Can you start a grade change on a curve or are you building in problems? Should you wait till the curve is completed and returns to straight track and then start the grade change? The curves are ho 36" or 30" radius.
I have grade changes on curves as tight as 18 inch radius (HO).
They work fine for short cars, but by passenger stock can’t handle it. The 30 inch radius curves work fine, even when changing grades.
As long as you don’t make the transition too abrupt, changing grade on a curve is no different from changing grade on a tangent. I have a 2% grade that transitions to level at the bottom, with the theoretical point of change right in the middle of a 610mm radius curve (24" for the metrically challenged.) The grade transition is about 800mm long. None of my rolling stock, from short wagons to long locos, passenger cars and auto racks, have had any problems with it.
(That same grade goes over a summit, from 2% up to 2% down, through the transition and curve of a 670mm radius horseshoe at the end of the peninsula.)
Chuck (modeling Central Japan in September, 1964)
Are you sure you are not mixing up Radius and Diameter?
How wide is your benchwork? For 36" Radius, you will need more than 7’ wide to make a turn.
If you are talking radius, then, as mentioned above, the trouble always arrives in the vertical transition, no the grade itself (unless you are going above 3% or so).
If you are talking diameter, then a vertical change will have dire performance results with your locomotives because of the very tight radius.
David B
Speaking from experience, a grade change on a curve, especially in tight radius (18-22-24) is not a good idea if you’re running ridged frame locos like some of the big steamers out there. I was a steam freak in my youth and several occasions where a locos wheels rise off the rails coming off a curved grade and derail. These weren’t badly done grades either. A three inch rise in twelve feet.
Yes the turns are 36" radius. We were looking at a 4" change over 18 feet. to get that length we had to start the level change mid turn.
im using woodland scenics’ 3% incline system on my 4x8 layout to make a 4 1/2" rise via an S-curve located inside the main loop, using 18" minimum radius curves. As long as you aren’t planning on using any giant articulateds hauling long trains of like, 4-bay hoppers, you should be fine. even 6 axle locos work on 18" curves
Woofda, I have a 30" radius curve that raises 4" in 16 1/2’, a 2% grade. The transition is smooth. I am using a cookie cutter type of sub-roadbed that is cut in a sheet of 1/2" plywood that is also part of the surrounding landscape. It makes the transition much smoother since the plywood and sub-roadbed are not detached from each other.
Bill
I have some trains that don’t do well on 18" radius curves.
I have been moderately successful at riping up 18" and replacing them with 22", but It wasn’t possible everywhere. Once I became aware of the problem, all NEW construction was 30" or more.
I have both on my laout. No problems witheither of them. Good trackwork is the answer.
HUH???
Hi,
I sure agree with most of the previous postings, but gotta add my “FWIW”…
My layout has two significant grades (2 percent) and I consciously started them on straight trackage. Beginning grades on a curve (the broader, the easier) is typically adding in a derailment potential and a reduction of loco hauling power at that point.
However, it certainly can be done and done well. I would tend to use the “cookie cutter” method of benchwork, have a nice smooth vertical transition to the ruling grade, and make sure that there is no track joint in that transition (use flex track).
ENJOY,
Mobilman44
6’ foot circle with 6" clearance on each side…
My mistake! I thought I saw the word `more’ in davidmbedard’s response. Gonna have to learn to read more carefully!
Your problems are correlate with radius and car length and transition curve of the grade. If all is gentle you will have no problems. You need easements! It’s the same with camber of the outer rail in curves.
Wolfgang
A change of nearly 2 percent in grade on a 36-inch radius curve shouldn’t cause problems if the vertical curve is sufficient. A transition of at least three feet should be enough. You will need to lengthen the distance of the grade or increase the grade steepness to compensate for the transition.
Mark