Croydon Tram Accident

[34theletterbetweenB&D]

Here's a couple from Nottingham:

 

This is where trams leave the city centre street running section, and head north towards the scenic delights of Bulwell and Hucknall...

 My sole experience of modern UK tram systems is Nottingham's; and this incident brought very much to mind the abrupt contrast on that system between making good speed on the GCR railway section, and the abrupt transition to the 'right angle' bends of street running.

 

We have to wait and see what the recommendations are, but my own feeling is that the street sections and their approaches need a speed limiter actuated on the tram. There's plenty of tech available to enable this, and it's a no brainer to prevent such incidents.

[Titan]

This is speculation. There could have been a fault with the tram. It also looks as though there was an "accident waiting to happen" with this corner, but can we please wait for the full enquiry results?

 

Ed

 

Seeing as the RAIB interim report has stated that no fault was found with the tram, then your accusation of speculation is somewhat wide of the mark. There are far too many people who will make these accusations of speculation/requests not to speculate etc. at the slightest excuse, as if it is some sort of competition as to who can be the most sanctimonious.

[kevinlms]

I don’t think the dictionary definition of accident is the issue. The problem people have is the way that the word is received by many. Regardless of its dictionary meaning there is reason to believe that use of the word in relation to train and air crashes, ships sinking, power stations blowing up etc invokes responses to the effect that accidents can’t be avoided, accidents happen, c’est la vie, etc. Which is not helpful to safety, whether or not it is justified in terms of the actual meaning of the word accident there is now an increasing reluctance to use the word accident to describe these sort of events (noting that the RAIB, AAIB and MAIB all retain the word accident in their titles).

Yes its strange how many times the discussion comes up about the word 'accident'. There seems to be no evidence that the word 'accident' has any relevance to the cause of any incident, involving unintentional contact.

 

Yet discussion about kmh or mph, is brushed off as 'it doesn't matter, because the vehicle (tram) speedometer is marked in both systems'. My point is why have both systems in use? If you want to keep mph (and obviously the UK & USA do and indeed is their right), then drop the kmh signage altogether.

 

I wonder if the final report, will consider such possible confusion?

[Oldddudders]

Presumably tram drivers, like train drivers, but unlike you and me in our cars, have route-specific training, prior to "signing for" a line of route. Only then can they be trusted to take the tram solo. We all become familiar with roads that we drive regularly, so the road signs no longer register. We know where the 30 limit starts, we know where we have to give way, all that stuff. I suggest that putting new or relocated signs before this tiresome corner (it's rather more than a bend, clearly) will only be effective in the first few months. After that the signs will become a part of the scenery, and the drivers will seldom read them. Whether those who need to be seen to be acting will think that is enough remains to be seen. 

[Fat Controller]

Yes its strange how many times the discussion comes up about the word 'accident'. There seems to be no evidence that the word 'accident' has any relevance to the cause of any incident, involving unintentional contact.

 

Yet discussion about kmh or mph, is brushed off as 'it doesn't matter, because the vehicle (tram) speedometer is marked in both systems'. My point is why have both systems in use? If you want to keep mph (and obviously the UK & USA do and indeed is their right), then drop the kmh signage altogether.

 

I wonder if the final report, will consider such possible confusion?

The speed limit signs and the speedometers on the trams both use metric units, so I can't see any problem with this; the railway I work on uses metric units as well, and my UK drivers seem to cope with using this at work, then using the Imperial system when driving on UK roads.

[PatB]

The speed limit signs and the speedometers on the trams both use metric units, so I can't see any problem with this; the railway I work on uses metric units as well, and my UK drivers seem to cope with using this at work, then using the Imperial system when driving on UK roads.

 

Indeed. I remember noticing, back in 1980 or so, that the speed restriction signs on the Newcastle Metro were in km/h. At the time I thought this very novel. AFAIK the Metro has been operating safely for all the years since then, in spite of drivers having to swap between imperial when driving their cars and metric when at work.

 

As someone who has lived in both the UK and Australia I would suggest that the Brits are very adept at mentally switching between unit systems and even combining the two into weird hybrids without serious confusion arising. Indeed, it's so commonplace that most don't even register that they're doing it.  Whilst the RAIB report may note speed restriction unit confusion, I wouldn't experience the slightest surprise if it didn't.

