Rubber wheels trains

[zaax]

Living above a railway line for a week in Dawlish I have noticed that some trains are a lot quieter in passing than others and looking at their wheels some of them seem to be black which seems to be rubber rather than a shiny Steel of the local trains which are quite noisy.

Am I correct in saying HST trains have rubber wheels?

 

[AlterEgo]

Am I correct in saying HST trains have rubber wheels?

No.

 

[DasLunatic]

Am I correct in saying HST trains have rubber wheels?

You're not. Rubber-wheeled trains are almost entirely on metro services, such as in Paris. Last time I checked, the Dawlish sea wall is not on a metro service, nor is it in France.

 

[tsr]

You're not. Rubber-wheeled trains are almost entirely on metro services, such as in Paris. Last time I checked, the Dawlish sea wall is not on a metro service, nor is it in France.

The sea does, however, like to make donations of large pieces of sea wall to France on a semi-regular basis.

 

[Domh245]

Train wheels are all steel, it's part of what makes rail so efficient, the coefficient of friction for steel on steel is low so the trains can coast for long distances. I think that you might be seeing the brake disks which is what might be confusing you. On local trains (but more noticable on these trains) the brake disk is set into the wheel, with the brake pad situated at the inboard edge. This is the same for the local stock, except the bogie frame is located covering most of the wheel. As far as I can tell, the HSTs have a similar system, although the frame is much bulkier, obscuring more of the wheel.

 

[47271]

Ignore those who take the mick on here. Your question is unusual but not unreasonable.

You're probably getting the impression that the HSTs are quieter because they don't have underfloor engines, I can't think of any other reason.

 

[Philip Phlopp]

Train wheels are all steel, it's part of what makes rail so efficient, the coefficient of friction for steel on steel is low so the trains can coast for long distances. I think that you might be seeing the brake disks which is what might be confusing you. On local trains (but more noticable on these trains) the brake disk is set into the wheel, with the brake pad situated at the inboard edge. This is the same for the local stock, except the bogie frame is located covering most of the wheel. As far as I can tell, the HSTs have a similar system, although the frame is much bulkier, obscuring more of the wheel.

I don't think any local stock on the Dawlish line will have disk brakes of that type, they'll all be tread brake, with the exception of the Class 158 which has inboard axle mounted disks, so externally the wheelsets look the same.

The only wheel face mounted disk braked stock on the route will be HST and Voyager fleets.

 

[me123]

I'm a bit disappointed that someone who's probably not very knowledgable about railways asks an honest question (albeit a relatively easy one that most of us can answer) and is ridiculed by some. It's a perfectly reasonable question, and the OP should have been able to ask it without being ridiculed.

Zaax, as has been said, all UK trains have steel wheels. Trains with rubber tyres do exist elsewhere - Paris is the most commonly used example (and, truth be told, the only one I could come up with). As you can see here, the wheels look very different to what we're used to seeing in the UK.

 

[scott118]

All UK trains have steel wheels. Around these wheels is a steel tyre. Should a wheelset pick up and result in a set of 'flats', then it is the tyre that is re-profiled on a wheel lathe, to eliminate the flat spot, and get the wheelset back into service. Tyres are obviously cheaper, than a complete wheelset to profile or even replace.

Should the radius of a curve, be too tight for a live axle, then an automatic greaser will be attached to the rail, to eliminate the squeal, that is created between the wheel flange and the side of the railhead. This is operated by the passage of the train. It will also be, noticeably quieter, when you have rainfall or a damp period of the day.

Perhaps the difference you are hearing, is, simply, in the train weight.

 

[WarrenTManager]

Ignore those who take the mick on here. Your question is unusual but not unreasonable.

You're probably getting the impression that the HSTs are quieter because they don't have underfloor engines, I can't think of any other reason.

Class 86 sub classes /2/3/4 have SAB resilient wheels. These are steel and rubber, the rubber acting as a cushion for the wheel where pairs of rubber blocks were compressed between the outer, middle and inner wheel centre discs. It was a Swedish firms design and taking the initials of the firm in terms of the SAB bit.......

