Sorry Huw, but all mainline steam in the UK is limited to 75 mph, although most would be happy to run higher than that.

Just as a little aside, if a 9f was running at 90 mph (It has been known! Including a fantastic run with the Red Dragon Express), the driving wheels (5 foot Diameter) would be turning at 8 revs a Second!! Anyone fancy calculating the acceleration of the pistons?

Wassail!! Chris