posted
I am doing a science project and I want to find out what is the steepest slope that a steam engine can climb? How many degrees to the slope? I think that it can't be much but I don't know.
Posts: 1 | From: Brooklyn, NY | Registered: Feb 2003
| IP: Logged |
posted
It depends on a number of factors - weight of the engine, weight of the train, weather, rails, etc. But there are few sustained grades (ie that go on for at least a mile) steeper than 4% (1 in 25, or 4 metres rise per 100 metres length). Even 2% is a heavy haul these days but that is a more realistic figure these days.
Geoff M.
Posts: 2426 | From: Apple Valley, CA | Registered: Sep 2000
| IP: Logged |
posted
Yes, there are too many undefined criteria in your question. Perhaps a few thoughts: 1. Is the train starting from a dead stop? 2. How long is the grade? A train with momentum can climb a grade of short horizontal distance. If the train is long (one mile) it can be partially located on both a negative (down) grade and positive (up) grade. 3. Are there other factors such as horizontal curviture which also contributes to resistance? Posts: 467 | From: Prescott, AZ USA | Registered: Mar 2002
| IP: Logged |
posted
I'd say a 4% sustained grade is approaching the maximum for a rod-type steam engine. Some of the D&RGW narrow guage lines had sustained grades of 4% worked by 2-8-2's (Cumbres and Toltec comes to mind).
However, Shays, Heislers, and Climaxes (geared steam locomotives) were specially designed to climb much steeper grades. Some logging railroads had grades greater than 9-10%. Granted, the trains were quite short, but 9-10% without cogs is pretty amazing. See http://www.cassrailroad.com for more info on these engines.
posted
Let me answer a more generalized question: What's the steepest possible grade on an adhesion railroad (excluding cog-wheel rack railways)?
Typical maximum mainline grades in the U.S. are 2.2%, although a few are steeper. The steepest of which I'm aware are:
1) West side of Tennessee Pass, DRGW (3%, but now out of service 2) Raton and Glorieta passes on ATSF (both 3.25%, but ATSF years ago built an alternate main line further south, with much easier grades, that carries most traffic now) 4) A short stretch of Saluda Hill in North Carolina (NS, former Southern) has a grade of 4.77%. This is also now out of service.
Northern Pacific, Great Northern, and Southern Pacific maxed out at 2.2% over the Cascades and Sierras. The original ATSF line over Cajon Pass had a 3.25% grade, but a new line was constructed in the 1920s with a 2.2% maximum grade.
Grades are also generall compensated for curvature. There is a formula for reducing grade based on the degree of curvature (curvature increases drag).
While it's possible to climb a grade of 8% to 10% with an adhesion locomotive, it isn't done in regular service. Some logging railroads might have had grades that steep (I believe Cass Scenic does on the line to Bald Knob). You sure can't haul much of a train on such a grade.
Posts: 614 | From: Merchantville, NJ. USA | Registered: Aug 2000
| IP: Logged |
Printer-friendly view of this topic
