Track slope??

Affiliate Disclosure: We may receive a commision from some of the links and ads shown on this website (Learn More Here)

#1
What are acceptable track slope percentages? Are straight and curves the same. I see 3% mentioned on and off. Is that a good number? I'm talking about N. To me a 3% slope is a rise or fall 3 inches in 100 inches. Is that correct?
Just don't want to have to redo anything.

Thanks!
 
#2
You are on the right track (pardon the pun ;) ). The term commonly used for that percentage is "grade". If you do some searches here on this forum and generally on the web you'll find lots of discussion about reasons for all sorts of different grades. But the most commonly accepted maximum grade is 2%, regardless of scale (grade is grade, regardless of scale). The real railroads are typically more like 1% on their big class 1 main lines, and rarely go over 2% outside of that. Though there are instances in the real world of excessive grades. The Cass Scenic Railroad even claims grades of greater than 8% http://www.cassrailroad.com/ , though they're using Shay locomotives which were designed for that sort of thing.

There are even equations for determining how much load your locomotives can pull at different grades, but likely a small layout which requires steeper grades would be running shorter trains anyway, and steeper grades could be more acceptable. You might be able to go as steep as 4 or 5 %, depending on the quality of your locos and rolling stock.

You also mentioned curves. Curves can increase the rolling resistance of the equipment as it grinds a bit more on the rail while going around a bend. Even on flat track this is true. So compounding a curve with a grade will certainly increase the workload on your locomotives and should be taken into consideration. I believe there might be math equations available for calculating these values too.

Good luck!
 
#3
Thanks, that confirms what I thought. I just want to add some height differences around my layout to sort of get away from an all flat layout. And to allow some intersting bridges over rivers and the like. I'm building on 1 1/2" blue foam so I think it will be fairly easy to add these sort of features.
 

cajon

Active Member
#5
If you're into narrow gauge, the Uintah Ry (UT) had some 7.5% grades on 65 degree curves & they ran a couple of 2-6-6-2s there!
 
#6
I had a look at the woodlands senic stuff, thanks. Looks like it would be helpful. I might try making something simialr myself and if that is a issue or PIA, I'll try their stuff. I've done quite a bit of foam cutting before in a different hobby.
 
#7
I had a look at the woodlands senic stuff, thanks. Looks like it would be helpful. I might try making something simialr myself and if that is a issue or PIA, I'll try their stuff. I've done quite a bit of foam cutting before in a different hobby.
I've considered making my own as well. With appropriate jigs I think the flexible slopes could be produced rather quickly. But if you're only making a dozen or less, is it worth the time figuring out how?
 
#8
You might be able to go as steep as 4 or 5 %, depending on the quality of your locos and rolling stock.
That would be the exception, not the rule, in my experience. Most model railroaders in most situations are much happier keeping grades below 3% for reliability, especially through curves, which add to the effective grade.

Responding to another post, the Uintah Railway is the exception of all exceptions (that's why it's famous) and should not be suggested as an example to follow in the model -- just my humble opinion.

Also don't forget that you will need transitions into and out of grades .. and these need to be longer for steeper grades. This uses up some of the length of the run.

 

Selector

Active Member
#9
The maximum standard grade for railroads on both sides of the 49th parallel is 2.2%. That was fixed by Congress in the early 1800's due to the success with that grade, but also the troubles inherent in it, by the Baltimore & Ohio Railroad. Since Canadian rail progress closely mirrored the experience in the USA, the CPR adopted that standard as well.
 
#10
I had a look at the woodlands senic stuff, thanks. Looks like it would be helpful. I might try making something simialr myself and if that is a issue or PIA, I'll try their stuff. I've done quite a bit of foam cutting before in a different hobby.
Check my build thread (link in my sig) on using foam for track grades.
Since you have done foam cutting (airplane wing core?) you should not have any difficulties with track grades.

Do study cuyama's grade transition diagram. These are important for smooth running.
 



ModelRailroadForums.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com