French to English Tech/Engineering Transport / Transportation / Shipping Railway network

In conditions of use for rolling stock on Luxembourg railway network, this term occurs once within a table summarizing compliance requirements, as follows:

Dispositif de changement de régime:
Régimes: G: P: R:

It is specifically relating to the specifications of the braking system, and this particular vehicle does have a 'device for changing the régme', but only offers 'G' and 'P', not 'R'.

Despite lengthy Internet research on train braking systems, I can't seem to come up with a plausible term to search for! In particular, I can't find what we call a 'braking régime' in EN.

I have found that 'G' and 'P' stand for 'Goods' and 'Passenger' under UIC terminology, but can't seem to find a bilingual ref. anywhere to what the 'régime' bit is.