So looks like I’m going about half % per longest car or less transition. Yeah prefer conservative.
Think maybe a broad turnout may be ok at the 1/2 percent tail end being so conservative?
Personally, I wouldn’t put a turnout in the middle of any change in grade*. That’s where I am conservative. If you are talking about right at the end of the vertical transition, I’d personally still want a bit of space between the end of the transition and the turnout.
Byron
- RG knows this, but just for the record, turnouts are fine in the middle of a grade; it’s just where grades are changing that it can be a problem.
I found that if I lower the track being crossed over, I can get the necessary clearance with a more gradual incline. I have a 7" difference in height but lowered the lower track by 1" gradually where the upper track crossed over. I had 25’ feet to create my incline. Worked great!
I agree with Byron that you’re being overly conservative. You can easily calculate what is acceptable for any car.
Consider a worst-case where the grade starts immediately with no vertical curve. If car 1 has his back wheels barely on the grade, and car 2 is on level track, the couplers will be at maximum deflection. Being in N-scale I don’t have one on hand to measure, but as I recall the face of an HO coupler is about 1/8". Since grade = rise/run, take the coupler face as rise and the distance from the coupler face to the truck bolster as run (3" for a long car maybe?) and we see that .125/3 = 4.17% required to force a decoupling. I think limiting the grade change to less than 1/4 of that would work 99% of the time. So the 1% per car length that Byron suggested works out pretty well.
I don’t mind doing such calculations when necessary, but the method I used, as outlined earlier, worked partially due to the 3/4" plywood roadbed, which wasn’t forced into an abrupt rise (or drop at the top).
It also worked because I had a pre-determined amount of rise necessary (15.5"), and a set length (45’) in which to accomplish it.
Because the 45’ is laid out over a number of curves of varying radii, the risers could not be spaced at regular intervals.
However, I did have the track laid and fastened to the 3/4" plywood roadbed for the entire climb, so simply created a 10’ long train to use as a measuring device, which yielded both the total length of the grade and a method to easily find its mid-point.
Once the riser was added at the mid-point, with a height equal to half of the total required, the rest was simply common sense, as the stiff-ish plywood formed very acceptable vertical easements at both the bottom and top of the grade. All I needed to do was add risers without altering the grade.
I also added superelevation in the same manner, using the 10’ train as a measuring device to determine the mid-point of each of the curves.
All of the fastened-in-place risers were marked with a pencil line denoting the top of each open-grid crossmember to which they were attached, then the screws holding them in place were removed.
Next, the riser closest to the mid-point of each curve was lifted so that its pencil line was aligned with the top of its respective crossmember. The bottom of that riser was then pushed towards the outside of the curve, until the look of the train sitting atop the curve seemed to be realistically superelevated.
The riser was then re-screwed into its new position, with only the inner end of the line matching the top of its riser.
All of the other risers within the curve had also been deflected outwards, to diminishing degrees, as they moved away from the mid-point,