Tyres and brakes

[Daz28]

Forgive what might be a stupid question, but has anyone ever tried to design an engine or carriages with rubber tyres? Presumably if such a thing were possible, it would have great braking capability and good acceleration, but require replacements at an alarming frequency?

Have any trains supplemented their braking capability with a brake block that is in contact with the rails?

 

[AlexS]

Yes, they are in use on several Metro systems around the world.

 

[ert47]

There is Japan's Yurikamome line in Tokyo and I think one line on the Paris Metro is tyred (not completely sure on that though!

 

[BlythPower]

The Michelin Railcar. If you can get Travel Channel (Freesat 405) keep an eye out for a Floyd on Africa episode where Keith travels on one in Madagascar.

 

[John Webb]

......Have any trains supplemented their braking capability with a brake block that is in contact with the rails?

I'm not certain about trains, but trams ancient and modern have magnetic track brakes, primarily for emergency use. An electromagnet, with its bottom face lined with an appropriate medium, is suspended just above the track. When turned on, the magnetic force moves the magnet into contact with the rail supplementing the wheel/axle brakes.

 

[D365]

Would the Gatwick and Stansted (airside) Transits be examples of that originally described? I am not aware of the advantages and disadvantages to 'traditional' rail, aside from as I see it, greater manoeuvrability (can handle steeper gradients and tighter turns, despite being rather wide).

 

[edwin_m]

I believe some main line trains in the Netherlands also have track brakes.

German high speed trains (some of them at least) have what look like track brakes but are in fact eddy current brakes. A magnet sits just above the rail and induces electric currents within the rail itself, so that the energy of motion of the train is converted into heat in the rail.

About half the Paris Metro has rubber tyres IIRC, plus some metros in other countries particularly those using French technology. Although the rubber tyres give more grip on an underground route they are less successful on surface sections because friction between rubber and steel is pretty poor when wet. The VAL systems used in airports and elsewhere use a concrete track instead.

 

[D365]

The VAL systems used in airports and elsewhere use a concrete track instead.

So basically like a Guided Busway (?) but completely fixed, including power source. [...and more 'specialised'!]

 

[edwin_m]

A little bit like that, though they probably use more specialist equipment. I know the Paris Metro actually uses aircraft tyres and I believe these are inflated to much higher pressures than road ones. This reduces the energy loss of a rubber tyre but it will still be worse than a steel wheel.

 

[starrymarkb]

The VAL in Lille is quite an impressive system. Fully Automatic (no staff apart from roving RPIs/Security), Platform Screen Doors at every station and up to 60tph in the peaks.

 

[jopsuk]

I'm not sure if they've implemented at all, but the Japanese Fastech 360 experimental bullet train was equpped with air brakes as part of it's emergency stop equipment- flaps that come out of the roof to make the train much, much less aerodynamic.

There is a bit that different braking works better at different speeds. For efficiency and to reduce damage a combination of braking can be optimal.

 

[142094]

Have any trains supplemented their braking capability with a brake block that is in contact with the rails?

A lot of trams and light rail systems have magnetic track brakes, but normally these are only for emergency use. Service braking is usually disc or rheostatic.

 

[theageofthetra]

I saw a german bus at a museum open day which ran on tyres like a normal bus and then some rail wheels lowered down and it ran on the track. The propulsion was I think by the rear tyres driving on the rail (a bit like the plant you get in rail engineering these days). There are pictures on the net (sorry can't post links on a mobile) of a huge Russian diesel loco which was mounted on an eight wheeled missile carrier chassis with the wheels powered by electric motors supplied from the diesel gen set. It was designed to provide mobile generator power on a battlefield but the project was abandoned in the early 2000's