Winter is coming. 3mm is nothing on wet leaf covered and potentially snow covered roads.
My understanding is that tread-depth is positively related to clearing standing water from the contact patch to avoid aquaplaning.
I'd doubt it would have much positive influence on wet leaf covering, mostly because I can't think of a way it could, but also because a quick search of data sources didn't find anything on the effect of leaves, though it may be out there somewhere.
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Winter is coming. 3mm is nothing on wet leaf covered and potentially snow covered roads.
My understanding is that tread-depth is positively related to clearing standing water from the contact patch to avoid aquaplaning.
I'd doubt it would have much positive influence on wet leaf covering, mostly because I can't think of a way it could, but also because a quick search of data sources didn't find anything on the effect of leaves, though it may be out there somewhere.
Leaves on the rails are a regular excuse for cancelled/delayed trains here (in the country that invented railways).
There are special trains with high pressure water jetting equipment to blast the rail heads, apparently leaves form a film when crushed which adheres and causes wheel slip.
Current trains seldom have the adhesion weight per axle of steam locos and wheel sizes are not as large.
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Winter is coming. 3mm is nothing on wet leaf covered and potentially snow covered roads.
My understanding is that tread-depth is positively related to clearing standing water from the contact patch to avoid aquaplaning.
I'd doubt it would have much positive influence on wet leaf covering, mostly because I can't think of a way it could, but also because a quick search of data sources didn't find anything on the effect of leaves, though it may be out there somewhere.
Leaves on the rails are a regular excuse for cancelled/delayed trains here (in the country that invented railways).
There are special trains with high pressure water jetting equipment to blast the rail heads, apparently leaves form a film when crushed which adheres and causes wheel slip.
Current trains seldom have the adhesion weight per axle of steam locos and wheel sizes are not as large.
And train wheels are COMPLETELY BALD!
The HORROR!
I suppose oversteer isn't much of a problem though.
Edited by edlithgow on 27/09/2024 at 12:11
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Pirelli rather ungrammatically state
"The deeper the tread depth on your tyres, the better the performance on ice compared to a more worn tyres"
but then they would, wouldn't they?
Be more convincing if they said how/why.
I'd guess ice is pretty analogous to wet leaf film. Snow seems likely to be a bit more complicated
www.pirelli.com/tyres/en-gb/car/driving-and-tyre-t...e
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<< Leaves on the rails are a regular excuse for cancelled/delayed trains here (in the country that invented railways). >>
I don't think much useful parallel can be drawn between flexible tyres on tarmac roads with leaf cover, and steel wheels on steel rails. Do you ? If so, what ?
Nor do I think that tread depth will make a lot of difference if wet leaf cover is enough to pose a severe skidding hazard. In fact I might imagine that shallow tread, being more rigid, could be slightly more help than 7 or 8mm depth ?
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<< Leaves on the rails are a regular excuse for cancelled/delayed trains here (in the country that invented railways). >>
I don't think much useful parallel can be drawn between flexible tyres on tarmac roads with leaf cover, and steel wheels on steel rails. Do you ? If so, what ?
Nor do I think that tread depth will make a lot of difference if wet leaf cover is enough to pose a severe skidding hazard. In fact I might imagine that shallow tread, being more rigid, could be slightly more help than 7 or 8mm depth ?
The common factor is that wet leaves are slippery and difficult for a wheel to cut through to grip on the underlying surface.
It may be that higher wheel loading/wheel size means that HGVs are less affected than cars, I have not seen comparison data to confirm or deny this speculation.
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<< Leaves on the rails are a regular excuse for cancelled/delayed trains here (in the country that invented railways). >>
I don't think much useful parallel can be drawn between flexible tyres on tarmac roads with leaf cover, and steel wheels on steel rails. Do you ? If so, what ?
Nor do I think that tread depth will make a lot of difference if wet leaf cover is enough to pose a severe skidding hazard. In fact I might imagine that shallow tread, being more rigid, could be slightly more help than 7 or 8mm depth ?
I might imagine that NO tread, giving more contact area, could be slightly more help, as it is on a dry clean road surface, though I dont know this for a fact, and it wouldn't be of any practical use in the UK even if it were true
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Winter is coming. 3mm is nothing on wet leaf covered and potentially snow covered roads.
My understanding is that tread-depth is positively related to clearing standing water from the contact patch to avoid aquaplaning.
I'd doubt it would have much positive influence on wet leaf covering, mostly because I can't think of a way it could, but also because a quick search of data sources didn't find anything on the effect of leaves, though it may be out there somewhere.
Leaves on the rails are a regular excuse for cancelled/delayed trains here (in the country that invented railways).
There are special trains with high pressure water jetting equipment to blast the rail heads, apparently leaves form a film when crushed which adheres and causes wheel slip.
Current trains seldom have the adhesion weight per axle of steam locos and wheel sizes are not as large.
The problem is not the weight of the individual carriages, it is that since the mid-70s trains have had disc brakes, like a car, whereas older trains had tread brakes. Here the cast iron brake blocks worked on the steel tyres of the wheel and had the effect of sc***ing off debris, but they are not as effective as disc brakes.
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<< The problem is not the weight of the individual carriages, it is that since the mid-70s trains have had disc brakes, like a car, whereas older trains had tread brakes. Here the cast iron brake blocks worked on the steel tyres of the wheel and had the effect of sc.raping off debris, but they are not as effective as disc brakes. >>
Yes indeed, but neither kind of brake does anything to help the steel wheel make direct contact with the rail, which is the only way to stop a train. Disc brakes will at least avoid being contaminated with leaves, while blocks don't.
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<< The problem is not the weight of the individual carriages, it is that since the mid-70s trains have had disc brakes, like a car, whereas older trains had tread brakes. Here the cast iron brake blocks worked on the steel tyres of the wheel and had the effect of sc.raping off debris, but they are not as effective as disc brakes. >>
Yes indeed, but neither kind of brake does anything to help the steel wheel make direct contact with the rail, which is the only way to stop a train. Disc brakes will at least avoid being contaminated with leaves, while blocks don't.
Also, the old trains had a facility to apply sand to the track before the driving wheels. I would have thought it would be sharp enough to pierce a layer of slimy leaves under the driving loco's weight.
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<< The problem is not the weight of the individual carriages, it is that since the mid-70s trains have had disc brakes, like a car, whereas older trains had tread brakes. Here the cast iron brake blocks worked on the steel tyres of the wheel and had the effect of sc.raping off debris, but they are not as effective as disc brakes. >>
Yes indeed, but neither kind of brake does anything to help the steel wheel make direct contact with the rail, which is the only way to stop a train. Disc brakes will at least avoid being contaminated with leaves, while blocks don't.
Also, the old trains had a facility to apply sand to the track before the driving wheels. I would have thought it would be sharp enough to pierce a layer of slimy leaves under the driving loco's weight.
Loco's certainly have sanding gear, not sure if multiple unit carriages do, obviously more complex to fit and refill than on a loco.
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<< .... the old trains had a facility to apply sand to the track before the driving wheels. I would have thought it would be sharp enough to pierce a layer of slimy leaves under the driving loco's weight. >>
I don't know about sand on modern trains, but those disc brakes are efficient enough to lock axles if applied with too much force, even without leaves on the line. That easily causes flats on the wheel(s) which can often be heard passing my house :-)
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