Edited November 18, 2016 by PatB

[Reorte]

Presumably tram drivers, like train drivers, but unlike you and me in our cars, have route-specific training, prior to "signing for" a line of route. Only then can they be trusted to take the tram solo. We all become familiar with roads that we drive regularly, so the road signs no longer register. We know where the 30 limit starts, we know where we have to give way, all that stuff. I suggest that putting new or relocated signs before this tiresome corner (it's rather more than a bend, clearly) will only be effective in the first few months. After that the signs will become a part of the scenery, and the drivers will seldom read them. Whether those who need to be seen to be acting will think that is enough remains to be seen. 

Very true. Anything can become part of a subconcious routine if you're not careful, and there's always a chance that they'll be equally subconciously forgotten. Railway-wise running on yellow signals has been mentioned in another thread, with the risk that cancelling AWS becomes routine instead of something infrequent and hence conciously noticed. Infrequent warnings jolt people back to the job at hand wherever their mind was and are thus much more effective since they can't be left to the subconcious. The subconcious is good for doing routine things that don't cause much trouble if a mistake is made (imagine how much hassle driving a car would be if you had to really think about every gear change - that's why learning to drive is a hassle).

 

I think that this is why systems like TPWS are effective. You don't really notice it's there unless you really need to notice (at least that's what my outsider knowledge of it tells me).

[Talltim]

As someone who has lived in both the UK and Australia I would suggest that the Brits are very adept at mentally switching between unit systems and even combining the two into weird hybrids without serious confusion arising. Indeed, it's so commonplace that most don't even register that they're doing it.

4mm/foot !

Edited November 18, 2016 by Talltim

[ruggedpeak]

The speed limit signs and the speedometers on the trams both use metric units, so I can't see any problem with this; the railway I work on uses metric units as well, and my UK drivers seem to cope with using this at work, then using the Imperial system when driving on UK roads.

And people who drive boats and planes operate in knots and seem to cope.

[Budgie]

And people who drive boats and planes operate in knots and seem to cope.

But knots are metric units, being 1.852 kilometres per hour exactly.

 

For more information see Wikipedia.

[royaloak]

 if the driver was travelling at the speed quoted ( it was qualified with 'evidence so far' )and knew it then he was definitely unprepared and, if other drivers including this one, could say that they always took the bend at that speed and had to or they would be late arriving elsewhere and the speed was accepted as the norm by usage, then the derailment and overturn could be considered as unexpected.

Luckily the railways dont work like that, the speed limit is just that, a limit and any exceeding of said speed limit could end with a visit to Management, I would hope the trams would work to the 'rail' way and not the norm on the roads where the speed limit seems to be the minimum allowed.

[jjb1970]

I'd be surprised if the use of both mph and kph is a causal factor in this case, however I do think that mixing imperial and metric units is bad practice as it can cause confusion, lead to mistakes and it just introduces another potential trigger for things to go wrong.

[rockershovel]

I don't have anything to add, regarding the specific case but I do have a lot more experience than I want to have, of industrial accidents involving repetitive process cycles.

 

My experience has been that where an incident of this sort occurs in an established process, then the first point of enquiry would be previous Incidents or Near Miss Reports of similar issues, at the location or at similar locations elsewhere in the network. The next thing would be the records of the driver in question, and other drivers in the same location. The next thing would be timekeeping - are there any patterns of lost time being recovered, or of a tendency to lose time in any particular location or section? I would also look at Tool Box Talk records, or their equivalent, because they tend to reflect issues which are known, but not necessarily reported.

 

Large networks running repetitive operations or cycles tend to develop patterns, which may not be evident from the routine reporting but can be found if you look in the right way. TBH, if the driver genuinely WAS driving as far in excess of the limit, I would think it likely that there would be a pattern of such things over time.

[kevinlms]

The only ones confused are those complaining about it in this thread

 

As has been explained, both the speedo and the signs are in kph, so there is no ambiguity possible. The remarks on road speeds being marked in mph is completely irrelevant, as the accident didn't happen on a public road

Absolutely, I'm not confused. I just cannot understand why, one system or the other isn't standardised on. MPH or KMH, take your pick. As far as I'm aware, there is no plans to make British roads etc, metric, so why use KMH for trams at all?

 

Edit to add.

 

Not one of you have so far put forward a reason, why trams should use the metric system for speed limits.

Edited November 18, 2016 by kevinlms

[Gwiwer]

Mixed units of measurement?  The London Underground has been using kilometres and km posts for many years and even has a "false zero" these days as 0.0 was at the former Ongar terminus.  But trains still travel and speeds are restricted in mph including very large circular warning signs.

