Does TVM cab signalling know the characteristics of the stock it’s fitted to?

[urpert]

Just a random thought that popped into my head while passing through the Tunnel a few minutes ago… does TVM know the maximum speed of the stock it’s fitted to? For example, if a 395 is given the “green” equivalent does the cab display show 300 (the max line speed) or 225 (the max speed of the stock)?

 

[hexagon789]

Just a random thought that popped into my head while passing through the Tunnel a few minutes ago… does TVM know the maximum speed of the stock it’s fitted to? For example, if a 395 is given the “green” equivalent does the cab display show 300 (the max line speed) or 225 (the max speed of the stock)?

The driver has to input the train characteristics such as maximum permitted speed, train braking capability etc

GWML ATP is similar in that respect

TVM will enforce a train limited to less than the maximum linespeed, at slightly above its permitted maximum.
At speeds over 160km/h, the threshold is 15km/h over the permitted speed - so a Class 395 could reach 240km/h before the TVM intervened with a brake application.

 

[urpert]

Fascinating, thanks!

 

[hexagon789]

On reflecton, the French KVB protection system requires the same data inputs, so I think that the TVM may derive it from this - it might be a bit much for the driver to key in the information while transitioning to a high-speed line at up to 220km/h.

 

[Irascible]

I haven't dug the docs out to actually recheck but from memory ( of sometime ago! ) there is a table onboard the train that matches TVM codes to speeds, so a 92 will have a different table to a Eurostar set for instance. Theoretically I guess the train could load a different table for a different route, but I don't think that's actually something that's done.