Mmmmm steep gradients........ I have much experience with this little feature.
They do cause interesting challenges to be highlighted
I have about a 3ft rise over around 40ft which has a max 1:10 section (under a bush) in the middle. People do not believe me until they visit and usually say something along the lines ... WT*
This slope is due to the 'interesting' garden topography and a cutting or raising the other side of the layout etc was not a possibility (tree roots, stepped access onto lawn etc etc)).
I had thought about a helix as the ideal solution but it would mean that the lawn would be rendered out of action let alone getting across it to the decking, pond etc etc.
Having said this.... I did add a small spiral in an area where I had cleared a lot of bushes. I did this to add a bridge and a trestle for visual interest. Unfortunately the helix curve is a bit tight and the gradient is a bit steep (the helix rises 11 inches over the radius using a mix of R2 and R3) so a sumpter mallet can only pull a max of three cars unaided.
Although locos can make it up the main loop gradient on their own, it is only the geared ones like Shays, Heislers and Climaxes that can pull a decent length train without help.
So I have overcame it, first with double/triple or even quad headers and then later by also customising rolling stock by putting 'invisible' motor blocks in things like Stock cars, box cars and passenger cars.
It is interesting that in reality it is not the going up a slope that is the real problem (as applying extra oomph is the solution) but the coming down can be problematic as the force exerted by the weight of the rolling stock on couplings etc can cause derailments, especially if there is a curve after the downward gradient.
I have had to test my rolling stock and found that 'the lighter cars (wagons) had to be at the rear as they would 'buck off' the track at the curve.
If your locos are not free running (ie you cannot push them along the track without the wheels slipping) then putting one at the rear or middle of a train can act as extra 'muscle' and as a 'brake' (this is used in the real world). Diesel and electric models are the best as steamers tend to have pretty free running gearing (try pushing an LGB Mogul to see this), and they will just 'run away' down the slope.
So in a nutshell, if you are going to have to have a fairly rigorous incline, then do what has already been mentioned, no points near to either end of the slope, make the curvature as wide as possible, experiment with multiple loco power placement and test the reliability of rollingstock and you will be fine. .....
Trust me, I have been doing (what people told me) was the impossible for the last 10 years.
I have learned to add weight to cars that might cause problems and I have not broken any gearboxes ..... yet
This shows the max gradient under the bush the RS3 diesel had one 'invisible' helper
At the summit. The GP9 had one 'invisible' helper
The Sumpter Mallet approaching the 'manufactured' spiral
Sumpter mallet has done the helix and is about to clear under the bridge.
Good evening,
