accident at sandilands

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palkanetoijala31

accident at sandilands

Post by palkanetoijala31 » 09 Nov 2016, 19:53

a heartfelt tragedy always thought that bend would cause an accident

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Re: accident at sandilands

Post by DavidC » 09 Nov 2016, 22:17

Very sad news - I'm sure all our thoughts are with the families and friends of those killed and with the injured. One of my friends commutes on that stretch of line but thankfully wasn't on that service. Also, soberingly, I caught that unit three times during my recent pair of Challenge completions, including over the section from New Addington to Sandilands. May I suggest that discussion of causes is for another time and that for now we focus on expressions of sympathy. DavidC.
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Re: accident at sandilands

Post by Tube Geek » 10 Nov 2016, 15:00

DavidC wrote:Very sad news - I'm sure all our thoughts are with the families and friends of those killed and with the injured. One of my friends commutes on that stretch of line but thankfully wasn't on that service. Also, soberingly, I caught that unit three times during my recent pair of Challenge completions, including over the section from New Addington to Sandilands. May I suggest that discussion of causes is for another time and that for now we focus on expressions of sympathy. DavidC.
I agree, causes shouldn't be discussed considering...

And my sympathy goes out too, i think (from memory) that is the only tram i've seen in flesh!
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Re: accident at sandilands

Post by GuyBarry » 16 Nov 2016, 16:08

Just heard on the BBC that the tram was travelling at more than three times the speed limit:

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

Absolutely no idea why. The driver had reduced his speed from 50mph to 43.5mph in a 12mph zone.
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Re: accident at sandilands

Post by The Orange One » 17 Nov 2016, 14:10

Well, there's your cause - trying to take that bend at 43 miles an hour? What the hell?
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Re: accident at sandilands

Post by GuyBarry » 17 Nov 2016, 18:15

The Orange One wrote:Well, there's your cause - trying to take that bend at 43 miles an hour? What the hell?
I meant I had no idea why the driver was travelling that fast.
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Re: accident at sandilands

Post by Tube Geek » 21 Nov 2016, 17:35

Personal Best - 264 Stations in 19 hours 37 minutes. I hate the Piccadilly line.... :evil:
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Re: accident at sandilands

Post by RobbieM » 21 Nov 2016, 20:32

Might I suggest that, if there were black-and-white chevrons on this bend (like we have on the roads), the risk of accidents such as this happening could be reduced?

Let me explain. The tram lines each side of these junction travel along an old railway track, and as such, the ‘visual cues’ probably suggest that it is still a straight track ahead. Someone travelling through the tunnel may know intellectually that there’s a sharp bend just after they emerge. But if their eyes tell them differently, any small distraction may cause the visual cues to take precedence. (I’m not saying that’s what actually happened on this occasion, merely that it could be a significant risk factor.)

I have a particular reason for thinking this. I live about a mile from the ‘Hog’s Back’ junction between the A3 and A31 in Guildford. See this link (but ignore the sharp right turn at the right of the picture). Most traffic travelling along the A31 towards Guildford heads straight ahead to join the A3 towards London. But there’s a filter lane on the right which allows traffic to head into central Guildford. However, as you’re ‘getting into lane’ before the junction, the visual cues suggest that this lane also goes straight ahead. These cues are mainly high trees, which are usually all you can see above the car in front. This car blocks your view of what the road actually does. (Zoom out on the picture to get a better idea.)

You may be able to work out that this sudden shift to the right often takes drivers by surprise, and you’d be right. But before 15/20 years ago (when the junction was straightened out a little) the effect was far more pronounced. Especially when travelling at 60mph. And no matter how many times I used to drive it, and I knew the road suddenly shifted, it still used to freak me out. And I guess I was just one of hundreds of regular users of the junction. But the visual cues were SO strong, they continued to betray the true nature of where the road goes.

So at Sandilands, if a driver travelling through the tunnel could see chevrons in the distance ahead (across the apparent course of the track), perhaps there’d be an extra psychological incentive to over-ride the visual cues, and slow down sooner for the bend?

For discussion.
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Re: accident at sandilands

Post by Tube Geek » 21 Nov 2016, 22:03

That wouldn't stop him going 43 mph though
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Re: accident at sandilands

Post by The Orange One » 22 Nov 2016, 12:07

Tube Geek wrote:That wouldn't stop him going 43 mph though
It would remind him to slow down earlier!
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Re: accident at sandilands

Post by RobbieM » 22 Nov 2016, 21:44

The Orange One wrote:It would remind him to slow down earlier!
Exactly. It’s the fact that visual cues are more powerful than intellectual cues.

On the roads, there are different reasons why people end up speeding. One may do so recklessly, with no regard for the limits put in place. Another may do so unwittingly, because it’s so easy to speed up if you can see a clear road ahead of you. They don’t intend to speed, but just end up doing so. However, both of these drivers are highly likely to put the brakes on if they can see they are approaching an imminent hazard. (The visual cues ensure this!)

(Similarly, on the trains: ATP systems shouldn’t be needed in an ideal world. But their existence recognises the fact that humans are prone to error/distraction. It’s an extra safety feature, which is very welcome indeed.)

My concern for track layouts like that at Sandilands is that there appear to be few (if any) visual cues of a hazard up ahead. The eyes probably tell a driver that the track continues into the distance. So if, for whatever reason, he or she fails to observe the speed restrictions, there may be a far greater chance of an incident taking place.

But the chevrons I suggested above would lie directly across the apparent course of the track, giving the necessary visual cue to slow down much sooner.
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Re: accident at sandilands

Post by RobbieM » 20 Feb 2017, 15:19

At last. Read the final paragraph of this...

http://www.bbc.co.uk/news/uk-england-london-39027670

...and it shows that the RAIB have been thinking along the same lines as myself. I'm sure it will help prevent future accidents.
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Re: accident at sandilands

Post by greatkingrat » 20 Feb 2017, 18:08

Although they also say the trams should start braking at the entrance to the tunnel. So by the time they exit the tunnel and see the chevrons it may be too late anyway.
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Re: accident at sandilands

Post by RobbieM » 20 Feb 2017, 22:02

Though hopefully the chevrons should be visible a long way back in the tunnel - it's so straight! The second picture in this article gives an idea of how far they should be seen down the tunnel. It should help, to some extent at least, with the 'visual cues'.
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