Maximum Short-Run Grades

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Brakeman Hal

Well-Known Member
Would a light freight train with a GP35 on the point be over-taxed on a 3.6% grade over 1/4 scale mile? (10" rise over 27.5 feet in O Scale)
Hal
 

dave1905

Well-Known Member
Depends on what you mean by "light"? Does the train have a running start or are you starting on the grade from a stop? Are you talking about a prototype or model train?

Really rough calculation for powering a prototype train at speed was the train needed 1 horsepower/trailing ton per percent of grade. 2500 hp/3.6% = about 700 tons. At drag freight ratings of 1/2 hp/tt, that's still only 1300-1400 tons (10-12 loaded 100 ton cars). Once again at speed, and that anticipates a long grade. A 2000 hp SD38 hump engine can shove a 7000 ton train up a hump lead at 4 mph.
 
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Brakeman Hal

Well-Known Member
This is an O-Scale 2-Rail 1/48 scale model. The engine weighs 5 pounds.

I'm starting from a level track.

The consist is 6 freight cars lightly loaded.

Hal
 

Brakeman Hal

Well-Known Member
I have a 2% grade on my present layout, but I think I'm going to forget the plan for another one on my 130-foot folded dogbone. I can't even detect a slowdown when my freight train goes into the grade.

Hal
 

KB02

Well-Known Member
There is a great video online that I will try to find a post here of a local Vermont railroad that operates a bunch of switchbacks to get to a quarry. I think they said some of the grade approach 5%!!!

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Found it!

Found another video, too, where it said the max grade was one section of 8% 😲

So I'm thinking your 3.6% should be just fine. :)
 
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Brakeman Hal

Well-Known Member
Thanks, KB02, but I think I'll leave my layout the way it dang well is!

(Father was a Fireman on Pennsy Consolidations and Mikados in the 1940s...he would sometimes take me to work with him when there was no school and he had yard duty...quite a thrill for a 6 to 8-year-old West Virginia boy, spending the day in the cab of an 0-6-0 switcher!)

Brakeman Hal, age 84
 

Rico

BN Modeller
Ah... so this was yet another cry for help with one of your (patent pending) “naw I’m good just the way I am” responses.
You'll have to start adding “Bazinga!” to the postings Hal. ;)
 




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