NS Steam Program Speeds

p51 · **Posted:** Tue Feb 04, 2014 1:38 pm

Lincoln Penn wrote:

Overheard on the photo line during a UP 3985 trip in Wyoming in the early 1990s:
"Dang! They back up faster than NS goes forward!"

Some pals of mine from Florida came up to Portland to meet me at the NRHS convention in 2005, and we chased 4449/700 to Wishram. I was hauling down those roads trying to catch up, and one of the guys with me who had practically lived his life around the NS schedules back in the day asked, "Why are we going so fast? We must be miles ahead of that train by now!"
When I got onto I-84 and hauled East, he later saw the train ahead of us on the other side of the river. His jaw hit the floor of my SUV as he was totally unprepared for the concept that a steam excursion could be moving at what he always refered to as, 'Amtrak speeds'.

NH0401 · **Posted:** Tue Feb 04, 2014 2:52 pm

Don't forget that the trailing unit (an ES44AC in the case of 765) is probably transmitting all kinds of data back to Erie. No secrets out on the road anymore.

Dave

Alan Walker · **Posted:** Tue Feb 04, 2014 5:01 pm

Alexander D. Mitchell IV wrote:

hamster wrote:

Is there a physical speed limit, in RPM, for locomotives with conventional bearings?

The same guy I mentioned earlier, one of those math whizzes that can do complex algebra in his head, once sat and, simply as a thought exercise, calculated the RPM of the alleged run of a N&W J class (70-inch drivers) on the PRR at 110 mph, and extrapolated that it matched, within one or two, the RPM of an 80-inch-drivered London & North Eastern A4 Pacific at 125-126 mph. Our speculation centered around whether an American loco could have set the record had it been equipped with large enough drivers.

At such a stage of speculation, your bigger problem is constructing a robust enough valve mechanism and drive train. The LNER Gresley conjugated valve gear tended to run hot on the big end when such high speed runs were made.

Another factor to consider is the center of gravity and curvature. The Brits had at least one nasty accident that was the result of the engineman exceeding the overturning speed on a curve. A contributing factor was similarity of the 4-4-0 class involved-the sister class locomotives had a slightly lower center of gravity and could take a curve safely at a speed higher than the Drummond 4-4-0 involved.