I have it on good authority (me) that a Garratt started off in Johm o' Groats the north of Scotland with a huge long train which weighed several thousand tonnes, by Inverness it had reached nearly 100mph, however the driver had to brake hard and the train swereved voilently, it went back and forth across Scotland dipped down into the NE of England where it took a voilent turn to the north of England covering all all the industrial areas, the train then pitched over to East Anglia only to be thrown back across the Midlands into Wales where it snaked around the Valleys. The driver threw the loco into reverse the resulting jolt took it over to London and the SE, the driver and fireman fought these violent manouveres and began to get som semblance of control as the train sped across the south towards Bath, Bristol and Gloucester, just when they thought they had brought the mighty beast under control there was one last vicious swerve that straightened up the train and shot it towards the south west, the valiant crew stopped the train at Penzance......What? it's true I swear it.