grade question


J

jim81147

Active Member
Is 1/4 to 3/8 of an inch per foot an acceptable amount of grade for decent operation? I want to add some mountain terrain to my layout , but don't want the track so steep that I have to make up multiple engines just to pull up a couple boxcars . My layout is late steam / early diesel . Could I get away with going a bit steeper grade? Any practical experience is appreciated.
 
That would be a little over 2% to a little over 3% grade. Very acceptable in model railroading. For a short train of just a half dozen cars or so, most locomotive shouldn't have a problem.
 
Jim,

Just so you know, the "formula" for working out your grade is an easy one and based on a total length of 100", ie:

A vertical of 1" over a horizontal of 100" = a 1% grade
A vertical of 2" over a horizontal of 100" = a 2% grade and so on.

Therefore, a vertical of 1/2" over 50" horizontal = 1%
1/4" vertical over 25" horizontal = 1%
1/4" vertical over 12.5" horizontal = 2%
 
wombat457 said:
Jim,

Just so you know, the "formula" for working out your grade is an easy one and based on a total length of 100", ie:

A vertical of 1" over a horizontal of 100" = a 1% grade
A vertical of 2" over a horizontal of 100" = a 2% grade and so on.

Therefore, a vertical of 1/2" over 50" horizontal = 1%
1/4" vertical over 25" horizontal = 1%
1/4" vertical over 12.5" horizontal = 2%
Click to expand...

Thanks! THAT is the most clearly understandable explanation of this I've ever seen!
 
Don't forget, you will need transitions at the top and bottom to ease your trains into and out of the change of levels.
 
I have wood blocks cut in half inch increments that I space two feet apart when planning grades.
This is about a two percent +\- grade, makes it easy to plan.
 
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To cheat even more, 8 ft is 96 in which is close to 100, so you can use 1" in 8 ft = 1%, etc. Using step blocks is a very easy way to do grades. Make one for each of your level lengths. If you have a 24" level then make steps of 1/8", each step = 1/2% grade. Set the low end of the level on step of the desired % grade, then raise the high end (or lower the low end) until the level is level. That will set the grade.
 
dave1905 said:
to cheat even more, 8 ft is 96 in which is close to 100, so you can use 1" in 8 ft = 1%, etc. Using step blocks is a very easy way to do grades. Make one for each of your level lengths. If you have a 24" level then make steps of 1/8", each step = 1/2% grade. Set the low end of the level on step of the desired % grade, then raise the high end (or lower the low end) until the level is level. That will set the grade.
Click to expand...
imagesOYNA1P5Isssssssssssssssssssssssssssssssssplendid.jpgsplendid!
imageswiley coyote.jpg
 
tootnkumin said:
Don't forget, you will need transitions at the top and bottom to ease your trains into and out of the change of levels.
Click to expand...

Can you explain these transitions for me? I would guess they are just an area of very gradual shifting ( either up or down ) but is there a certain formula to follow? Thanks Tony , listed like you have is very easy to follow.
 
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That's what a transition is. A gradual change from level to incline or incline to level. The same applies to curves.
 
That is hard to answer. It would depend on the locomotive. A 3.5% grade is a bit stiff. It would totally depend on what locomotive you use and how well it pulls.

I purposely built in a 2% grade to limit the amount of cars a train can pull. An average locomotive, say a GP=9 or an Alco RS-3 can manage about 14 cars+ a caboose on the 2% grade. A steam locomotive, say a Consolidation (2-8-0) can only manage 7 to 8 cars on the same grade. I have a little Bachmann 2-6-0 that is lucky to handle 5 cars.
 
I had a 3.5 grade helix and didn't have any problem going up. The problem I had was with a 40 car freight going down. Near the bottom of the grade the large amount of cars had so much weight pushing on the train at the bottom it derailed the cars. Lucky I had 2 ways it could go down the grade and ran the larger trains down the straight route. I think a 1.5 grade would have been better for large trains, that is 40 cars or more. I took the helix down last year just to make more room in the basement. I'm to old to be ducking under to much bench work. If you never seen the video of the helix here's the link.

https://www.youtube.com/watch?v=uyzgL8tRKic

Geore
 
jim81147 said:
Can you explain these transitions for me? I would guess they are just an area of very gradual shifting ( either up or down ) but is there a certain formula to follow? Thanks Tony , listed like you have is very easy to follow.
Click to expand...

If you're cutting strips into your plywood and bending those upward to form your grade, the transition will pretty much just take care of itself. Plywood won't just bend sharply at an angle, but will gradually curve into the grade. If you're using foam or something you'll want to simulate that same effect rather than just going straight to your 2% grade. Same applies at the top, in reverse.

While very long locos like the DDA40X that was talked about might bottom out the fuel tank at the top, most locomotives (and some cars) will actually have problems with the couplers if the transition is too sharp. Since your couplers on locomotives stick out quite a bit beyond the pivot point of the trucks, what will happen on a sharp transition is that the couplers can either dip or rise enough to actually uncouple the cars from it. If nothing else, that can be a guide to whether your transition is gradual enough.
 
Very good point. My layout is all open grid with 1x4 risers to plywood sub roadbed. The transition is more or less automatic. No real need to have to figure out a transition. For the most part it will be very gentle. I never had any problems with cars uncoupling, but modeling the transition era, 50 foot freight cars were the largest and longest for the most part. I also super elevated all of my curves, but this is another subject.
 
as for the pulling power of locos on a grade, here is a video that I shot on my layout about 18 months ago. At the 3:30 mark train starts up a long 2% grade with two locos and an assorted freight train of 37 loads. Eventually, the entire train is in the grade. On your layout, you may get about 10 at the most in your grade. The locos are an Intermountain ES44AC on the lead and a Broadway Limited AC6000.

I could run them much faster up the grade but I like to run em at a prototypical speed.

[video=youtube;lIQ2p0C08ms]https://www.youtube.com/watch?v=lIQ2p0C08ms[/video]
 
Great stuff Ken and a good illustration of the transition back to level at the top. (off-subject)Nice dismantling of the front loader and scraper too to enhance the loads.
 
wombat457 said:
Jim,

Just so you know, the "formula" for working out your grade is an easy one and based on a total length of 100", ie:

A vertical of 1" over a horizontal of 100" = a 1% grade
A vertical of 2" over a horizontal of 100" = a 2% grade and so on.

Therefore, a vertical of 1/2" over 50" horizontal = 1%
1/4" vertical over 25" horizontal = 1%
1/4" vertical over 12.5" horizontal = 2%
Click to expand...
Tony's such a smart guy.:cool:
 
montanan said:
Very good point. My layout is all open grid with 1x4 risers to plywood sub roadbed. The transition is more or less automatic. No real need to have to figure out a transition. For the most part it will be very gentle. I never had any problems with cars uncoupling, but modeling the transition era, 50 foot freight cars were the largest and longest for the most part. I also super elevated all of my curves, but this is another subject.
Click to expand...
Don't you love the way open grid and raising the railbed works? Up a bit here , eyeball it , up a bit down the line , eye ball it, fasten all the risers in between and call it done.
 
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