I've just been asked this via PM and thought I'd post my answer here in case it is of interest to others too.Do 91s still have cruise control or has that been removed?
The 91 has a speed selector. You select your target speed and then apply the desired amount of power. The train will then accelerate up to the target speed providing enough power is supplied. It will then hold the train at this speed until you change the target speed, brake, or reduce power.