I am getting started on an ho scale layout, and I just learned about the ‘bowl’ for rail yards, and I want to do that. My question is, do I have to worry about the incline from the mainline, which is 3mm high I believe, and then the cork sheet, which is a little bit shorter, maybe 1mm? So with that, do I have to worry about any drop or can I just set the track down with no long piece for an incline to transition? Thank you.
I think you intend to have most of your yard ladder and related tracks at a slightly lower altitude relative to your mains passing nearby? That’s fine, and I do that to myself to an extent. The best thing to do is to sand around the sharpest part of the drop between cork levels, first with short strokes to rub down the high lip a bit and then broaden the strokes to make it a nice long and gentle slope. It won’t take much, so if you are counting beyond 20 strokes, you are probably creating a gully where you don’t want one.
You’ll need no special pieces if you do this patiently and slowly to ensure you don’t remove material you don’t have to…or shouldn’t. One you have the slope, just place your flex track or similar track over your slope so that the ends mate up with other ends outside of the slope area. That way, no joints will be near the slope and you can pin the tracks and ties, or adhere them, so that they conform to that gentle dip into your yard.
More skilled and advance modellers won’t be deterred by having to place joiners somewhere along a transition curve, but it’s best for newcomers to the hobby to avoid doing that just now until you have more experience fashioning the curves and laying track.
3 mm is about 1/8 inch. A wooden wedge from a lumber yard or hardware store works just about perfect for this. They’re about 1 1/2 inch x 6 inch and a bundle of them costs a dollar or two.
The average a cedar shingle will transition from feathered tip to that 1/8" needed is only about 4-5" in length. You can use one, however the tranition may be too short. Sanding down the cork to drop to the thinner cork used for the yard will give you the better control of the slight easing for the drop. this can be done in as little as 8-10" or much nore gradual if the lead allows. Your roadbed doesn’t need to be that perfect as you can allow the track to take the shape w/o forcing the rails to unwanted or irregular elevation. Any voids under the ties can be filled w/ sand or ballast glued for temparary track support. later when ballasted the entire lead will be secured. Of coarse testing the transition to suit perfect trackwork, the track can always be adjusted and reglued until satisfied.
I agree with Bob that a standard wood wedge is likely too short for a vertical transition.
What I do is lay the taller cork or whatever as far as possible to where the shorter material starts. I typically use cork, too, but this also works with homasote or luaun, etc. I use a Stanley Surform to shape the cork, wearing down the ramp until it matches the lower stuff and forms a smooth vertical curve up to the higher.
For longer transitions, I use a bench-top belt sander to put a taper in the cork. Apply a piece of aluminum duct tape to the back, then carefully press the cork to the sanding belt. It goes very quickly, so keep checking the ramp you’re making to not over do it.
…or use flex track and make the transistion whatever you want, then ballast the track. When you glue the ballast in place it will support the flex track in whatever transition you have set.
True, this is a method that I see many of our experienced members here, will use. This is helpful especially for tranitions close to turnouts (moreso if a turnout is on and incline or has approaching superelevation}. The trackwork can be repeatedly tested and track shimmed as needed before securing w/ some glued sand or ballast. Those spots usually are the most troublesome and can cause derailments.