Larry,
Curves can really add a lot of binding when climbing a grade. On the prototype, a good rule of thumb is to add .05% compensation for each degree of cure. This a 22" radius curve(40 degrees) will add about 2% on to of the actual vertical grade. Your vertical grade is 1/120 =
2.5%, plus the 2% compensation = 4.5% - pretty steep! With our soft metal n/s rail, the actual binding may be worse that the above formula states!Jim Bernier
"larry l." wrote:
My layout requires a grade that rises 3 inches in 120 inches of
> 22 inch radiuscurves. However, none of the model steam
> locomotives I own will pull more than 4 cars up the grades.
> I have a docksider and a 'teakettle' which when coupled together,
> will pull seven cars. However a new Bachmann Prairie 2-6-2
> will hardly pull itself, much less any consist.
>
> I imagine that the problem connected with the load imposed by
> the lateral friction on the curves, but I see lots of layouts
> with higher grades on curves.
>
> Doesn anyone know of a reference source which dealw with
> grades on curves,and does anyone have a solution?
> Thanks,
> Larry