amusingly, the idiot journo seemed to have failed to appreciate that several thousand double decker buses also operate in the UK, and these would surely be equally as unsafe if that were indeed the case. Sadly, despite being a clearly desperate headline, the efforts of the press were sufficient to persuade NatEx to remove 'deckers from its routes. No doubt we'll see all manner of ambitious and tenuous 'safety' tram stories coming up for a short while now.

 

[Domh245]

Pointless comparison.

Not entirely. For the layperson, Grayrigg might have come to mind as the last fatal crash, and as noted, the faster (read: more dangerous) crash only had one fatality compared to the slower (read: safer) crash, which has had 7. It is only natural to then ask questions.

A lot of the reports are suggesting that the passengers that lost their lives were ejected out of the tram during the incident, so it does raise questions about whether or not it is better to have easily breakable windows for evacuation, or stronger windows for passenger retention in rollovers. That'll probably get looked at in the RAIB report.

Someone called in Radio 2 earlier today as that was on discussion, anyway caller said you can see through a window to the cab and you can see the speedometer, and said on one stretch (Morden to somewhere or something) they regularly go up to 70mph.

70!? Flippin heck is that even possible?
Not sure if that is correct or if he was reading Kph, do the speedo's have both Mph and Kph?

Morden Road to Phipps Bridge. And as others have said, they're marked in kph, I think that Metrolink are the only tram system that work in mph.

 

[507 001]

It is almost impossible to make an M5000 exceed 80kph/50MPH, they have a limiter.

I would imagine that a CR4000 is similar in that regard.

The person in question would have been reading a metric speedometer.

 

[snowball]

For info: the German thread on this topic (much briefer and more factual) refers to similar accidents in Duesseldorf and (years ago) Stuttgart.
http://http://www.drehscheibe-online.de/foren/read.php?5,7990439

I think you need to edit the beginning of that link.

 

[Antman]

Not entirely. For the layperson, Grayrigg might have come to mind as the last fatal crash, and as noted, the faster (read: more dangerous) crash only had one fatality compared to the slower (read: safer) crash, which has had 7. It is only natural to then ask questions.

A lot of the reports are suggesting that the passengers that lost their lives were ejected out of the tram during the incident, so it does raise questions about whether or not it is better to have easily breakable windows for evacuation, or stronger windows for passenger retention in rollovers. That'll probably get looked at in the RAIB report.



Morden Road to Phipps Bridge. And as others have said, they're marked in kph, I think that Metrolink are the only tram system that work in mph.

Without being too graphic in an accident of this nature people will inevitably be thrown around inside the tram.
--- old post above --- --- new post below ---

Indeed. There will now be a glut of sensationalist, hysterical, scaremongering empty waffle, from all manner of totally uninformed sources, trying to suggest that trams are inherently dangerous. Just like the ridiculous suggestion mentioned above that a tram somehow lifted half off the rails on the same curve on an earlier occasion, as if it were a car in a Bond film. I would suggest that no such 'stunt driving', impressive though it would be, actually happened.

I'm reminded of the National Express coach crash a few years ago invovolving a Neoplan Skyliner double decker, after which at least one tabloid decided to try and raise some hysteria by suggesting that double deck coaches must be unsafe, as if one accident made them a major health hazard. Amusingly, the idiot journo seemed to have failed to appreciate that several thousand double decker buses also operate in the UK, and these would surely be equally as unsafe if that were indeed the case. Sadly, despite being a clearly desperate headline, the efforts of the press were sufficient to persuade NatEx to remove 'deckers from its routes. No doubt we'll see all manner of ambitious and tenuous 'safety' tram stories coming up for a short while now.

There has been plenty of that already on social media..............."I always said that corner was dangerous" etc etc. Well surely if they really thought it was that dangerous they would avoid using the tram?

 

[bramling]

If a Pendolino rolling down an embankment (and thankfully not falling off a viaduct) results in significantly fewer injuries than a tram falling on its side, it shouldn't be too surprising that people might question the crash-worthiness of these trams.

