First, grade is independent of scale. A rise of say 1/4" per foot is the
same grade in O scale as it is in N scale.
Next, this sounds like a cliche, but it all depends... A curved grade pulls
harder than a straight one, so you sould have to account for that. Your
train length and locomotives would be a good determining factor as well.
How high do you "need" to go? If you are doing a cross-over, I'd guess
something around 2" would be enough clearance.
I'd set up a piece of track on an inclined board and do some test runs. The
1/4" per foot I mentioned before would be about 2%; a half inch per foot
would be around 4%. I would think that anything much steeper than that
would look "toy-like" UNLESS you were modeling a rustic lumbering line. In
that case, steeper grades would usually be the norm. Like I said, it all
One other thing that you want to consider when creating your grades...
transition. When I built my layout, I didn't account for this and had some
real troubles. Here's what happens... if you don't allow for transitions,
your locomotive is moving along then the front end suddenly kicks up onto
the grade. This causes the back end to drop and if the couplers of your
locomotive stick out some distance, they can drop far enough to cause the
car to uncouple. The same thing in reverse happens at the top of the
untransitioned grade. The locomotive tops the hill and the rear end pops
up, again, possibly enough for the cars to come uncoupled. So make sure
that your inclines are flowed into and out of smoothly. If at all possible,
try not to have a track joint at either the beginning or the end of the
incline. Flex track comes in real handy here.
If you are having trouble understanding the transition I'm talking about,
think of it in terms of driving your car onto an incline... if the incline
starts abruptly, the front of your car goes up and the back end drops down,
sometimes dragging. That is about the best I can describe it w/o being able
to attach a drawing.
So get out those cars & locomotives and see what works well for you. Good
This is like asking "How long is a piece of string?"
Railroads ran with grades as steep as 1 in 19 to less than 1 in 1000,
Home of the Great Eastern Railway
Not to put down the tables but these sort of things remind me if a story at
the Canadian Railway Museum, way back when it was starting.
The volunteers were laying their first lengths of track. The CPR had staked
the centre line of the curve and the volunteers had laid the ties out over
the sub ballast and were now placing the rails onto the ties. The problem
was, how do you bend the rail to the correct curve to fit on the ties?
The guys were business men, university students, lawyers, doctors, tradesmen
etc.., etc., and none of them had any railroad experience. So here they
were puzzling over how you bend the rail to the correct curvature. Some of
the more mathematically inclined were try into calculate curves and other
mathematical formulae using their slide rules. While this was going on,
another new volunteer showed up. He was an older fella, in his mid 50s with
the look of a working man who'd spent all his working life outdoors. He
asked what they were doing and they explained how they were having trouble
figuring out how to calculate the curve in the rail so that it would hold
it's position on the ties so they could spike it down.
He said, "Like this" as he walked over to the end to the rail, grasped it
with both hands, and slewed it into position on the ties. He was the
Montreal Terminal track supervisor for CPR.
The same can be said of the vertical curve at the top and bottom of the
grade. The road bed will form a suitable curve all on it's own thanks to
the natural flexing of the plywood. Let it form it's own curve and then
place risers under the naturally forming curve, do not force it.
Home of the Great Eastern Railway
Wouldn't work with spline construction or the foam risers a popular
scenery material supplier sells though. The layout builder would be
dependent on fabricating a reduced grade for a short distance with the
spline shape or foam risers. There would be some guidance from the track
if flex track was being used, but there would be some challenge avoiding
sudden grade changes with old fashioned O/027 sections or the roadbed
track that is becoming popular in many scales.
It's not too much of a problem at the bottom of the curve. As long as
you allow the cork (or foam) roadbed to form it's own vertical curve you
will not have the abrupt transition.
It is much more of a problem at the top of the riser. The riser ends
with an abrupt angle. The only solution I have thought of is to trim a
small amount off of the top of the last few riser sections and then
stretch this section out about 1/3 more than its natural spacing. This
should allow the cork roadbed to form a smooth curve over the transition.
Depending on the material that you used, you could also just remove the
abrupt change at the top... I'm thinging that if you were to use the foam
"ramps," you could simply take a Surform to the joint and round it off.
Harder materials might sand pretty well. The good thing is that you
wouldn't have to remove all that much to get the shape you wanted. Like I
suggested earlier, the IDEAL solution would be for the manufacturer to offer
a transition piece at the begenning & end of each set. But then that would
deprive us of the aggrivation wouldn't it??!?
Good point, but in my case, I used Woodland Scenic's risers & inclines. In
retrospect, it would have been nice if they would have allowed for this by
making the first & last section in each ramp half the incline of what the
rest were. In other words, I used 2% ones; if the first piece & last piece
were 1%, it would have helped a lot, especially for new users (and older
users like me!). Then I also had the fatal error of having a couple of
places where there were rail joints at or near the transition points.
Again, having never done this, I didn't realize the problems until I started
running test trains. I don't know what the proper measurements would be but
I'd guess that a section of 36" flex track over a 1% transition to a 2%
incline would have been about right.
To make matters worse, the vertical movement varies based on the particular
locomotive. One that really gives me fits is an Atlas RS unit that seems to
have a relatively short wheelbase and a little longer than usual overhang at
the end. That really creates the vertical movement of the coupler. : (
Ain't this hobby fun??!?
Excellent warning against overthinking the problem. According to an
ancient book, MODEL RAILROAD ENGINEERING, which is full of neat
if dubious little anecdotes (as well as a rare application of English-
style MBS to model railroads) the usual way to lay out horizontal
was to stake out the curve at intermittent points using Searles'
tables, spike them to the ties, then smooth them out with repeated runs
by 'a fairly heavy locomotive' before ballasting. Anybody care to
this as real late-30s practice?
Overthinking the problem...not uncommon in model railroading!
I suggest to the OP that he make a test track, and try running his
up various grades. Spike down a minimum-radius oval, and tilt the
to see what happens. Make a long straight on a 2x4 and see what load
they can pull at several different inclinations.
President, the still-boxed-away Sparta Railroad
First, in any scale, grade is rise/run x 100, which gives you the
"percent grade." thus, 1% means 1 foot in 100 feet, or 1/4" in 100 x
1/4", which is 24.5", or about 1/8th of inch per foot.
Second, in any scale, including full size, grade affects how much the
loco can haul, and the effect is drastic. Real railroads try to keep
grades around 1% or less if possible, but even a 1% grade will reduce
the hauling capacity of a loco by 30 to 50%. That's right: _half_ as
much as on the level.
As for N-scale: if the locos have traction tires, you can easily go to
about four percent (ie, 1/2" per foot) and even more. If they don't have
traction tires, stay at 2% or less if possible (about 1/4" per foot.)
You need about 1-1/2" clearance from railhead to overhead obstruction.
Dan Merkel's answer also has good advice.
When I built my small 2x4 N-scale layout, I bought some foam risers and
inclines from Woodland Scenics and experimented with the inclines.
On a 2x4 layout, the loco would barely pull itself up a one inch incline in
that short of a distance. It couldn't maintain traction and would spin the
wheels all the way up.To make matters worse, when it started down the
incline, it was like watching a roller coaster.
I finally decided that half an inch was as good as it was going to get. The
loco pulls it nicely and it doesn't have the roller coaster effect. It isn't
much, but it at least gives variety to the terrain.
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