A temporary speed restriction at Carstairs in the Scottish Borders was enough to derail an attempt to beat a 36-year-old record journey time from London to Glasgow.
A special Avanti West Coast nonstop express on the flagship line took three hours, 53 minutes and one second to travel the 401 miles between London Euston and Glasgow Central.
The Pendolino fell 21 seconds short of the record set in 1984 by the Advanced Passenger Train (APT), which soon afterwards went out of service.
Although billions of pounds have been spent on upgrading the West Coast main line since the record-breaking run, the 21st-century train was limited to 125mph – while the APT could run at 140mph for some of its journey.
Network Rail had worked with Avanti West Coast to ensure that other trains did not conflict with the record-breaking run.
But a 90-second slowdown in southern Scotland, with the attendant braking and accelerating to line speed cost the attempt precious seconds.
The average speed for the run was 103mph.
A scheduled passenger train running on the same journey was also one minute late at Glasgow after encountering the same hold-up.
Mark Smith, the former British Rail manager who runs the Seat61.com international rail website, was on board.
“We’ve raised some money for charity, and highlighted the potential for train not plane between London and Scotland,” he said.
“It’s still the fastest train I’ve ever taken from London to Scotland.”