I notice that authors talk about making yard tracks basically flat to the base while main lines are ballasted and elevated above the landscape.
My question is how/where to make that transition? I assume that one does not slant down the turnout so I am wondering how folks handle that maybe 1/4-1/2" change in elevation into the yard?
I suppose I could make all my yard tracks slant down like a humpyard but I really don't like that idea either.
The yard body tracks are basically level, only sloping up to meet the (slightly) higher mainline tracks at the ends toward the mainline connection. In HO, The difference can be as little as 1/8 inch. 1/2 inch would be gross overkill in any scale smaller than G.
In the prototype world, there are two reasons for this. One is that the mainline was probably reballasted and re-tamped many times over the years, while the yard trackage got much less attention. The other is to discourage unwatched freight cars from embarking on unplanned journeys down the main. Most cars don't roll uphill from a standing start.
Most prototype yards are double-ended, and that little slope can be found at both ends. That's why the body tracks are frequently referred to as, "The Bowl."
Chuck (modeling Central Japan in September, 1964)
jake9 wrote: I notice that authors talk about making yard tracks basically flat to the base while main lines are ballasted and elevated above the landscape.
The reason for the differential is drainage. Main tracks are built higher than yard tracks from the beginning in most places because the standards for the amount of ballast under the track is different for a lower speed, lower tonnage siding or yard track than for a higher speed, higher tonnage main track. The main track is normally higher than the surrounding area to promote drainage. Side tracks and yards are normally not as critical so do not need to be lifted up as high. Railroads are willing to spend the money to raise a 60 mph main line high to keep it fast and open, but don't necessarily want to spend the money to raise acres of 10 mph yard tracks. There is a certain amount of build up due to ballast raises over the years, but the basic differential was there when the tracks were built. The railroads can't always keep raising the tracks either. They have to keep the top of rail fairly constant or they will get in trouble at overpasses, bridges, crossings, road crossings, defect detector installations, etc.
Normally the main track will continue elevated through the yard and all the vertical transition will happen on the leads. The tricky part is crossovers since model railroads generlly have the tracks so close that there is no room to make a vertical transition in the crossover itself, so that has to be at the same elevation as the main.
I have used cork sanded down, balsa wood sanded down and nothing. If you are balasting the track you don't necessarily need anything under it if its a short transition. Once you apply ballast and glue it, it forms its own support (after all, ballast is what the prototype uses).
Dave H.
Dave H. Painted side goes up. My website : wnbranch.com
Thanks to all for coming to the rescue!
I still am a little unclear as to where to put this slope. If one starts from the main and uses a turnout to a turnout to start the yard at the deck level, do you start tapering below that second turnout?
I exaggerated when I said 1/2" as I now measured the HO cork at 0.2" only. What a difference to think about, guess I have less of a problem than I thought!
Grampys Trains - I consider that the better idea but in doing the math, it looks bad?
If I need to drop 0.2" in say a 3" spanning section, to my poor math skills, that would represent about a 6% grade?? I figure - if 1"=96" as a 1% grade in HO, then 0.2" in 3" would be about 6" in 96". Have I got that right?
Anyway, I think I can more gradually taper the yard from its turnout better but I may combine both techniques.
Thankd for all the advice to all.
Hi jake9: I would't worry about the grade %, because it's so short. If you make the top and bottom a smooth transition, you should'nt have any problem. My mains are on 1/4" cork and my yard is on, I think, 1/8" cork. The actual ramp is about 5-6" long. The only problem I can see is possible uncouplling at the top and bottom of the ramp. Try setting up a small trial area with some track simulating your main and yard levels. Then try a loco and some of your cars to see if it will work for you. In this photo, in the lower left, my yard lead connects to the main, using the method I described. I haven't had any problems. I run 4&6 axle deisels. I haven't tried my one steam engine, yet. Good luck!