Maximum Gradient

[Loco722]

Hello there!

I'm in the process of designing a track plan for a new layout with a twice around oval track design.

After doing some research on the internet it seems like the maximum acceptable gradient for HO scale model railroads is 4%.

I'm modeling a fictitious branch line where the trains will be limited to only one locomotive (only diesels) and a maximum of 4 50ft box cars and a caboose.

The table is a 4 by 8ft table. All the curves will be 18'' radius and all gradients 4%.

Any opinions/comments/advice are most welcome .

Loco722.

[ebtbob]

Good Morning,

     First of all,  you should be able to get away with a 3% grade on a 4x8.
Also,  with a twice around oval,   some of your curves could be 22in radius,  depending on your plan.
      4% is a VERY steep grade and I would not recommend it.   Also,  consider on using the Woodland Scenics styrofoam risers and inclines to give you a consistant rise and fall of the trackage.
       

[jward]

as you guessed, 4% is about the maximum recommended grade. but 3% has a very big advantage in looking at a track plan in that it works out to about 1/4" rise for each full section of track. so if you want an up and over type plan where one track crosses above another on a bridge, you will need a minimum of 12 sections of track between the bridge and the lower level track....

that said, if you have a longer run between your highest elevation and the lowest, you can lessen the grade and your locomotives will pull more up the grades.

on my own layout, the grades will be between 3 and 4 % on those same 18" radius curves.

[Robertj668]

Loco722
On our layout we played around with a 4% grade.  With one engine and about 6 cars the diesel did not make it up all that well.  When we did 2 engines we could do about 8 or 9.
Probably the main reason we have not set the final track plans is that we are working with now a 3 and a 2.

If your train can do and you are happy, enough said! Do it and have fun!

Enjoy

Robert

[jettrainfan]

ummm.... banker/helper?

[Loco722]

Hello there!

Thanks for the input guys !

But I seemed to have forgotten to mention a few things about my new layout.

Firstly its an over and under twice around design.

Secondly, the tracks I'm using come only with a few types of track sections. (I'm using Life-like Power-loc tracks).

The latter mentioned is what has really made me choose 4% gradients on my layout .

I did go thru the track plan (still on paper) and did notice I maybe able to reduce this to about 3.25% using 12 section of track like Jward mentioned.

However the clearance between the top of the tallest box car I have from the roof of the planned tunnels will be 1/2 on inch roughly 43 scale inches.

Would this really be enough I wonder ?

Thanks again!

Loco722

[Jim Banner]

A miss is as good as a mile.  Any clearance at all is enough.  Just as long as you don't go out and buy some taller cars.

One trick that can give you an extra 1/4" of clearance (or let you reduce the grade a bit more) is to remove the base from your track where it goes over the track below, or at least cut away that portion of the base.  If the lower track is in a tunnel below the upper track, you might want to put a layer of thin cardboard beneath the upper track just to keep any ballast from falling through.

On my own H0 layout, I have a helix with a 3-1/2 % grade.  It limits some locomotives to 6 or 8 cars.  Beyond that, double heading or a pusher is required.  As far as I am concerned, that just adds to the fun.  If you use DCC and have a pusher with a Kadee or similar coupler permanently glued open, you can push the train up the hill and then drop off the pusher without ever stopping or having to uncouple.

Jim

[jward]

i have a high cube 40' boxcar that i use for clearance tests. that, or a 50 foot flat with truck trailer will be the tallest cars you are likely to run, anything taller will be too long for your curves.

in the past, i have deviated from the "standard" 3 inch clearances by cutting down the height of tunnel portals so that the high cube boxcars barely fit under them. it gives the look of certain low clearance routes in the east where taller cars were not permitted.

[pdlethbridge]

This won't apply here but logging Railroads had very steep switch backs that were as steep as 10%using shays and climax's

[ebtnut]

You might try and split the difference and try 3.5%.  A good diesel should be able to handle 4 or 5 cars on that grade. 

[Jhanecker2]

Question ? Does anybody know what the gradient is when using the piers from the Bachhmann expansion set ?  John II

[jward]

i am not familiar with this set, but i do know that the atlas pier set, used one pier per section of track, is approximately a 3% grade. i suspect the bachmann set is the same.

[Loco722]

Hello there!

Thanks for the input guys.

I have re drawn the track plan and have managed to reduce the gradients to little more than 3% (3.05% to be precise) !

Of course even this plan could also change, who knows!

Thanks for the input once again !
   

Loco722.