In the book Speed on the East Coast Main Line by P Semmens there are two graphs showing the speed achieved by 4472. Both would have been created by hand from the time and distance dynamometer car roll (marks made every second on paper passing at 12" per mile). Oddly they show different speeds during the descent from Stoke and as far as I can see neither shows a speed of 100 mph. One clearly shows 98 mph, the other 99 mph when you look closely. As far as I know the original dynamometer roll no longer exists. Would be interested to know if anyone knows better or if anyone has a better quality copy of the speed graph.