Tilting train: Meaning (information, definition, explanation, facts)

A tilting train is a train with a tilting mechanism that enables increased speed on regular railroad tracks.

Introduction

Curved railroad tracks are usually tilted. The particular angle of tilt ("superelevation") is based on the normal line-speed and has the effect that at this speed the passengers do not experience the effects of centrifugal force. This makes the ride more comfortable. The disadvantage is that if a train halts on a curve, the tilting is not comfortable.

If a train moves faster than corresponds with the tilt angle of the track then the passengers do experience (part of) the centrifugal force, which is not comfortable. This restricts the allowable speed more than the (essential) requirement that the centrifugal force does not push the train off the track—that would happen only if the speed were much higher.

Tilting trains are trains the upper part of which, where the passengers are seated, can be tilted sideways. In a curve to the left, it tilts to the left to compensate for the centrifugal push to the right, and conversely.

The train may be constructed such that inertial forces themselves cause the tilting, or it may be actively induced by a computer-controlled mechanism.

In the 1970s and 80s, following the success of its InterCity 125, British Rail built a tilting train called the Advanced Passenger Train. British Rail was never able to make the train reliable enough to go into service and so the project was scrapped. During tests passengers reported that the tilting motion made them nauseous. Subsequently it was learned that this could be prevented by reducing the tilt slightly, so that there was still some sensation of cornering.

One of the first trains with tilting technology was Deutsche Bahn's class 403, used for airport transfers between Düsseldorf and Frankfurt some decades ago (see also: AiRail Service). An attempt was made to use tilting technology to improve speeds on the extremely twisting Rhine Valley route. Shortly after the train went into service, the tilting technology was disabled as many passengers experienced motion sickness due to sudden and heavy tilting.

Some tilting trains run on narrow-gauge lines. In Japan there are many narrow-gauge lines in mountainous regions, and tilting trains have been designed to run on these. In Australia the link between Brisbane and Rockhampton, which uses tilting trains, now claims to be the fastest narrow-gauge link in the world.

Trains with tilting by inertial forces:

• Talgo XXI (Spain)

Trains with tilting controlled by a computer:

• ICE-T, also called ICT (Germany), tilting version of ICE
• X2 with tilting mechanism of ABB (Sweden)
• Pendolino (Italy and Britain), built by Alstom - formerly Fiat
• Pendolino (Finland)
• InterCitySlovenija - high-speed tilting train in Slovenia operating between Ljubljana, Maribor and Koper.
• Acela - American high-speed tilting train operating between Boston and Washington.