 

I don't see much scope for confusion.  It is not the unit of measurement which is in question but the actual velocity of the tram.  If a driver has mistaken 50kmh for 50mph then the tram has been travelling overspeed for some distance  and uphill to boot.  Trams can achieve such performance levels even when fully loaded.  But the question then is why has no passenger on board taken any action to alert the driver to this excessive speed which would surely have been noticed?

[Fat Controller]

Absolutely, I'm not confused. I just cannot understand why, one system or the other isn't standardised on. MPH or KMH, take your pick. As far as I'm aware, there is no plans to make British roads etc, metric, so why use KMH for trams at all?

 

Edit to add.

 

Not one of you have so far put forward a reason, why trams should use the metric system for speed limits.

Perhaps because, when the first of the new generation arrived, they were bought more-or-less off the shelf from suppliers in mainland Europe, and came with metric speedos, instruction manuals etc, and no-one could be bothered to change it?

[JDW]

Sorry, bu I don't get where the confusion about metric/imperial is coming from.  If the signs are in metric, and say 50, the driver will look at his metric speedo and it will say 50.  He won't look at it and think "oooh, I can do 50mph" and drive at 80kmh (roughly= 50mph).  He'll do 50.  And if its the inverse, the sign says 50mph, and he were silly enough to forget, he'd be doing 50kph which is 30mph, well below the limit.  The two are sufficiently different that any competent professional driver can tell (roughly) whether they are doing 50mph or 50kph.  Our buses have speedos marked in both.  Some are marked with MILES and Kilometres, like UK cars, some have KILOMETRES and Miles, where the Kms are in big on the outside and miles in smaller inside, but even then, I've never found myself confused as to which is which or accidentally doing 50mph instead of 50kph, you should have enough awareness of your vehicle to realise that one is substantially faster/slower than the other.  I've driven across in to France, or from N.I. to Eire, and still its hard to confuse - if you pass a 50 sign in a town centre, its unlikely to mean 50mph!  Maybe I'm wrong, maybe it was a contributory factor, I think all this talk of confusion between the two is somewhat clutching at straws and trying to find a problem where none exists.  Especially on a route the driver is familiar with, and where he knows approximately what speed he should be doing, probably without looking at the speedo, as it becomes intuitive after dozens, hundreds of repetitions, just like steam crews could gauge their speed before speedos were fitted.

[kevinlms]

Perhaps because, when the first of the new generation arrived, they were bought more-or-less off the shelf from suppliers in mainland Europe, and came with metric speedos, instruction manuals etc, and no-one could be bothered to change it?

But earlier someone said that they were fitted with dual measurements on the speedometers. That would hardly be a standard fitting for a product made in Austria. So it would suggest that a dual speedometer was a specific request.

 

Edit to add

 

I'm sure I saw someone post that the speedos were marked in both, but if not the case, I accept that.

Edited November 19, 2016 by kevinlms

[Dagworth]

But earlier someone said that they were fitted with dual measurements on the speedometers. That would hardly be a standard fitting for a product made in Austria. So it would suggest that a dual speedometer was a specific request.

I've not seen anything anywhere on this thread to suggest that the Croydon trams speedos are marked in anything other than kph.

 

Again I will quote from the Tramlink website which is the best on-line reference for questions relating to Croydon trams. just a HUGE shame that the author is no longer with us.

 

https://croydon-tramlink.co.uk/info/trams/control.shtml

 

 

A speedometer in km/h is provided to the right of the Vecom. Trams are limited by speed limiters to just over 80kph which is the maximum speed on any part of the system.

 

Andi

Edited November 19, 2016 by Dagworth

[kevinlms]

