Pendolino Tilt System

Class 390 Pendolino Tilt Facts and Figures

Each nine coach Class 390 includes:

Coach K Coach J Coach H Coach G Coach E Coach D Coach C Coach B Coach A

Tilt System (Alstom Tiltronix)

Tilt System Operation

Sensor Unit Tilt (SUT)

Two units are located on each leading bogie of vehicles A and K. The SUT contains gyroscopes to detect when the train is tilting and accelerometers to detect lateral acceleration of the train. This information is passed to the TTP which calculates the tilting angle for each car as it travels through the curve.

The SUT also measure the distance that the train has travelled between each balise and therefore knows when to expect another balise.

Train Tilting Processor (TTP)

The TTP is actually the Vehicle Tilting Processor of the driving cab vehicle. It is activated to become the master TTP by the cab of that vehicle being active.

Receives data from the TASS balise about tilt authorities and speed profiles for the section of track ahead via the TASS vital computer.

Receives data from the Sensor Unit boxes on the leading driving bogies about the speed, cant angle and distance travelled.

Using this data the TTP calculates when the train has to tilt and by how many degrees. This constant stream of data is passed to the VTP on each vehicle.

The TTP constantly monitors the safe operation and behaviour of the tilt system ensuring, that if there are any problems, the train will fail safe, with the tilt system self centring and an emergency brake application if required.

Driver Unit (DRU)

Receives data from the Vehicle Tilting Processor (VTP) informing it of when and by how many degrees the bogies controlled by the DRU have to tilt.

Activates the drive command on the bogie actuators to tilt the bogie bolster to the required angle of tilt.

Monitors the safe operation of the electro-mechanical system on the bogie and provides data back to the VTP.

On pantograph vehicles there is also a Driver Unit Pantograph (DRUP) which carries out the same functions and checks for the pantograph tilt mechanism.

Bogie Actuator Operation

Tilt System Bogies

The movement of the tilting bolster, which tilts the car body is controlled by an AC servomotor known as the bogie actuator.

The motor moves in a linear fashion via a planetary screw drive linked to the tilting bolster which sits on roller bearings.

The bogie actuator moves position in reaction to voltage commands by the DRU which meet the required amount of tilt angle required by the system.

With power removed to the bogie actuator, the servomotor will allow free movement of the bogie bolster back to its default position of self centred.

Tilting Pantograph Operation

A Brecknell Willis high speed pantograph mounted on a tilting cradle which is operated by a electro-mechanical actuator.

The actuator operates a belt drive to pull and push the pantograph to the required tilt angle as determined by the Driver Unit Pantograph (DRUP) via commands from the VTP for that vehicle.

If the pantograph is detected to be at the wrong angle, the pantograph will fast auto drop and a passive centring device will restore the pantograph cradle back to the centre position.


If you have any information on Class 221 'Super Voyager' Tilt Systems - Please let me know !

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© R G Latham 2024.