Say if it was a branch line or siding, what is the steepest grade an engine can push or pull 1 car up successfully without a cog system? What engine would be the best one to do it with?
It’s well known that Madison Hill in southern Indiana, now out of service, is the steepest adhesion grade in the United States at 5.89%. There were also some steeper grades run on momentum on some logging roads in the Upper Peninsula of Michigan. I would think that the theoretical maximum would be between 7% and 8%.
I was thinking it was the Boeing plant in Mulkatio WA , but I don’t remember the Grade .
My recollection of what I’ve read and seen in the past about Cass Scenic RR makes me want to say 14 percent, but the on-line sources I just checked indicate a maximum on Cass in excess of 8 percent. If I find anything more definitive in my library at home, I’ll post it.
The Boeing plant’s spur line is between 5 and 6 per cent, if I recall correctly.
Cass Scenic Railroad in West Virginia routinely operates up approx. 10 per cent grades - on switchbacks, too - as traction-only - with Shays and other geared lokies. If you haven’t seen it in person - put it on your list for ‘someday’.
The Michigan logging road grades ranged from 20 to 45 per cent, if I recall correctly - but yes, they were run strictly as momentum grades.
The theoretical maximum would depend on the relationship between the total weight of the engine plus the car, and the weight on the driving wheels and the factor of adhesion/ coefficient of friction. Real roughly, if all weight is on the drivers, and the car weighs about the same as the locomotive, the maximum grade would = about coefficient of friction x (weight on drivers/ total weight) - or for a coefficient of 0.25, about 0.13 = 13 per cent grade - not much more thatn what they do at Cass. But there, a pretty burly 3-truck Shay is pushing only 3 or 4 flats-as-passenger-cars up the grade - and I don’t think the whole train is ever on the steepest part of the grade all at the same time.
- Paul North.
The steepest adhesion worked grade in the UK was Hopton Incline on the former Cromford and High Peak Railway, at 1 in 14 (7.14%). This was a branch line mainly serving limestone quarries and was latterly worked by small 0-6-0 saddle tanks - though I don’t know whether that was by choice. The C&HP was ancient and bizzarly engineered. Like a canal, it was all either dead level or savage incline, with nothing in between. Hopton was actually one of the gentler inclines, as most were rope worked, and the engines had to be roped up and down these too. As the level sections hugged the contours the line also had severe curves - one of 55 yards radius being the sharpest on a British running line. Therefore, large engines weren’t an option.
Wikipedia lists some steeper grades: http://en.wikipedia.org/wiki/Grade_(slope)
The Postlingbergbahn in Linz in Austria claims to be the steepest adhesion railway in the world at 11.6%. Recently re-gauged from metre to 900mm and through connected and operated with the Linz tramway system which is this rather odd gauge. Lisbon is the only other system I’m aware of that shares it.
Kind regards,
Andrew Harper
Bo’ness, West Lothian, Scotland
AFAIK, Pöstlingbergbahn in Linz runs with EMUs with all axles driving. It had additional brakes for safety reasons. In Laon (Northern France), a similar operation ran at 12 % with a rack-and-cog-system for emergency-braking.
The Central Railroad of Peru has 8% ruling grades from Limy to Oroya in the Highlands (Altiplano) of Peru and runs real, albeit short, trains. Until the Chinese opende the railroad to Lhase, it used to be the highest railroad in the word (3 miles high)
In Switzerland, the Bernina-line and the Montreux-Oberland-Bernois (both tourist-lines, meter-gauge) habe 7% ruling grades, as well as the Uetliberg-Railroad (standard-gauge, suburban-traffic in Zurich). AFAIK, the former tramways in Lausanne and Geneva had even steeper grades.
I have stood at the foot of Madison Hill–it was actually a profound moment of reflection. I was simply in awe at the 5.89% grade, and had a hard time picturing a single Pennsy SD-9 pulling more than two cars at a time up that thing (although it is my understanding that they did).
Hearing of 12% grades and thinking of Madison makes me think that there has got to be a little more too it. There is a road on the side of Madison Hill. I am not saying that it was in danger of stalling or anything, but you could tell that my car was really working to make the grade. I dare say, my car would not have made it up a grade of 12%, and I have a hard time seeing how a train could. Then again, I should not doubt anything until I see it.
Gabe
Gabe:
I certainly am not doubting your story on assending a 12% grade with {your}, car. I dont’ know the specific circumstances. I will say, there is a {paved}, street / road at the edge of our small home town {in Pennsylvania}, and right next to my home location…with a grade of roughly 12 to 13%.
Any production {stock}, automobile will easily climb that grade. It was constructed in 1937 to clear Rt. 30 when it was moved out of town to bypass said town. And boy it sure was good to sledride on before the crews got to it with the {then}, ash / snow plow truck when it snowed.
