This bug report does not cover the case of underpowered ghost trains.
In some other cases ghost trains, used in MSTS activities to perform synchronizations, run at lower speed than under MSTS.
This is due to the fact that there are some speed bands between practical max allowed speed and max theoretical allowed speed, when the ghost train is running in RUNNING mode. Even if these bands are quite small, they can increase very much the time needed to run the ghost train path, because percentually the speed reduction is very high.
As OR already behaves differently in BRAKING mode, and as a creeping speed is already defined, it is reasonable to zero the bands when the speed is lower than the creeping speed and the train is in RUNNING mode. This in practice occurs only to ghost trains.
Fixed in x.3506.