This is a valid and reasonable question, although there may well be valid and reasonable answers. One factor may well be that the derailed Pendolino, if I remember rightly, was comparatively lightly loaded.
--- old post above --- --- new post below ---

I was waiting for this. WHat do you think forums are for? What do you think this forum is for? Are you saying that we should all shut down this thread until a public enquiry completes its work in 2019 and pronounces which of the one or two theories already propounded actually turned out, on the weight of evidence, to be the most likely contributory cause? What is it with railway forums that the veil of censoriuous silence is somehow seen as healthy? There is even a word for it - speculation. We are allowed to speculate, for now.

Personally I have no problem with speculation. There is a legitimate interest in these sorts of incidents, and in general the standard of discussion on a forum such as this will be far more informed than might be expected elsewhere. What I would say is people should ensure that when they do speculate then they make sure this is clear from their wording, and do not post guesses and assumptions in a way which makes them look like facts. Also try to keep things factual as far as possible, so only post stuff if pretty sure of factual accuracy and provide source references as far as possible. To be fair, this thread has been pretty reasonable in my view.

You can bet that every messroom across the London transport system has probably discussed the incident today. Where I am it's certainly been discussed, and I can say that a lot of the stuff posted on here is far more factual and sensible than what I've heard elsewhere.
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We shall see whether that speed limit survives the aftermath. I was very surprised to learn that it was allowed when it means the expected speed matches the capability of the tram. Just because my car (and I have a very modest one) is capable of 120 mph doesn't mean it should ever be attempted.

I will make a general comment here on frequencies. Until quite recent times and the introduction of new trams, especially with a tram 'missing' following the fatal accident involving a bus being driven in a criminal manner, there has been pressure on the Tramlink operators to get higher frequencies as the passengers using the system increase inexorably. Wimbledon only got an increase by diverting the more frequent 3 route from Addington to it rather than the 1 from Elmers End, and, as anyone who has ever been involved in public transport scheduling realises, if the resource and the distance to be covered is finite, then the only way to increase the frequency is by speeding up between stops, once you have got terminal times down to a minimum (given the problems at Wimbledon, it's obvious that has been done). In theory, you could spend less time at each intermediate stop, if it were not for those pesky passengers refusing to act like robots: in any case, with the increase in passenger numbers per tram journey this is an impossible dream. From memory, when Croydon Tramlink started in 2000 frequencies were every 7 minutes to Addington and every 10 minutes to Wimbledon, Elmers End and Beckenham weekday peak and shopping hours. Over the intervening years frequencies decreased, if anything, certainly to every 12 minutes from 10, and to 8 from 7, for some time. Now they are back up again, with the new 4 route increasing the Elmers End to Therapia Lane frequency. Now, whether the passengers and people living on the route(s) being quoted in the media are all being wise after the event, or plain misguided, there is an impression given of the system having speeded up over the last few months to, in the opinion of some, a dangerous level. The whole system and its operation will now come, rightfully, under enormous scrutiny.

Whilst you make a reasonable point, I think this introduces a lot of difficulties. If it turns out the driver made no attempt to reduce the speed of the tram at all (for whatever reason), then the speed limit is not really relevant. Conversely, if it turns out to be a braking misjudgement then perhaps there could be a case for looking at whether the driver felt under pressure. *But*, either way, as with the Moorgate accident, some kind of engineered safeguard is the way to go. The way I see it, the only ways to go that would completely remove the possibility of overspeed round the curve are (1) a continuous ATP system enforcing speed limits, or (2) some kind of trainstop trap, like found on the Underground or with TPWS. In the latter case then some form of risk assessment would have to be done over the entire system to identify risky locations -- and of course this raises the possibility that other systems in the UK could have similar risky locations (I can think of some in Manchester for a start).

Remember that even if the speed limit through the tunnels was halved from 50 mph to 25 mph, you could still have a major incident on the curve if nothing was done to slow the tram to 12 mph.
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I've never heard such rubbish.

A tram travelling at 80kph or whatever the speed is there stands no chance of avoiding a horrendous derailment if a driver for whatever reason fails to slow his tram down to the required 20kph for that bend.

