The Channel Tunnel Rail Link (CTRL) is signalled with a cab signalling system called TVM430. This is the same system as used in the Channel Tunnel itself, as well as on the high-speed lines in France. The letters "TVM" stand for 'Transmission Voie-Machine', which means 'Track to Train Transmission'. The number "430" refers to the theoretical maximum speed at which the system will operate, which is 430 km/h (267 mph). The maximum permissible speed on the CTRL is 300 km/h (186 mph).
An indication displayed inside the cab advises the driver at what speed, in kilometres per hour, the train may run. An audible tone accompanies any change of display.
A flashing indication advises the driver that the next indication displayed may be more restrictive than the current one. The change of indication will usually occur when the train passes the next block marker.
| Indication |
Description |
Meaning |
 |
Steady line speed indication for normal running. |
The train may proceed at the maximum permitted line speed, as indicated. |
 |
Flashing line speed indication for normal running. |
 |
Steady clear indication for normal running. |
The train may run at the maximum permitted speed for the train concerned. This indication is for certain types of trains that cannot run at the maximum permitted line speed. |
 |
Flashing clear indication for normal running. |
 |
Steady warning indication. |
The train's speed must be reduced to the indicated speed (or lower) as soon as possible. |
 |
Flashing warning indication. |
 |
Steady execute indication. |
The train must not exceed the speed indicated. |
 |
Flashing execute indication. |
 |
Stop indication. |
The train must stop at the next block marker (or signal). |
 |
Running on sight indication. |
The train must proceed cautiously through the block section ahead, being prepared to stop short of any obstruction. Speed must not exceed 30 km/h. |
