Since planning my layout I have been noticing details more. The thing that really amazes me is the grades into some industrial sites and spur lines that I have seen. I was just wondering what would the steepest grade that an engine could push say a couple boxcars or tankers up? Where I live there is a Sears wearhouse that is halfway up a mountain and would be a hard push for any diesal.
While some RR’s decended a bit stiffer grades, few went up very steep grades without being some kind of special locomotive such as a logging loco or a cog RR. This should give you some concept of the kind of thing I’m talking about. Note that even this is a special loco.
http://www.childrensmuseum.org/themuseum/allaboard/index.htm
Now thats a bit on the prototype. Models are different. Most modelers like to stay at a 2% grade or less, though you can usually manage a few cars up a 4% grade in a pinch. Most of the time this tends to end up being a thorn in the side if it’s a very heavily traversed section of track. Trains struggle with the grade with only a few cars, and doubleheading a train with only 4 or 5 cars just looks odd, ya know? (Not to say that some prototype RR’s didn’t do just that!)
In real life, the US record steep grade for normal track is just under 6%, near Madison IN. The line runs up (literally) from the Ohio River towards Indianapolis. PRR had specially geared locomotives and a lot of special safety procedures to get cars up and down the hill.
In published plans, I have seen spurs as steep as 12% in spots where the track leads under a road bridge or similar. John Allen’s Gorre & Daphetid was supposed to have a 10% grade on some side trackage, but I do not recall details on that right offhand.
If you buy the Atlas Bridge and Trestle kit and put it on one end of a 4x8 loop, you might end up with a 10% grade on your mainline track. I remember as a kid trying to see how steep we could make the track and still get an engine to pull a train up it. We did a better job of making cars fall off the inside of the curve than anything else. (And Dad was not pleased at how we abused his engine.) I suppose you could get a ruler or measuring tape and see what your rise/distance ratios are, then let us know.
From what I’ve read, the practicable limit on mainline grades was set at 2.2% by the Baltimore and Ohio railroad during the 1830’s on its crossing of the Appalachians.
On the eastern half of the first U.S. Transcontinental railroad, the Central Pacific (later the Southern Pacific) building over Donner Pass set their maximum grade at 2.2%, though there is still a short section of 2.4% in the California Sierra at a spot called Blue Canyon. Also, the original Southern Pacific grade on their Shasta Line between Oakland and Portland surmounted Oregon’s Siskiyou Mountains on a very steep grade of 3.3%, until a new line was built to the east (the Natron Cutoff) with an easier grade of about 1.5%. The original Siskiyou line is still in use under another railroad.
The Western Pacific line in California through the Feather River Canyon was set at 1%, which also made the line some 80 miles longer than the neighboring SP Donner Pass line. Both lines are now owned by the Union Pacific.
I believe that the Southern Railway had a short section of 4.5% mainline in South Carolina (since inactive), and the Denver and Rio Grande route over Tennessee Pass in Colorado had several sections of 3-3.5% (the line is currently dormant).
In the West, many ruling mainline grades seem to be in the neighborhood between 2% and 2.4%.
For modeling purposes, I’ve kept my ruling grade at 2% on the Yuba River Sub, with a very short section of 2.4%.
Hope this helps.
Tom
My mainline grade will be 2% or less with the longest stretch a continuous 40’ up.I was wondering about some real life industrial spurs I have noticed that are very steep and was wondering what the legal limit is.
The “B&O rule” of 2.2% was a legal and funding threshold, not a practical limit, set quite arbitrarily. Had the B&O built to, say, 2.4%, that would likely have become the number inserted into the Pacific Railroad Act.
Tennessee Pass had some very short stretches of 3.3% in it as originally constructed to narrow-gauge, which were reduced to 3.0% by 1910. The ruling grade is 3.0%.
