Model Railroading > A steep 4 x 8 loop grade?

I'm pondering a possibility within a 4 x 8 ft. track plan. In a previous 4 x 8 ft. I pulled off an overunder that clears double stacks using about a 82 inch length for the grade, which looks like a 3.96% percent grade. That was split between a mainline rise and a branch line fall, the latter being steeper, so probably more like 5%, but it still worked.

Now I would like to see if I could pull off an over/under where the grade largely exists within a full circle. My existing 21" (or so) radius curve runs about 75 inches to go 180 degree within the 4 x 8 foot space. So a full circle would run about 150 inches, and I would only need 3 inches of clearance or less for smaller, shorter european type cars. I see that might be a 2% grade, which sounds possible with tiny trains of short cars.

Has anyone seen a published trackplan that uses such a tight loop for the grade? When I looked all I found was a very small image of an early John Allen railroad.

This doesn't need to look that realistic, it just needs to work.

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Remember to include the track and supporting surface in the calculation. It gets tricky when folks want to use heavy plywood and sound deadening, or preformed track base like Kato or Bachman.

I did this many years ago with a hidden storage area under the top sheet of plywood. Took a little finagle-ing but it worked. Up ramp was in middle and down ramp was on edge. Of course you are not running huge coal drags in loops but for a short line OP it's fine.

Yeah, this is going to be a Bachmann China DF4B that is likely able to do tight radius turns despite being 6-axle, and 3-4 40' European frieght cars. I'd be making it using flex track on foam.

Interesting way to show an interesting model. There had been a website that demonstrated small exhibition style set-ups, Z-guage on a large hat for example.

The classic was the MR article a number of years ago building an N-Scale Layout under glass in a coffee table, right up front in the living room.

When I had my "O" Gage layout I had a helix and the base cage to hold the helix for the elevation loop measured twelve feet square. It took me quite a time to construct and it was double track and kept the grade at just under 2%. Of course I had the room but building it was a challenge but I enjoyed every minute of it and it worked beautifully.

Happy holidays to all.
Jim
​Hatboro, PA

I am trying to do something similar with a 6x10' Harpers Ferry track plan from John Armstrong.  As stated, the track substrate is the real obstacle.

You can extend the lower track's circle to the left a foot or so to decrease the grade.

Here are two plans from 101 Track Plans, by Linn Westcott, with ideas,  both in less than 4 x 8 ft. The second is a modification of the original John Allen layout, and has gentler grades.

Have fun!

-John



Edited 1 time(s). Last edit at 12/03/16 06:47 by LarryDoyle.

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