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Discussion in 'HO Scale Model Trains' started by 1GUNRUNNER, Apr 19, 2007.
In my continuing saga of newbie questions, where can I learn about grade limitations?
Welcome to The Gauge. Do you mean grade limitations as in how steep a grade can be before a train can climb it, or what prototypical grades are?
Most Class 1 railroads had grades below 2.5 percent. On logging railroads it to could be as much as 7 percent without the use of geared locos. When it comes to an HO scale layout you'll find steeper grades than protoype mostly in the interest of conserving space. An average HO scale diesel can climb a 4 percent grade pulling a dozen cars or so. Steam locos in general have less pulling power on steep grades unless they use a traction tire.
If you can narrow your question a bit we can probably address it for you without linking you to an outside source.
Hope that helps!
Thanks for your response. I was just wondering for a steam locomotive what is the steepest grade I can expect it to work on.
2% should be your maximum percentage of grade. You could go to 2 1/2% but that is quite a bit steeper. Take a lot at this site.
"It all depends" is unfortunately the answer. Depends on loco, manufacturer, traction tires (or not), well balanced & properly weighted (or not), if the grade has good transitions into and out of it, if the loco is properly maintained, if the grade is on a curve, if the track is dirty, if the consist is properly maintained and weighted, etc.
Best thing to do is to get as specific as you can - loco type and manufacturer, and the proposed grade (and curve if any) and see if anyone can give you information from experience.
But the general rule of thumb - all else being equal - is that 2.5% is about as much as you'd want to try, unless you are modelling logging lines with geared locomotives.
And in his other thread, he mentioned modelling steam logging operations.
Doh! Shoulda read that one first...!
Even then, everything depends. A loco by itself will climb a certain grade; with cars it climbs less grade; a bit of extra weight on the drivers may increase the grade again.
I find mine pull better as they age; I don't know if it's the drivers or the track wearing.
I believe the steepest grade climbed by steam locomotives in the US is 37.5% (3 in 8) on the Mount Washington Cog Railway, but then they don't rely on friction.
Thanks guys. I have a weird layout that will probably best told in pictures. I will try and get some up this weekend. with all of my thoughts, concerns, and questions all wrapped into one.
Apparently, model locos cannot match prototypical operations.
In the Rocky Mountains, constant average grades of 4% and transitional grades of 6% were not unusual and were handled by the locos of the day operating on narrow gauge track. Generally, the trains were small - three or four cars plus a caboose, and might require a helper. The real challenge lay in getting up to six or seven freight cars heavily loaded with gold ore back down that grade - in winter.
The longest train ever recorded on the Florence & Cripple Creek Railroad was a circus train that created a consist of twenty cars which required no less than five locos to drag it over the 6% final climb.
Now that would be fun to model!
I need to drop/climb 5' over a 28' run so I am guessing will be ok.
5 feet over 28 feet? Ummm... That would be a 17.86% grade!
Or was that a slip of the fingers and you meant 5 inches over 28 feet, which would be a very nice 1.49% grade. :thumb:
So I am gonna need a 250' run of track to get down to 2%?
You're trying to change your train's elevation by 5 feet?
Im running 8% with minor problems, pulling 4 passenger coaches weighted to standard. Biggest problem I having is the power supply acting up/dropping out. With the freights Im having no problems
Gun Runner - what are the actual measurements of what you want to do? What is your proposed elevation change?
There are other ways to change elevation if needed... Logging lines would use switchbacks, so that even though they need all the track, they would not have to run all the way around a mountain to do it.
In the model world, there are helixes, train elevators, and "cassettes", that can transport trains for one level to another. So unless you need to see the train actually climb the grade through the scenery, you do have other options.
Correct. (10 character minimum???)
I want to change elevation 5'. I have an unlimited amount of space off scene where I had hoped to make this happen in a 28' switchback. If I need 17, 14' switchbacks, it is gonna kind of take the fun out of it.
Ever thought of using a helix?
Here is something I tried and it works great.
I used 2" styrofoam, cut it 2 inches by 8 feet then cut it corner to corner, this left me with 2 perfect 2% grade 8 feet long, where I needed a curve I cut lines about 3/4 the way throw on both sides, glued and pined the styrofoam on the table top.