A bus driver travelling at 80kph fails to slow to 20kph for a bend the outcome is entirely different. It's not on rails for one thing.

The risk assessment of a bus going round a bend and a tram going round a tight curve are somewhat different so please let's not make such stupid comments and think a little.

I don't see why his comment is so off the wall.

The characteristics of a tram system is such that, although it runs on rails, it has a number of features which are more akin to a road vehicle running on a road. Driving on sight for a start (in most cases - Tyne & Wear Metro, DLR and Metrolink are/were exceptions), no speed supervision, and the ability to deploy a harsher rate of braking compared to a traditional train. Combined with this are features like more aggressive curves and gradients, and a greater possibility of encountering obstructions such as people or road vehicles.

It doesn't make much difference whether it's a bus or tram - a vehicle trying to negotiate a very sharp curve at 50 mph is going to have a similar outcome, it's probably going to career out of control and be a danger to both its occupants and anyone in its path. It's down to the designers and operators to implement mitigation measures, in various forms (both in terms of engineering safeguards and human factors safeguards).

 

[the sniper]

Without being too graphic in an accident of this nature people will inevitably be thrown around inside the tram.

Yes, obviously. Being thrown around inside the vehicle is inevitable. Being thrown out of a rail vehicle is not inevitable. The rail industry has long recognised this risk in the event of an accident and as such modern mainline stock is designed to mitigate this risk, the success of this work was proven in the Grayrigg crash.

Given the various reports of happened to people onboard the tram, including those who sadly died, and knowing what tram windows are like in comparison to modern train windows, you have to imagine that this will form a reasonable part of the RAIB report beyond the initial cause of the accident.

 

[BestWestern]

Yes, obviously. Being thrown around inside the vehicle is inevitable. Being thrown out of a rail vehicle is not inevitable. The rail industry has long recognised this risk in the event of an accident and as such modern mainline stock is designed to mitigate this risk, the success of this work was proven in the Grayrigg crash.

Given the various reports of happened to people onboard the tram, including those who sadly died, and knowing what tram windows are like in comparison to modern train windows, you have to imagine that this will form a reasonable part of the RAIB report beyond the initial cause of the accident.

People being ejected through the windows of overturned heavy rail vehicles was a significant issue for a long time. It is only in the last few years though that the decision was made to move from breakable windows to aid escape, to toughened windows designed to retain pax inside the vehicle. This explains the general removal of the hammers previously always found throughout passenger saloons.

I agree that RAIB may well focus on that area, though I can't see a requirement to reglaze Britain's tram fleet. The risk of a tram overturning is minimal, far less than a train owing to the much lower impact speeds of a collision . And indeed lower than it would once have been even for a tram, given that most cars were double deckers on the original systems.

 

[SpacePhoenix]

Was reading that it's beleievd that there could potentially be more bodies underneath the tram.

From the overhead pictures there's a bulked rail. Would the initial tipping over have been a result of the centrifugal force or from the rail giving way?

 

[neonison]

From the overhead pictures there's a bulked rail. Would the initial tipping over have been a result of the centrifugal force or from the rail giving way?

The buckled rails seen on most of the overhead pictures is on the inbound line from Beckenham Junction direction. This is likely to have been buckled by the derailed tram sliding into it. I do not believe we have seen any pictures which show the running lines from New Addington as being damaged though the ballast in the 'six-foot' has been ploughed through. Those that need to will have already inspected the running lines for witness marks and I am certain all of the track geometry will be rechecked before the lines are reopened.

 

[Antman]

Was reading that it's beleievd that there could potentially be more bodies underneath the tram.

From the overhead pictures there's a bulked rail. Would the initial tipping over have been a result of the centrifugal force or from the rail giving way?

I suppose that must be a possibility, the tram is due to be removed today.

 

[RobShipway]

How does a warning chevron on a tramway or road protect against a driver blacking out or falling asleep?