S. Hadid
If it’s possible to get a run at a short spur, the grade can be as much as 20%, and many railroad coaling trestles incorporated such a grade. These fell into disfavor not because of inability to push a car of coal up the trestle but because if one went up the track too fast one couldn’t get stopped before car and locomotive plummeted off the blind end.
If one has to start from a dead stop on the grade, 12% is more or less the upper limit for a locomotive and a single loaded car. If the rail is wet, rusty, covered with dead leaves, or greasy, the grade may be too much.
There are quite a few industrial tracks in service today with 8-9% grades for short distances.
S. Hadid
I’ve used a 3% mainline grade on a previous layout, with no problems to speak of.
Loaclly, there’s an industry which receives tankers and covered hoppers, which has about a 3-4% grade (on a curve) for a few hundred feet. I’m told that back in the 50’s-60’s and early 70’s, they would use Alco RS3’s to try to shove cuts of cars in that track with a running start and laying sand the whole way, and sometimes “didn’t make the grade”, quite literally. They would either have to double the grade (which is something for an industrial track), or use helpers (actually, use more power). Other times, they would hit the grade at 20-30 MPH, and be down to walking speed by the time it leveled out, if they were lucky. Of course, that industry probably handled 25-30 or more cars a day at the time.
Southern’s Saluda Grade was 4.7% for (I think) 3+ miles, with a few hundred feet at the top of 5% (either 5.1, or 5.01, my book says both in different places, I’m not sure which is the typo). It was active under NS until just a couple years ago. They did have problems with runaways, and built 2 runaway tracks back in the steam era (not sure what year), and had “switch tenders” who would leave the switches lined for the runaway tracks, unless they heard an uphill train, or the downhill train would use a certain whistle signal (again, unknown what it was) to indicate all was OK. Later, Southern took out one track, and converted the other to an automatic control with the advent of CTC. The upper track, IIRC, is still there.
Brad
According to a standard-gauge map I have in a book on the Rio Grande by Robert LaMessina, showing the profile between Denver/Pueblo/Tennessee Pass/Ogden, there is a short stretch of 3.55% between Minturn and Red Cliff. At least that’s what is shown in the book.
And Theodore Judah’s original surveys for the Pacific railroad in California between 1854 and 1860 set the grade at 2.2% BEFORE the Pacific Railroad Act was signed by Abraham Lincoln.
Tom
In Rockford, Illinois (heart of the flatlands) there’s an interesting STEEP grade. The C&NW comes into town on a higher level than the main part of town, on a high fill for most of its mainline. Below the C&NW runs the IC, CB&Q and Milwaukee, all of which duck under the C&NW at various points. There’s an interchange track between the Q and C&NW where the Q runs up to meet the C&NW on a 4% “ski jump”.
The interchange is still in use today, with Illinois Railnet running on the Q track, and UP owning the C&NW. I’ve watched IR trains run up the grade, and it’s fun to see; sort of like watching an F-14 launch off a carrier. The IR engineer will tack onto their 2-3 interchange cars, back up about 200 yards beyond the switch, and then slam into run eight fast. Their CF-7 shoots forward like a shot, runs up the interchange, and BARELY gets to the top without stalling out.
The limiting factor is called the Factor of Adhesion. At some point the wheels will just spin instead of gripping the rails. There was a Trains article all bout this back in the 60’s I believe. Railroads stay well below this because as the steepness increases the ability to do work (pull cars) decreases. European rails sometimes use a geared rack with a gear under the locomotive to increase the grade and maintain a decent work rate. That is why keeping the grade as low as possible benfits the railroads. Even so there are numerous locations where trains have to double a hill because they can not pull all the train in one movement.
twhite, the Pacific Railroad Act of 1862 mandated a ruling grade on the transcontinental railroad not to exceed the ruling grade found on the Baltimore and Ohio Railroad . . . . . and that happened to be 1:45 or 2.2%. There were/are several sections over the Sierras or through the Wasatch - but not on Sherman Hill which is impressive but, operational wise, is somewhat of a wimp - where the maximum grade exceeds that mandated 2.2%. Both the Pennsylvania Railroad’s 5.7% grade out of Madison, Indiana and the 4.7% Saluda grade on the Southern Railway astride the North Carolina-South Carolina border are not only maximum grades, they are also ruling grades.