Although 86's don't go near Dawlish I think it's a good question.

 

[najaB]

It's a perfectly reasonable question, and the OP should have been able to ask it without being ridiculed.

Did some posts get deleted? I don't see much in the way of ridicule.

 

[me123]

^At least one has, certainly the post I was directly referencing is no longer there.

 

[100andthirty]

The noise you hear is the wheel rolling on the rails. Train with tread brakes (friction material rubs along the tread of the wheels leads to the wheels being rougher than they are with disc brakes. The roughness is not really visible to the naked eye. It is clearly audible if trains with mixed mk2 (tread brakes) and mk3 (disc brakes) carriages pass - eg the sleeper trains. Mk2 carriages are much more noisy. You might also be hearing some squeal from Pacer type vehicles which have only 4 wheels per carriage. These make quite a din as they "fight the track" going round curves.

 

[Darandio]

Did some posts get deleted? I don't see much in the way of ridicule.

The DasLunatic reply was a bit close, a simple 'no' was sufficient, not some lecture on how Dawlish isn't in France.

 

[Mordac]

I'm a bit disappointed that someone who's probably not very knowledgable about railways asks an honest question (albeit a relatively easy one that most of us can answer) and is ridiculed by some. It's a perfectly reasonable question, and the OP should have been able to ask it without being ridiculed.

Zaax, as has been said, all UK trains have steel wheels. Trains with rubber tyres do exist elsewhere - Paris is the most commonly used example (and, truth be told, the only one I could come up with). As you can see here, the wheels look very different to what we're used to seeing in the UK.

Montreal Metro as well, but that system is heavily inspired by the Paris one.

 

[Harbornite]

I should add that cars don't usually have rubber wheels, they have rubber tires/ tyres but I am being pedantic. Trains also have tires/ tyres, but made from steel rather than rubber in almost all cases.

 

[trainmania100]

Rubber wheels would probably come in handy on icy rails and during RHTT season

(Then again, my hornby ring field hst with traction tyres is useless on oily slipery track)

 

[DaleCooper]

Train wheels are all steel, it's part of what makes rail so efficient, the coefficient of friction for steel on steel is low so the trains can coast for long distances.

I'm not sure about this but isn't it the rolling resistance, which is lower for steel tyres versus rubber, which is most important?

 

[najaB]

I'm not sure about this but isn't it the rolling resistance, which is lower for steel tyres versus rubber, which is most important?

It is, indeed. Largely because the contact patch is so tiny. The actual CoF (which is more about resistance to sliding) is quite high, otherwise trains wouldn't be able to stop.

 

[DaleCooper]

It is, indeed. Largely because the contact patch is so tiny. The actual CoF (which is more about resistance to syliding) is quite high, otherwise trains wouldn't be able to stop.

Also the hysteresis loss of rubber is much greater than steel which means more energy is lost in deformation of the tyre.

 

[CosherB]

You're not. Rubber-wheeled trains are almost entirely on metro services, such as in Paris. Last time I checked, the Dawlish sea wall is not on a metro service, nor is it in France.

Thanks for making a new member feel so welcome. Small wonder the fraternity has such a reputation. :roll:

 

[lincolnshire]

Trains do have rubber wheels.!

I have at least two with rubber tyres on them the only snag is that they are diesel loco,s and they was made by Hornby Dublo ( 3rd rail actually) and are on a model railway.

 

[Taunton]

Resilient wheels, with a thin rubber ring and steel both sides, as on the 86/2, have been around for a long time, and are particularly common on tramcars. I can't think they are fitted to anything passing Dawlish. They reduce noise but also aid the suspension and minimise unstrung weight/hammer blow of the rail vehicle. Wheels that look black have likely been painted so. Steam locomotives used a range of colours to paint their wheels over time, to go with the overall livery.

