Croydon tram overturns - many injured, some trapped

It certainly could. The problem on big engineering problems are that legacy systems generally met a previously acceptable standard. The standard moves on but it is often considered not necessary to meet the new standard unless their is a significant change. Then you have the costs of demonstrating the new functionality is high enough integrity for the safety standards. It gets messy and costly. So unless there is a change of legislation or plant, systems tend to be treated as "if it ain't broke don't fix it". Loads of UK infrastructure works on this basis. Nuclear reactors are the perfect case many run on software that was obsolete decades ago and new engineers are being taught antique programming languages to maintain them. The problem is the safety case to move to current technology is so onerous and hard to demonstrate that it is easier to maintain the old system.

http://www.theregister.co.uk/2013/06/19/nuke_plants_to_keep_pdp11_until_2050/
 
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XeNoN89 said:
He said earlier that he was surprised it isn't completely auto like the DLR, I was referring to that rather than the auto speed limit part.
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Probably best to quote the original post that stated that, rather the the latest one which didn't to avoid confusion.
 
Still early days, but my suspicion is that the driver either fell asleep on the wheel a.k.a. bin lorry driver 1-2 years back, or he did a copy cat of the cargo truck rampage in Nice this year which is also a copy cat of the bin lorry driver (but deliberate).

Condolences to the dead and their families :(
 
robgmun said:
Speed limits could be programmed into the tram so that it couldn't go over 12mph on that bend for example. can't be that hard surely??
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It's also not that hard to slow down to 12mph either, given that no tram in the UK has crashed since the 1950's, so it was probably quite reasonably thought unnecessary to design such levels of automation into the system. Our heavy rail network doesn't automatically slow down on tight bends either and we've not had a train crash due to excessive speed on a tight bend in living memory!

It's very easy to use hindsight to say 'OMG WHY DIDNT THEY JUST' but why would you have even bothered to include such a feature prior to yesterday?
 
Bear in mind every system that you implement needs to be thoroughly tested, failsafe and idiot proof. There's a reason just about every train or tram in the UK is driven by the human. We can't trust the technology.
 
Caged said:
I think the combination of trams sharing space with non-tram traffic, and the idea that they are designed as a lower-cost option to a light railway mean that certain things like that do get left out.
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perhaps but I'm saying semi automated - as in force them to stop at stations and cap speeds at parts of the route - still needs a driver though given they mix with traffic



I do wonder, if this guy fell asleep at the wheel, was it because he was up all night watching the US election results?
 
Had one of my old housemates who moved that area "mark himself safe" on facebook, sounds like he may have been on the train, not had a response from him since.


You wouldn't think of using that feature unless you were in a situation I would expect?

Sounds like too fast for the bend.

Horrible on the run up to xmas, RIP
 
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DJMK4 said:
Had one of my old housemates who moved that area "mark himself safe" on facebook, sounds like he may have been on the train, not had a response from him since.


You wouldn't think of using that feature unless you were in a situation I would expect?

Sounds like a young driver and going too fast for the bend.

Horrible on the run up to xmas, RIP
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A lot of people are doing that.. no idea why they'd do it when they have not been on the tram. Weirdos
 
[TW]Fox;30199283 said:
It's also not that hard to slow down to 12mph either, given that no tram in the UK has crashed since the 1950's, so it was probably quite reasonably thought unnecessary to design such levels of automation into the system. Our heavy rail network doesn't automatically slow down on tight bends either and we've not had a train crash due to excessive speed on a tight bend in living memory!
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That's a little inaccurate (Pedant....).
Depending on the curve, speed restriction in force on the curve and other external factors (e.g. risk of incursion onto opposing running lines), there are two main ways whereby which speeds throughout a curve or similar may be regulated.

1. The provision of a permanent AWS (Automatic Warning System) magnet. This would generally be placed at the commencement of safe braking distance from the preceeding line speed, but obviously real-world distances don't always match this.
This will always trigger an in-cab alert, which must be cancelled within 5s, otherwise emergency brakes will be triggered.
Whilst this doesn't control speed per-se, it should provide the necessary jolt to an inattentive driver.

2. The provision of a set of TPWS (Train Protection and Warning System) speed monitoring loops. These get the average speed of the train, and apply emergency brakes if too fast, and would again be placed at a safe braking distance to the curve.

Neither of these will pro-actively monitor the speed within the curve, but aim instead to prevent the train entering the curve in an overspeed situation.

There will also be a degree of feedback to/ from the signaller (Both from lineside equipment and from other railway staff), so that if a train is already running overspeed, or does something unexpected, the signalling infrastructure can be used in order to slow the train appropriately.

Marginally related to this is the fail-safe principle, which is used wherever possible in railway design; For example, if the curve was thought to pose a high-risk of derailments and thus incursion onto other running lines, it would wherever possible be made part of a completely separate section, so that all other trains are held until said section is clear.

TLDR:
There are a whole bunch of different technologies and design considerations working behind the scenes to try and prevent issues like this. Unfortunately these sometimes fail.

The most likely cause IMHO is going to be driver related of some description, which unfortunately it is very hard to design out of the system.

-Leezer-
 
diamount said:
Guy was doing 44mph in a 12mph zone :mad:

http://www.bbc.co.uk/news/uk-england-38003934

No faults were found on the tracks or the tram itself.
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Also in that link, a choice quote from the train drivers union.

Aslef, the train drivers' union, said it was "clear that the lack of adequate safety systems were at the root of this dreadful accident".
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It takes the **** that they're trying to escalate this to cover a drivers back, months before the investigation is completed. Don't they have any respect or decency?
 
So a vehicle which basically steers itself on a set route and the driver only has to do a couple of things needs more safety systems? We might as well shut down all motorways right now where people have full control of their vehicles, working or otherwise.

Backwards union ****s.
 
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