Now to BATMAN’s question: industrial trackage is frequently built on grades exceeding that which appears on the surface to be prohibitively steep. Industrial trackage can - and frequently does - exceed 5 and 6 percent. Trackage this steep is likely to only be the province of short consists or, as is the case on some coal spurs in the Appalachians, negotiated only by empties on the upgrade. Unloading trestles in urban areas can be very steep but the maximum in this case will probably not be the rulling because it is extremely unlikely that the full length of the train - unless very short in which case it doesn’t really matter - will ever completely be on the grade at any one time.
Don’t be deceived by size: switchers may not have a lot of speed but they do have a lot of muscle!
If you are not thoroughly confused by this time you simply do not understand the situation!!!
R.T.
The reason I mentioned the 2.2% ruling grade for the Pacific Railroad Act was that many of Judah’s alternate surveys in the Sierra between 1854 and 1860 were in canyons (American and Yuba River watersheds) that he found out would require a far steeper grade than 2.2% to climb out of to reach the Sierra watershed divide. Among the other passages surveyed were lines up the North Fork of the Yuba River over either Henness or Yuba Pass, and a survey up the South Fork of the American River to Echo Summit. All of these rivers end in ‘bowls’ far below the actual passes, so when he found the unbroken ridge route between the American and Yuba River watersheds, he realized that the railroad could be built with a 2.2% ruling grade all the way to Donner Summit. Of course, you’re right–the grade exceeds 2.2% in several places–in fact the initial grade between Rocklin CA and Colfax, CA, is almost a steady 2.4% (now the Westbound track). However, above Blue Canyon, the grade eases considerably on the Yuba River side of the ridge, clear up to the Summit.
But any canyon-bound routes on the other surveys would have required probably a 3-3.5% grade to lift the tracks out of the canyon and over the Sierra watershed divides. Judah chose well.
Tom
You also need to be concerned with the rate of grade change, or vertical curve. Too sharp a curve and some drivers (if more than two axles) will lose contact with the rail, pilots and steps will strike the rail, the cars will uncouple.
Mark
That’s a very good point!
Also when wheels make poor rail contact their ability to check the train under braking is reduced…
This leads me to the point I wanted to add…
Both going up and down steep grades the loco and cars need to be able to stop safely.
It isn’t uncommon for short “switching” pushes (and pulls) to use a burst of speed to get loco and cars up a short steep grade… what we need to recall is that the engineer (or someone at the head end) needs to be able to see where things are going and have safe distance to bring it all to a stop.
While short sharp shoves may be virtually ground to a halt by some severe grades the RR and staff will usually try to organise things so that they have a chunk of power to spare. This is better than stalling on the grade and having to negotiate the run back down to the bottom. this means that these moves tend to pop out at the top a bit “sharpish”.
Weather comes into this. That’s weather not “whether or not the train will make it”. Any wet on the rails may mean that the shove over the hump is cut down by a car or two. When things get really bad one car may be worked at a time. Seasons afect this with leaves being the common problem… although frogs and toads have their days.
As I said loss of traction affects braking as well as getting the loco and cars up a grade. You may have already guessed that I’m going to say that this matters for trains that stall and have to get back down to try again (because they can’t achie
A logging operation in Michigan (Porterfield & Ellis, I think) had short grades of 20% in its operations. Rather than build a lengthy trestle across a river basin, they stuck to ground level and lived with the steep grades to get out of the basin. Needless to say, these grades were scaled mainly by momentum, and a logging train that didn’t make it out had to rock its way back and forth across the basin until it reached the top.