Grade (rise/run) for HO bridges

[Anonymous]

I am planning a 4x8 layout in HO scale, and was wondering what would be the most effecient rise-over-run or grade ratio is for inclines leading to bridges. Thankx.

[Anonymous]

I would not want to exceed 2% (2 inches per 100 inches) but that is unlikely in a 4 x 8 so I recommend that you get it as close to 2% as possible. If your grade exceeds 5%, forget about hauling freight. I know many locos will climb the grade but it is more of a compromise than I would accept.

That's what I recommend but you can do whatever you think is best, of course.

Good Luck - Ed

[Anonymous]

Given the limited run length on a 4x8, your best bet is to raise the upper track a maximum of 2 to 2 1/2 per cent, and lower the lower track about the same.This means the "base" level can't be on a fixed plywood tabletop surface. Best to either use open-grid or L-girder benchwork, and mount the roadbed on risers.Either that or use one of the newer styrofoam -base methods. There are many articles and books in the model press covering these methods.You will have a much better approach to scenery using one of the above methods. Good luck and regards / Mike

[Anonymous]

He could still use plywood tabletop if he uses the old cookie cutter method and drops the lower track by sawing on each side of the track outline and then building the upper track up over it. But I agree the open grid is best. If he had chosen N Scale he wouldn't have to rise so much for a figure 8, (2 inches instead of 3 or more)and the 4x8 size would have been plenty big. Anyway, good luck. -Ole Greenriver

[Anonymous]

It's going to be tough, because I was able to get mine working OK, but mine's an 8X9, not a 4X8. I used the cookie cutter approach (see previous post) where I dropped the lower track and raised the upper track the same amount to get the over/under. I run steam equipment, so I cheated on the clearance, no double-stacks allowed! Even still, it's tough getting up the grades with a long train of 18 40-foot cars. You will probably run a shorter train, so that's good. Do whatever you can to make the grade as gentle as possible, within your limits. Also, Try to do 5X8 or something just a LITTLE larger, even if you have to overlap 6" of bare plywood over the edge of the frame, like I do. It works, and things are less crowded. Research your track plan, try a folded dogbone plan to get the most distance to your incline... check out Atlas' track plans, then modify one to best suit your preference.