Rubber wheels trains

[edwin_m]

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.

Many of these use the VAL system, which is simpler than the rubber-tyre Metro technology but probably developed from it. VAL trains do not need auxiliary steel wheels and run on a concrete guideway instead of steel strips, which also improves the coefficient of friction.

https://en.wikipedia.org/wiki/Véhicule_Automatique_Léger

 

[Cliveblackpool]

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.

One of those types of wheel design was involved in a horrific railway accident in Germany - one of the worst ever. https://en.wikipedia.org/wiki/Eschede_derailment

 

[notadriver]

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.

I'm not sure I agree the rubber tyre technology is completely outmoded as line 14 in Paris could have been designed with conventional steel rails. Modern rubber tyred MP89 stock accelerates at 1.3 m/s per second. The MF2000 or MF01 accelerates at 0.9 m/ per second. I know the S stock has been quoted to accelerate at 1.3m/s per second but this hasn't yet been achieved in service.


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[jamesontheroad]

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

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.

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.

I was in Montréal last month, and unexpectedly got to ride one of the brand new Bombardier-Alstom MPM-10, which are the first new trains to be ordered for the métro since the 1970s.

The rubber tyre system was cutting edge at the time, but Montréal's politicians did well to refuse a completely French designed system of trains, track and signalling. They insisted instead on designing and building the trains in Québec. This book is excellent on the history.

At the time - with cheap rubber - it was very cost effective. Generally (although not everywhere in the city) the stations were built using cut-and-cover trenches near the surface, with the tunnels often dipping down deeper between stops. This allowed trains to use gravity to build speed on the departure and slow down on arrival.

Unlike many subway systems in North America (including Toronto and Chicago), Montréal's system is entirely underground, meaning the seriously sub-zero winters and heavy snow fall didn't make tyres impractical.

 

[yorksrob]

Also South America, again inspired by the Paris ones.

Yes, I remember being intrigued by the concrete rails and rubber tyres when travelling on the Mexico City system.

I gather the "bang" when one of them bursts underground can be quite alarming !

 

[TRAX]

Heat from the tyres in the Paris Metro isn't considered a problem. The heat difference compared to steel systems is barely inexistant, in fact.



Tyres on the Paris Metro basically never burst. There is basically only a 1 % chance of this happening.

 

[DaleCooper]

Heat from the tyres in the Paris Metro isn't considered a problem. The heat difference compared to steel systems is barely inexistant, in fact.



Tyres on the Paris Metro basically never burst. There is basically only a 1 % chance of this happening.

I'd hardly call a 1% chance "basically never burst", that actually sounds like a serious problem.

 

[edwin_m]

I'm not sure I agree the rubber tyre technology is completely outmoded as line 14 in Paris could have been designed with conventional steel rails. Modern rubber tyred MP89 stock accelerates at 1.3 m/s per second. The MF2000 or MF01 accelerates at 0.9 m/ per second. I know the S stock has been quoted to accelerate at 1.3m/s per second but this hasn't yet been achieved in service.

The rubber tyre routes of the Paris Metro have notices inside the trains warning people to hold on because of the severe braking. I think this demonstrates how 1.3m/s/s is actually at about the limit for passenger comfort.

 

[furnessvale]

Heat from the tyres in the Paris Metro isn't considered a problem. The heat difference compared to steel systems is barely inexistant, in fact.


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Without wasting my time doing other research, Wiki disagrees.

 

[edwin_m]

I'd hardly call a 1% chance "basically never burst", that actually sounds like a serious problem.

It is a totally meaningless statement without some qualification about how many tyres it applies to over how long a period. But it's obviously serious enough that the Metro keeps a full set of steel rails and the trains carry steel wheels around, which are only used on turnouts and in the event of a tyre burst. However the newer but smaller-scale VAL systems dispense with this.

 

[jopsuk]

Heat from the tyres in the Paris Metro isn't considered a problem. The heat difference compared to steel systems is barely inexistant, in fact.