Paris Metro-style fully rubber tyred trains require notably complex both rolling stock and track, and have much poorer energy efficiency. They gave better performance than what was available on normal rails when first introduced in the 1950s (particularly on a network like Paris with very short distances between stops), but not nowadays, steel wheels/rail has caught up. They also make Metro stations on such lines smell like an old tyre depot.

 

[edwin_m]

Also the hysteresis loss of rubber is much greater than steel which means more energy is lost in deformation of the tyre.

That's effectively the reason for the greater rolling resistance, not something that happens as well.
--- old post above --- --- new post below ---

It is, indeed. Largely because the contact patch is so tiny. The actual CoF (which is more about resistance to sliding) is quite high, otherwise trains wouldn't be able to stop.

A vehicle with all wheels braked can in theory achieve a maximum deceleration (expressed as a percentage of the acceleration of gravity, g) the same as the coefficient of friction between the wheel and the rail. In practice brakes will usually work at a lower deceleration than typical CoF, because it is better not to lock the wheels and slide. The CoF of steel on steel is usually around 15-20% and modern passenger trains brake at 9-12%g. In very poor adhesion conditions it can fall to around 2% and a train braking will be in big trouble unless it is also able to dispense sand, which improves the friction significantly.

Trams with track brakes can achieve around 25%g, even though the track brake is also steel on steel. This is possible because the track brake is magnetised onto the track, and this magnetic force multiplied by the coefficient of friction provides an extra decelerating force.

The coefficient of friction of rubber on steel is higher, at least in the dry, and for rubber on road surfaces it can be around 50%. So rubber wheel trains as well as road vehicles are able to decelerate at much greater rates than steel wheel trains without track brakes. However, as is being discussed in another thread, brake rates above about 15% aren't really tolerable for standing passengers.

The same applies in reverse to acceleration, but only if all axles are motored which on trains they usually aren't, so acceleration at low speeds reduces in proportion to the amount of weight resting on motored axles. At higher speeds it is further limited by the available power.

 

[TRAX]

Montreal Metro as well, but that system is heavily inspired by the Paris one.

Also South America, again inspired by the Paris ones.

 

[notadriver]

I'm a bit disappointed that someone who's probably not very knowledgable about railways asks an honest question (albeit a relatively easy one that most of us can answer) and is ridiculed by some. It's a perfectly reasonable question, and the OP should have been able to ask it without being ridiculed.

Zaax, as has been said, all UK trains have steel wheels. Trains with rubber tyres do exist elsewhere - Paris is the most commonly used example (and, truth be told, the only one I could come up with). As you can see here, the wheels look very different to what we're used to seeing in the UK.

That's a nice pic. Those won't be around much longer [emoji22][emoji22]


Sent from my iPhone using Tapatalk

 

[snowball]

It is, indeed. Largely because the contact patch is so tiny. The actual CoF (which is more about resistance to sliding) is quite high, otherwise trains wouldn't be able to stop.

Or accelerate (except downhill).

 

[furnessvale]

I'm a bit disappointed that someone who's probably not very knowledgable about railways asks an honest question (albeit a relatively easy one that most of us can answer) and is ridiculed by some. It's a perfectly reasonable question, and the OP should have been able to ask it without being ridiculed.

Zaax, as has been said, all UK trains have steel wheels. Trains with rubber tyres do exist elsewhere - Paris is the most commonly used example (and, truth be told, the only one I could come up with). As you can see here, the wheels look very different to what we're used to seeing in the UK.

We must not forget what an absolute nightmare rubber tyres are in a tunnel or underground situation.

London Transport has problems now dissipating the heat from tunnels. The extra heat from tyres are a problem for Paris which, IMO, is an easier location than our underground to ventilate.

 

[Taunton]

Rubber tyred-Metros also exist in French provincial cities. Lille, Lyon, Rennes and Toulouse have them, all built relatively recently. The system, designed originally by Michelin, is seen as something of a French icon.

 

[Beebman]

The Yurikamome Line in Tokyo also has rubber tyres.

http://www.yurikamome.tokyo/mechanism/characteristic/