I have driven a 25,000’ GVW test truck up a 19% grade many years ago.
Gabe,
As I recall, Pennsy ordered two SD9s that were assigned only to this line. They were modified with a lower gear ratio, and heavily ballasted to increase traction. I think they also had slightly larger than normal air compressors, and an early version of extended range dynamic brakes.
Uintah Railway in Colorado and Utah had 7.5% ruling grades and 66-degree curves, operated with both rod-type and geared locomotives.
RWM
An AC44 would only need to exert 100000 lb TE to pull a 100-ton car up a 15% grade. Any reason to think it couldn’t do that-- even after multiplying its weight by the cosine of the angle?
The SD9’s used on Madison Hill did have modified air compressors to assist in the operation of a rail washer. This was used to remove leaves on the rails to prevent slipping, primarily during the fall season.
RWM -
Were those Uintah Rwy. rod engines ‘tank’ types - which would have a larger proportion of their weight on the drivers - or with tenders, which would be all ‘dead’ weight ?
- Paul.
Paul mentioned momentum grades on Michigan logging railroads. I have never heard that term, but it fits the circumstance. One example was the Pori Loop Line about 20 miles or so southeast of Mass City, MI. This standard gauge line had 20% grades operated with rod engines. They ran down one 20% river valley grade, reaching 60 mph, in order to develop sufficient momentum to climb out of the river valley on another 20% grade.
Sometimes they would stop to take water out of the river. Then they would pull forward up the 20% grade until they stalled. Then they would reverse and run as fast as possible back up the opposite 20% grade until they stalled. They would repeat this, see-sawing back and forth until they made it to the top on one side or the other.
timz -
Nope - seeing as how said AC44 outweighs that car by almost 1.5- or 2-to-1, and probably achieves a Factor of Adhesion in the range of 2.5 to 3.0 (Coefficient of Friction of 0.40 to 0.33, respectively).
Using the lower-performance value, it would probably be good for that on a grade of up to 20 or 22 % ( 0.60 to 2/3 of 0.33).
Assuming that the AC44 weighs around 400,000 lbs., and achieves a Coefficent of Friction of 0.35 ==> 140,000 lbs. Tractive Effort;
If that 100-ton car is it’s nominal capacity, it then has a gross weight of 263,000 lbs.; on a 15% grade that would require about 40,000 lbs. of TE to pull it up, thus leaving about 100,000 lbs. of TE for the loco to pull itself up, as you say. On 15%, that 400K loco will need 60,000 lbs. TE to do that, leaving a surplus or left-over TE of about 40,000 lbs;
If we take that 40,000 lbs. and use to it find out the max. grade the AC44 and the car can get up, it would be an additional 40,000 / (400,000 + 263,000) = 6.0%, for a total of 21% - right in between the 2 values I’d estimated just above. Done ! [;)]
- Paul North.
Paul
Both, but on the steeper portions I have only seen pictures of tank engines, Uintah did have a shay.
See here , at 1:00 and 2:20 shows the big tank engine.
I’m no authority on the road but have a fleeting interest in it over the years, it could be the tender types made it up grade as well.
Edit: found another showing motive power here. You may wish to mute the volume.
Bucyrus -
Yes, but I was merely following-up on a mention of those railroads in a previous post by someone else here. And that’s my undestanding, too, of how those operations were run - not only to take on water, but to pick-up and drop-off log cars from the occasional spur that was down in the valley as well. See:
World’s steepest adhesion railroad?
Trains, June 1969 page 42
15- to 20-percent grades
( GRADE, “JONES, CLINTON, JR.”, LOGGING, MICHIGAN, TRN )
I see that I don’t recall correctly - the grades were as stated above, not as per my previous post.
Momentum grades are sometimes encountered or run as such on mainline railroads, too, even in this day and age. They can be anyplace - such as a ‘hogback’ or ‘sawtooth’ grades or profile - where the speed or ‘velocity head’ of a train coming down one grade is used to mostly get the train up and over an opposing upgrade that is not too far away. Also, the upgrade is short enough that not all of that inital speed is ‘bled off’ in climbing the grade such that the engineer then has to rely mainly or solely on the tractive effort and horsepower of his locomotives to get over the grade. However, as might be imagined, those operations are not always consistent with good train handling practices, or not possible where the
Sure looks like a well-sceniced model railroad, with the usual sharp curves . . . oh wait, that guy standing on the moving flat isn’t good modeling, and the smoke is just too real . . . [swg]
A Mallet - 2-6-6-2-T - and 36" narrow-gauge, too, if that hasn’t been mentioned yet.
Thanks for sharing !
- Paul North.