building inclines

[rookie]

I was wanting to have a bridge at the top of a hill for my ho scale train. Do you have to use flexible track or can you angle the bachmann track up enough?

[ABC]

No, you can rig it up to work with the E-Z Track, the more gradual the incline the easier it would be to start. Woodland Scenics makes grade starters, or you can make your own.

[TrainArts]

Yeah, be careful about pier sets, they often rise too quickly and fall too quickly, causing slippage on the way up, decoupling at the top, and on the way down the cars (if you have several or more) can push too much on the locomotive, jamming up cheap gears.

I tried the Bachmann 18-piece pier set and it really didn't work out at all.

But to chime in on your basic question, yes, you can use sections of track, just keep the grade limited. I had Kato Unitrack N scale with many grades and it worked fine.

[Jim Banner]

You already know about and use horizontal curves on your track layout.  These are the "corners" the train goes around.  Now it is time to learn about and use vertical curves.  Transitions from flat to slope and slope back to flat should not be abrupt like a misaligned track joint.  The transitions should be a gentle curve.  How gentle?  The one I laid out this morning has a radius of 187.5 inches ( about 15 feet.)  Think of a plumb bob on a string 187.5 inches long.  When it is hanging straight down above a horizontal surface, it is exactly at a right angle to the surface.  If the string and plumb bob are the radius of a circle, the point of the plumb bob will be exactly at the point where that circle is tangent to the horizontal surface.   If you move the plumb bob 13 inches along a line that lays on the flat surface and passes through the point of tangency, it will point to where the circle is tangent to a line rising above horizontal surface at a rate of 4" in 39 pi inches or about  3.5367%.  The line on the horizontal surface is the centerline of my horizontal track, the curving line is the transition, and the straight rising line is the centerline of the sloped track. 

The radius of 187.5 inches was determined this way.  The front and rear drive axles of the 2-6-0's I want to run up this hill are 3 inches apart.  When they are on the transition curve, I don't want the rail head to drop away from the center drivers by more than 1/4 of the flange height (assuming the wheels and frame are perfectly rigid.)  That would be .006 inches.  Two points 3 inches apart and a third point in between the two but offset .006 inches defines a circle 375 inches in diameter or 187.5 inches radius.

The ceiling in my shop is only 8 feet high.  I could have used a horizontal trammel 187.5" long and tipped the layout on its side, but instead laid the circle out in a CAD program and measured the rise from horizontal every inch for 13 inches.  These measurements were easy to plot on the wood supporting the plywood road bed.  Would I go to all this trouble every time I want a smooth transition?  Maybe not, but in this case, the vertical transition curve is smack in the middle of an 18" radius horizontal curve and I am breaking the third law of successful track layout - never put a vertical curve in a horizontal curve.  Wish me luck and stand by to post my bail.

Jim

[Acceletracker]

Good Luck Jim. 

[rookie]

Jim, i only have currently about7 feet to work with. With out making my head hurt could you estimate how much rise to the inch i could do? I am pretty good with simple math but not in your league with track building  or whatever it was you were saying to me. Thanks for your reply. David                                                                                                                       

[Heave]

3% will get up and over 4 inches in about a 12 foot run.

A 4% rise will clear 4 inches in about 8 feet.

If a engine can pull 10 cars level, it will pull 8 on 2%, 5 or so on 3 and less than that on 4% I consider 4% the upper limit.

Woodland scenics is my way of building inclines. My head hurts too much otherwise.

[jward]

another way of looking at your railroad, is to compare it to a house. most beginner's layouts have only one level, like a ranch house. adding an up and over section makes it a two story house.

your best bet may be to build your railroad like a split level house. the main level, instead of being at base level, would be elevated 1 1/2" to 2" above the base level. where you want an over and under section, instead of trying to get to 3" or 4" in elevation over the distance of 7 feet you mentioned, you'd drop one line to base level, and raise the other line to 3-4".....by splitting the grade between the two lines you can effectively reduce the steepness of the grade by half.

btw, the 3 or 4" figures i came up with are dependent on how you will cross one track over the other. if you intend to use a bridge, the bottom of the bridge must be at least 3" above the rails of the track below. if you'd like to have the lower level disappear into a tunnel, and have your roadbed (trackboard) carry to upper track over the lower one, you'll probably want to have your upper line at 4" to ensure enough clearance for the trackboard over the lower track.

as was mentioned in a previous post, woodland scenics makes inclines in 2%, 3%, and 4% grades, they also make risers which will elevate your track above the baseboard by a set elevation. i think they have 1/2", 1" and 2" risers.