Sorry, bu I don't get where the confusion about metric/imperial is coming from.  If the signs are in metric, and say 50, the driver will look at his metric speedo and it will say 50.  He won't look at it and think "oooh, I can do 50mph" and drive at 80kmh (roughly= 50mph).  He'll do 50.  And if its the inverse, the sign says 50mph, and he were silly enough to forget, he'd be doing 50kph which is 30mph, well below the limit.  The two are sufficiently different that any competent professional driver can tell (roughly) whether they are doing 50mph or 50kph.  Our buses have speedos marked in both.  Some are marked with MILES and Kilometres, like UK cars, some have KILOMETRES and Miles, where the Kms are in big on the outside and miles in smaller inside, but even then, I've never found myself confused as to which is which or accidentally doing 50mph instead of 50kph, you should have enough awareness of your vehicle to realise that one is substantially faster/slower than the other.  I've driven across in to France, or from N.I. to Eire, and still its hard to confuse - if you pass a 50 sign in a town centre, its unlikely to mean 50mph!  Maybe I'm wrong, maybe it was a contributory factor, I think all this talk of confusion between the two is somewhat clutching at straws and trying to find a problem where none exists.  Especially on a route the driver is familiar with, and where he knows approximately what speed he should be doing, probably without looking at the speedo, as it becomes intuitive after dozens, hundreds of repetitions, just like steam crews could gauge their speed before speedos were fitted.

OK, lets forget the 'confusion/no possibility of confusion' angle, because that isn't the main point of my argument.

 

My point is, why have metrics marked anywhere on the tram system? Its as simple as that, within a country that exclusively uses MPH as speed limits, on roads. It isn't as if the trams are going to be used anywhere else.

[Dagworth]

[Titan]

No, but it probably has eluded you that getting a series of mph speedo's made for just Tramlink would make them each bl00dy expensive and would have increased the costs considerably, 

 

Since when has swapping a speedo dial been expensive compared to the cost of a tram? Citation please? If it adds more than 0.01% to the cost of the entire tram i would be amazed!

[phil-b259]

I'd be surprised if the use of both mph and kph is a causal factor in this case, however I do think that mixing imperial and metric units is bad practice as it can cause confusion, lead to mistakes and it just introduces another potential trigger for things to go wrong.

 

There is no confusion.

 

Trams deliberately have their own system of signage independent of that used by motor vehicles and the adoption of metric measurements is part of that desire to keep the systems separate.

 

As others have indicated all Trams used in the UK are designed and built in Europe where kph is the standard speed measurement and which is thus embedded in all the trams systems. To vary this, while technically possible, bumps up the purchase price considerably as the tram is then not an 'off the shelf item' using standard parts. Adopting imperial speeds will also have an impact on spares and servicing costs due to the bespoke nature of some components..

 

As an aside you should note that motor manufactures refused to make special speedometers for the Irish market when the Republic changed from mph to kph for speed limits - citing it being too costly and the market too small. Thus the choice was a straight kph version as used in the rest of Europe or the British one with big mph figures and smaller kph ones inside that with the former selected as the required to be compliant one under the vehicle construction regs for the Republic. this now means that an increasing number of cars registered in the republic have no way of accurately letting drivers know if they are complying with the speed limits in Northern Ireland which retains mph.

 

It should also be noted that on the Newcastle Metro, all its speeds are indicated in kph - yet they also share the mainline to Sunderland which has both imperial and metric signage without any issues occurring as a result.

 

HS1 also has metric speed limits - but I have yet to hear of a driver becoming 'confused' when switching to or from imperial at Ashford.

Edited November 19, 2016 by phil-b259

[kevinlms]

Since when has swapping a speedo dial been expensive compared to the cost of a tram? Citation please? If it adds more than 0.01% to the cost of the entire tram i would be amazed!

Especially as these days a laser produced clear label, could be fitted over! Even in the far off days of dual marked speedometers in Australia, the thing was a printed disc, marked accordingly.

 

But this part of the thread is just plain ridiculous, from the 'there couldn't possibly be any confusion' lobby. Insulting even, in some of the comments.

 

 

"The only ones confused are those complaining about it in this thread "

 

 

 

A plane fairly recently made a successful emergency landing (in Canada IIRC), where the plane had run out of fuel. The mistake occurred, because of confusion over imperial/metric volumes of fuel. I think it could be successfully argued that, airline pilots are significantly higher trained, than tram drivers operating on one system. No disrespect to tram drivers intended, just pointing out a perspective.

 

A reference for those, who think it is just a matter of training drivers/pilots to know the difference.

 

https://en.wikipedia.org/wiki/Gimli_Glider

 

 

I'll leave the rest of you, to go back to the much more serious argument, over the use of the word 'accident'!

[kevinlms]

There is no confusion.

 

Trams deliberately have their own system of signage independent of that used by motor vehicles and the adoption of metric measurements is part of that desire to keep the systems separate.

 

 

No, they use the metric system, because seemingly its cheaper to buy in 'ready to roll' trams from Europe. You went on to say exactly that.