User:Sladen/ListTest

Original test case from Rubber-tyred metro.

Advantages and disadvantages
The essential difference between rubber-on-concrete and steel-on-steel is that rubber-on-concrete generates more friction. This results in various pros and cons.

Advantages
Advantages of rubber-tyred metro systems (compared to steel wheel on steel rail):
 * Smooth ride with (with little "jostling" around)
 * Faster acceleration¹
 * Shorter braking distances, allowing trains to be signalled closer together
 * The ability to climb or descend steeper slopes (~gradient 13%) than would be feasible with conventional rail tracks.
 * Quiet ride in open air (for residents and those outside the train)


 * 1) Modern steel-on-steel rolling stock using distributed-traction with a high-proportion of powered axles, have narrowed the gap to the acceleration/performance found in rubber-tyre rolling stock.

Disadvantages
The higher friction causes disadvantages (compared to steel wheel on steel rail):
 * Higher energy consumption than steel-on-steel


 * A larger quantity of excess heat is generated
 * Weather variance. Loosing the traction-advantage in inclement weather (snow and ice)¹
 * Heavier; steel rails remain for switching purposes, and as a safety backup²
 * Tyre replacement cost³
 * 1) To reduce weather disruption, the Montreal Metro runs 100% underground. On Paris Métro Line 6, upgrades of tyres (as used with cars) and special ribbed tracks have been trialled.
 * 2) In effect, there are two systems running in parallel. This is more expensive to build, install and maintain.
 * 3) Rubber tyres have higher wear rates and therefore need more frequent replacement. Although a steel wheels set is more expensive than a pair of tyres, the frequency of their respective replacements makes rubber tyres the more expensive option. And in addition many rubber tyres for guidance will be needed, too.

Although it is a more complex technology, most of rubber-tyred metro use quite simple techniques, in contrary to guided buses. In regard to the dissipation of heat: eventually all traction energy consumed by the train — except the electric energy regenerated back into the substation during electrodynamic braking — will end up in losses (mostly heat). In frequently operated tunnels (typical metro operation) the extra heat from rubber tyres is a widespread problem, necessitating ventilation of the tunnels.