Wet, narrow tyres, angle.
Such a dangerous layout too.
http://www.edinburghnews.scotsman.com/news/cyclist-helmet-cam-video-of-tram-track-crash-1-3516685
What a lot of nice people helping him!
CityCyclingEdinburgh Forum » General Edinburgh
"Cyclist helmet cam video of tram track crash"
(29 posts)-
Posted 9 years ago #
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God that's scary. I have to do that exact same manoeuvre when I cycle home from work although I try to keep to the inside lane and 'hop' over the tracks at a greater angle.
still will make me think a bit more about crossing them!
Posted 9 years ago # -
Never read the comments... :-/
Posted 9 years ago # -
"Never read the comments"
I decided not to look!
Posted 9 years ago # -
Plenty of evidence on here to support this route through the tracks - kaputnik's excellent video I think also shows this line. I take this line every time, but try to achieve an even greater angle. The problem is that you have to shoulder check just before doing both sets of tracks, and I've been undertaken after crossing the first set on numerous occasions which takes your concentration away from doing the second set… it is truly lethal…. I hope this guy is not too badly hurt - it looked a nasty fall.
Posted 9 years ago # -
@algo - do you have a link to kaputnik's video? just trying to educate myself on the best route through there! :-)
Posted 9 years ago # -
This is it (hope it's ok to post again) - some changes at Haymarket since this video was made I think, but it's really good at showing why you have lots to think about even before you cross the lines!
Posted 9 years ago # -
thanks
Posted 9 years ago # -
"hope it's ok to post again"
Of course - especially as I haven't seen it before!
Where did the pink bike go?
Posted 9 years ago # -
"I was cycling at the optimal angle to cross those tracks"
It's the EEN so probably a misquote but that certainly didn't look like a 90 degree crossing to me.
He also wasn't particularly lucky that there wasn't a tram coming the other way. If there had been then the light would have remained at red.
Posted 9 years ago # -
Hmm. Wasn't a great angle to cross at really. Hope he's ok tho.
Posted 9 years ago # -
Two weeks ago I crashed on Princes St when my front wheel got stuck in the tram lines. I was overtaking a stopped bus and I flew over the bar at 25 km/h. I got a nasty bruise now as a reminder.
I didn't want to believe myself when Spokes says that can happen also the experienced people. I always make sure I cross at wide angle, checked the videos, tested my bike on the tracks to make sure if it could get stuck.
I didn't remember that I changed the tyres the week before and these new tyres are slightly thinner that the ones I tested.
Posted 9 years ago # -
Currently my fast PC is playing up but look closely at 1.24 and 1.42 (and elsewhere)there seems to be a distinct loss of the infilling material (or hollow spots) on the outside edge of the rails.
Difficult to tell from the video without the ability to take it down to a frame-by-frame sequence, but I think that the rider crossed both the railheads without any problems, and the tyre caught the slot OUTSIDE the 4-foot - ie outside the rails - where the tarmac has either crumbled away (as it was doing at the foot of The Mound when I last looked closely)or the poured 'seal' has been dragged out by heavy vehicles (as photographed example by The Mound (Arellcat & I have pictures))
Can someone in Edinburgh get some photos (safely) of the condition of the road surfaces as they abut the rails at this point. May directly send to a couple of list members
Posted 9 years ago # -
@Tulyar I may go down there later this evening (i.e. outside rush hour) on the way to the pub & might be able to get some photos. I take it that it is the fall video you are refering to and not kaputniks?
Posted 9 years ago # -
Certainly was not an optimal angle for going across the tracks, looked (to my untrained eye) to be about a 30 degreee angle when I would expect to cross the trams at min a 45 degrees.
Posted 9 years ago # -
+1 Zesty
Having come down on the tracks myself in similar conditions of wet, slippy tracks, at the bottom of Lothian Road, it's even more imperative to cross at as large an angle as possible. 30 degrees won't cut it (though in the dry you'll likely get away with it).
Posted 9 years ago # -
it's even more imperative to cross at as large an angle as possible.
All good advice (the same as given out by the council), but at Haymarket it is pretty near impossible, when the angle of travel (as determined by the road markings and presence of other vehicles) crosses the tracks at something between 10 and 20 degrees.
It's simply not acceptable to have the council/trams handing out advice about crossing the tracks at as close to 90 degrees as possible and not under an angle of 60 degrees and then to build a road/rails layout with such acute angles between the path of the rails and the direction of road traffic. The same is true at the foot of the Mound. If you follow the painted markings on the road, you don't come near to crossing the tracks at a safe angle.
