That would be hard to prove either way, but I wish I could have seen and heard it on that run. There is a good article on Wikipedia with many details. There were several stopwatches on the 999 train during the record run, so I lean toward believing it. The 999 was running a high pressure boiler and it had drivers 86.5 inches in diameter. Start doing the math, and the drive wheels turned 233 revolutions per mile. At 100 mph, it would do a mile in 36 seconds, and be running at 389 rpm. A limitation to high speed is the flat-faced D valves in the steam chests. As boiler pressure goes up, there is more weight pressing the valves to the cylinders, and that is why locomotives were soon switching to piston valves. Many Thanks, Merle for spotting a great video.
Nice film. But no real answers.
ReplyDeleteI've been in cars that were going 85 miles an hour when driving out west, and maybe a bit faster.
The mile markers were clearly visible and the mention in the film of markers going by in a blur sounds like advertising hype.
Two factors not mentioned were wind speed and direction and whether the grade was flat or downhill.
If I had to make a statement, I would suggest that since the speed run was not ever repeated, that might suggest that the speed wasn't reached.