For driver falling asleep you have TPWS, but that corner from what people have said in this thread has been taken to quickly even when the driver has been awake, which is why I think there should be a warning chevron a good distance before the corner, as you do with the highway code for cars and other vehicles on the road.

 

[Antman]

For driver falling asleep you have TPWS, but that corner from what people have said in this thread has been taken to quickly even when the driver has been awake, which is why I think there should be a warning chevron a good distance before the corner, as you do with the highway code for cars and other vehicles on the road.

I'm not sure that would really serve any useful purpose, drivers obviously know the network like the back of their hand.

 

[gsnedders]

Some TPWS-like system probably makes more sense to introduce sooner rather than later, if we're going to, before (2nd gen) tram networks expand further in the UK.

 

[Zoidberg]

The RAIB has updated its webpage to say that it:

... will provide a further update in the form of an interim report next week.

That's from https://www.gov.uk/government/news/fatal-tram-accident-in-croydon

Hopefully that will provide helpful information.

 

[westcoaster]

The RAIB has updated its webpage to say that it:



That's from https://www.gov.uk/government/news/fatal-tram-accident-in-croydon

Hopefully that will provide helpful information.

I know in the air reports there is normally an interim report to be released within a certain time line maybe the same with the RAIB.

 

[Scott M]

How can they prove the driver blacked out as opposed to simply over speeding?

 

[507 001]

This is a valid and reasonable question, although there may well be valid and reasonable answers. One factor may well be that the derailed Pendolino, if I remember rightly, was comparatively lightly loaded.
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Personally I have no problem with speculation. There is a legitimate interest in these sorts of incidents, and in general the standard of discussion on a forum such as this will be far more informed than might be expected elsewhere. What I would say is people should ensure that when they do speculate then they make sure this is clear from their wording, and do not post guesses and assumptions in a way which makes them look like facts. Also try to keep things factual as far as possible, so only post stuff if pretty sure of factual accuracy and provide source references as far as possible. To be fair, this thread has been pretty reasonable in my view.

You can bet that every messroom across the London transport system has probably discussed the incident today. Where I am it's certainly been discussed, and I can say that a lot of the stuff posted on here is far more factual and sensible than what I've heard elsewhere.
--- old post above --- --- new post below ---


Whilst you make a reasonable point, I think this introduces a lot of difficulties. If it turns out the driver made no attempt to reduce the speed of the tram at all (for whatever reason), then the speed limit is not really relevant. Conversely, if it turns out to be a braking misjudgement then perhaps there could be a case for looking at whether the driver felt under pressure. *But*, either way, as with the Moorgate accident, some kind of engineered safeguard is the way to go. The way I see it, the only ways to go that would completely remove the possibility of overspeed round the curve are (1) a continuous ATP system enforcing speed limits, or (2) some kind of trainstop trap, like found on the Underground or with TPWS. In the latter case then some form of risk assessment would have to be done over the entire system to identify risky locations -- and of course this raises the possibility that other systems in the UK could have similar risky locations (I can think of some in Manchester for a start).

Remember that even if the speed limit through the tunnels was halved from 50 mph to 25 mph, you could still have a major incident on the curve if nothing was done to slow the tram to 12 mph.
--- old post above --- --- new post below ---


I don't see why his comment is so off the wall.

The characteristics of a tram system is such that, although it runs on rails, it has a number of features which are more akin to a road vehicle running on a road. Driving on sight for a start (in most cases - Tyne & Wear Metro, DLR and Metrolink are/were exceptions), no speed supervision, and the ability to deploy a harsher rate of braking compared to a traditional train. Combined with this are features like more aggressive curves and gradients, and a greater possibility of encountering obstructions such as people or road vehicles.

It doesn't make much difference whether it's a bus or tram - a vehicle trying to negotiate a very sharp curve at 50 mph is going to have a similar outcome, it's probably going to career out of control and be a danger to both its occupants and anyone in its path. It's down to the designers and operators to implement mitigation measures, in various forms (both in terms of engineering safeguards and human factors safeguards).

Again, slightly ridiculous.

The line speed round the corner was 12mph. Not 50. Under normal circumstances no driver would attempt to get around that bend at 50.

