When you wrote:
> My point was, that the Lausanne M2 is of the same make as Paris and Lille.
did you perhaps mean to say Paris and Lyon.
I've not visited Lausanne since the M2 opened, but my understanding is that it based on the Paris Metro rubber tyred system, as also used in Lyon and other places. However the only rubber tyre system I've ever heard of in Lille is a VAL (Véhicule Automatique Léger) system.
If I'm wrong and the M2 is a VAL or VAL-like system, then my question doesn't arise as there are no steel wheels or rails involved in that system. Whilst there are a lot of similarities, VAL cars run on rubber tyres at all times, and are exclusively guided by horizontal guide-wheels.