Posted 9 years ago # -
In my opinion this is all the fault of the infrastructure - I've nearly come a cropper there a few times despite knowing the advice and thinking carefully about how best to do it.... also with video analysis such as kaputnik's and wingpig's here:
http://citycyclingedinburgh.info/bbpress/topic.php?id=11324&page=4
Posted 9 years ago # -
30 degrees won't cut it (though in the dry you'll likely get away with it)
And you have to have completed your turn to the correct angle before you cross the rails, especially in wet weather.
Posted 9 years ago # -
@fimmIt was the falling down video I was looking at hence the time points. I've ridden over tracks in many cities and the quality of flatness plays a major role in delivering a safe crossing of the rails. Edinburgh's contractor has not delivered quality anywhere close to that seen in other UK cities. Why this is so - I have no idea.
Posted 9 years ago # -
@Cyclingmollie A correct point, the contact patch for a typical 700c tyre is around 120mm long, and will obviously 'bridge' a slippery strip of road if crossed at an angle close to 90 degrees.
For this reason - especially for motorbikes and repaired road openings on corners the tar banding seal for road repairs has a maximum width of 50mm. This should mean that a cornering 2-wheeled vehicle (and 4 wheeled ones to a lesser degree) will have some of the contact patch on a high friction area.
The performance is reduced when the slippery area - namely the railhead, or frame of street ironwork, sits proud of the tarmac, sufficient to lift the tyre and reduce the friction available from the high friction surfaces - hence the limits for street ironwork (sic) of 3mm above the tarmac .... well that's the theoretical standard which is supposed to apply.
Combine side thrust through crossing a slippery strip when making a turn and a vertical disparity which can both remove the tyre from the high friction surface AND deflect the tyre (any step of over 6mm can deliver a rotational force pivoting around the upper edge of the vertical 'step' This can be viewed as a sum of forces in the 3 planes - vertically a small element of lifting and thus reducing the friction the tyre provides to resist the lateral force which has the biggest component rotating the bike and rider around the pivot point of the upper edge and a small logitudinal force, which may turn the front wheel and enhances the 'rotation' (or force which brings down the bike & rider)
It should be possible to ride over rail lines at an angle well under 60 degrees with some clear provisos.
1) the vehicle (2 or 4 wheeled) should not be turning - it should be rolling in a straight line, with no sideways forces.
2)the surfaces of the abutting elements should be as flat as possible, to ensure that tyre contact is maintained, and no sideways forces are delivered by the tyre(s) striking a ridge.
The trams network in Sheffield monitors their rail-road profiles rigorously, with a 3mm limit, as a result of a substantial claim paid out to a car driver who suffered life changing injuries, when, it was claimed, the tyres of his car were raised clear of the road surface by the rails, and he crashed. If Edinburgh's tracks remain with such large vertical disparities, it may only be a matter of time before a car driver loses control crossing them.
Posted 9 years ago # -
Tulyar, while that may all be true, as a driver also, I can state that many of the roads are in such a poor state of disrepair that a larger than 3mm difference at the tracks will not be noticed by a car driver.
Frankly, the tram route has one of the best surfaces - for cars.
To me, CEC must look at using one of these rubber 'infill' solutions - at least in areas (Haymarket, mound, st A square turn) where angles are poor for cyclists/motorbikes.
Posted 9 years ago # -
@Tulyar I didn't go out in the end so I don't have photos I'm afraid. I did have a look as I came out of Haymarket at rush hour but couldn't see much that was obvious. I'll try and get some photos at some point.
Posted 9 years ago # -
I'll try and pop over at lunchtime, when it ought to be quieter than on the way in or home.
Posted 9 years ago # -
It looked an overly aggressive manoeuvre to me given the weather & road conditions.
Posted 9 years ago # -
@tulyar I tried on my way past earlier at lunch time to take some pictures of the tracks hopefully showing the road surface as it abuts - I hope it's of some… you can use right click to open the image in a new tab and they are reasonably zoomable...
Posted 9 years ago # -
I think I've worked out the problem with traction. This road seems to be on the ceiling.
Posted 9 years ago # -
@dougal - well spotted. I have now attempted to allow for the peculiar gravitational effects at Haymarket and rotated the pictures in the preview. The big versions are now all upside down…..
Posted 9 years ago # -
Posted 9 years ago #
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