Reducing the maximum speed that the vehicles can travel in areas where it is perfectly safe to travel at those speeds is not going to reduce the likely hood of a similar incident occurring.

For driver falling asleep you have TPWS, but that corner from what people have said in this thread has been taken to quickly even when the driver has been awake, which is why I think there should be a warning chevron a good distance before the corner, as you do with the highway code for cars and other vehicles on the road.

Pray tell, how do you expect a chevron board to enforce a speed limit?

The drivers know that the curve is there. They'll have driven round it countless times with an instructor before they are even allowed near it on their own.

It's not like a road by any stretch of the imagination. You can't just jump in and go. I drive for Metrolink, but I that doesn't mean I could go down to Croydon and drive there straight away.

All drivers, like on the big railway, must sign for the route and traction that they are driving.
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How can they prove the driver blacked out as opposed to simply over speeding?

Because of the nature of the incident.

If it was just a simple overspeed incident you might expect it to be 5-10 mph over. Not 30-40.

The nature of the incident suggests that there is a more complicated reason.

 

[Scott M]

--- old post above --- --- new post below ---

Again, slightly ridiculous.

The line speed round the corner was 12mph. Not 50. Under normal circumstances no driver would attempt to get around that bend at 50.

Reducing the maximum speed that the vehicles can travel in areas where it is perfectly safe to travel at those speeds is not going to reduce the likely hood of a similar incident occurring.



Pray tell, how do you expect a chevron board to enforce a speed limit?

The drivers know that the curve is there. They'll have driven round it countless times with an instructor before they are even allowed near it on their own.

It's not like a road by any stretch of the imagination. You can't just jump in and go. I drive for Metrolink, but I that doesn't mean I could go down to Croydon and drive there straight away.

All drivers, like on the big railway, must sign for the route and traction that they are driving.
--- old post above --- --- new post below ---


Because of the nature of the incident.

If it was just a simple overspeed incident you might expect it to be 5-10 mph over. Not 30-40.

The nature of the incident suggests that there is a more complicated reason.

So you'd rather not have safety features that could reduce the risk of a crash?

Some are suggesting the tram sped up - could be that the driver accidentally sped up instead of braking due to fatigue (more likely on an early morning shift such as this). I just feel "I blacked out" is too easy an excuse that is thrown around a lot.

 

[daikilo]

I'm not sure that would really serve any useful purpose, drivers obviously know the network like the back of their hand.

It is true, but sometimes the human brain "wanders" or becomes disorientated and something like chevrons or flashing warning lights can bring it back to the job at hand or the actual location. Of course, likely nothing visual will help if concentration is completely lost. A timed detonator placer might, but would need to be far enough before the curve to allow an adequate braking distance which could then lead to a slower running time.

 

[WatcherZero]

Black Box will also tell you if the driver was using other controls in the run up to and whether they attempted to activate brakes. If they did it would make black out less likely.

 

[Antman]

It is true, but sometimes the human brain "wanders" or becomes disorientated and something like chevrons or flashing warning lights can bring it back to the job at hand or the actual location. Of course, likely nothing visual will help if concentration is completely lost. A timed detonator placer might, but would need to be far enough before the curve to allow an adequate braking distance which could then lead to a slower running time.

It wouldn't do any harm in having them and as mentioned previously Manchester Metrolink has them, whether they have avoided any accidents is impossible to say but in all honesty I doubt it. Something that would bring the tram to a halt if it hadn't reduced speed sufficiently would be of far more use, how practical that is on a tram system I don't know.
--- old post above --- --- new post below ---

--- old post above --- --- new post below ---


So you'd rather not have safety features that could reduce the risk of a crash?

Some are suggesting the tram sped up - could be that the driver accidentally sped up instead of braking due to fatigue (more likely on an early morning shift such as this). I just feel "I blacked out" is too easy an excuse that is thrown around a lot.

But you haven't explained how such features would reduce the risk of a crash?

Fatigue is far more likely to occur later in the day but anyway there is little point speculating further about what the driver did or didn't do.