TECHKNOW: Pushing the envelope - Tilting trains

TECHKNOW: Pushing the envelope - Tilting trains - Despite the present disarray, there are still plans to make the trains run faster on son-of-Railtrack's iron highway. Virgin has ordered 55 high-speed tilting trains from Italy's Fiat. The Pendolino trains

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Last Updated: 31 Aug 2010

Despite the present disarray, there are still plans to make the trains run faster on son-of-Railtrack's iron highway. Virgin has ordered 55 high-speed tilting trains from Italy's Fiat. The Pendolino trains - Italian for pendulum - are being tested and are due to begin service on the West Coast main line next year.

THE CHALLENGE: To go faster, trains need straight tracks, tilting carriages or a combination of the two. Virgin wants to slice 80 minutes off the London-Glasgow journey time over a route that in rail terms is more like a winding B-road than a motorway, so tilting trains are the obvious choice. Even a slight curve can make passengers feel odd in a conventional train, but by reducing the centrifugal force experienced by passengers, tilters can go up to 30% faster.

The idea isn't new, but making it work has taken a long time. Initial French efforts in the 1950s were followed 20 years later by British Rail's spectacularly unsuccessful attempt, the Advanced Passenger Train. The problem was twofold. First, the technology was unreliable; the trains often became stuck on full-tilt. Second, the degree of tilt cancelled out the sensation of going round a curve, creating a mismatch between vision and balance that left passengers feeling queasy. The project was abandoned in 1984, and the sole surviving APT is now quietly decaying in a siding at Crewe.

THE SOLUTION: The Italian government started work on the Pendolino shortly after the APT debacle and learned from British Rail's mistakes. Using trackside beacons to trigger the tilt mechanism helps reliability - with almost two decades of service under their belt in Italy, Pendolinos are very much proven technology. And the sickness problem has been eased by reducing the tilt.

Virgin's Pendolinos will run at 125 mph initially, but if and when the West Coast main line upgrade is completed they will be able to reach 140mph. At present trains are restricted to 110 mph.

Although the Italians and the Brits have both opted for tilting trains, the French, those undisputed masters of modern rail travel, have opted for very straight railways. It works - their TGVs routinely top 180mph.

But the ultimate in high-speed rail travel will be achieved by Japan or Germany, both of which are constructing MagLev (magnetic levitation) lines. These dispense with wheels entirely, thus eliminating friction, vibration and the risk of broken rails. The countries' respective rail operators confidently predict speeds of more than 300mph. The Pendolino is a step in the right direction but, compared with the best, Britain's trains are likely to remain slow coaches, even at full tilt.

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