Tyres on the Paris Metro basically never burst. There is basically only a 1 % chance of this happening.

1% over what time frame because that seems horrifying if it's daily. Including the smaller side contact ones there's eight per bogie. That's 16 per carriage. 96 per train. 1% punctures per day would be an average of a burst tyre on almost every train every day

 

[DaleCooper]

Without wasting my time doing other research, Wiki disagrees.

I think you're right, it's well known that rubber tyres get hot due to hysteresis loss; it's the dissipation of energy through heating that gives rubber tyres an advantage on rough suirfaces by attentuating the transmission of shock and vibration. That's also why rubber is used in anti-vibration mounts for engines.

 

[TRAX]

It is a totally meaningless statement without some qualification about how many tyres it applies to over how long a period. But it's obviously serious enough that the Metro keeps a full set of steel rails and the trains carry steel wheels around, which are only used on turnouts and in the event of a tyre burst. However the newer but smaller-scale VAL systems dispense with this.

The main reason for the steel rails (which as a result have longer flanges) is for points. VAL systems don't have that because they have another system in the centre of the track to guide the trains (which don't have bogies but just single axles).

As for the 1 % probability, that would be per year. Oh and by the way I'm a Parisian...

And there are only four horizontal flanges per bogie.



And the "powerful braking" signs are also present in the MI 2N and MI 09 suburban EMUs which have standard steel wheels.

 

[SouthStand]

One of those types of wheel design was involved in a horrific railway accident in Germany - one of the worst ever. https://en.wikipedia.org/wiki/Eschede_derailment

Can't believe they didn't stop the train immediately after discovering the tyre embedded in the floor of the coach! WTF.

 

[najaB]

Can't believe they didn't stop the train immediately after discovering the tyre embedded in the floor of the coach! WTF.

Those were the rules at the time, I'm pretty sure they've changed now.

 

[Taunton]

The Paris Metro steel rails (standard gauge) inside the tyre trackways (which can be concrete, steel, or wire grids; all are in use in different places) serve multiple purposes. Apart from guiding through points and handling the VERY RARE punctures, they carry the conventional track circuits, activated not by the steel wheels, normally just clear, but by skids which slide along them - this is why the rails are so shiny. It also allows mixed running during the conversion process, which always takes several years, and allows standard PW vehicles to run along the line. This latter is a worthwhile point - whoever designed the BART in San Francisco thinking a broad 5'6" gauge was a good idea caused all sorts of later issues because the system is unable to lease in various specialist PW vehicles from the open market because they are an incompatible gauge.

The outer guide rails on the Paris Metro which contain the horizontal rubber wheels are steel, because these are also the conductor rails which convey the traction current to the train through horizontally-mounted sprung collector shoes.

 

[notadriver]

And the "powerful braking" signs are also present in the MI 2N and MI 09 suburban EMUs which have standard steel wheels.

They do have enhanced braking systems as I understand it - but their acceleration doesn't match rubber tyred metro stock. SACEM is still being used I assume prior to ATO being installed on the core route section of RER A and as If I understand the system correctly it is this that can apply the brakes sharply.




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[TRAX]

Taunton you are absolutely right. Notadriver that's right, although the ATO that is now being tested in fact uses the SACEM as a base.

The SACEM/ATO can of course make an EB application, but that will not be more powerful than when a driver does it.

 

[zaax]

Thank for your replies. The reason I asked was the part of the wheel touching the flat of the rail on HST looked dark, yet the flange looked nice and shiny, as did the whole wheel of the local train.

 

[randyrippley]

One of those types of wheel design was involved in a horrific railway accident in Germany - one of the worst ever. https://en.wikipedia.org/wiki/Eschede_derailment

On one website I noticed a reference to another crash - can't remember where -caused by these types of wheels. In this case the problem was due to too much material being ground off during wheel reprofiling, leaving the steel rim/tyre too flexible to resist stress and able to disengage from the wheel core. Not a fatigue crack as such, more a physical separation of the wheel components.