I have a small mountain yard that I've devised, with several quirky features...and wanted to ask you whether these were plausible or not...
My yard is in a small "bowl" as compared to the mainline which passes by on the curve. It dips down from the mainline, having lead ramps of 2-4%, depending upon the ramp location. Is this something that a real railroad might have? I raised the mainline 1/4 inch above the yard lead (HO, BTW), and another 1/4 inch above my industrial/switching area both for scenic interest as well as because I'm aware that sidings and yards are usually a below the height of the mainline. Just wondering whether I'm overdoing it because of the short ramps in my confined space. It's a sharp ramp.
Do railroads occasionally have stiff grades for very short stretches such as ramps? Is it more common for a yard to be on an even grade with the mainline?
Would it be unusual for a yard to have a slight "bowl"-like look to it?
Lastly, I have a question about mainline grades. I have a short stretch of mainline where the grade rise is 2% - mostly done for scenic interest (ironically, it's near the yard). I know that railroads generally follow the lay of the flatest land...but if there were a half mile or so of 2% grade that was "unavoidable", would they follow it or burrow and flatten it? I'm trying to feel comfortable with my justification of the 2% grade. I'm modeling an old southeastern coal branch line, spun off in contemporary times to a shortline.
I've always pondered the "ruling grade" issue, wondering whether and in which cases railroads work at any cost to have a relatively flat grade, or when they would just follow the lay of the land, albeit a brief 1% grade and not make a cut. When looking at real road grades, it's hard for me to see the grade other than the sharper examples. If there was an anavoidable hill for a stretch - not a mountain but a hill - do they just wipe it out or make a long cut?
Thanks for answering my somewhat obscure questions.
David B. - Thanks! I was worried about the yard dip, but it really will add something to the scenic drama, along with the short 2% mainline grade, I think. It's funny, but when I look at a 2% grade in HO it seems barely perceptable to me (though I know in the prototype that would be considered a significant grade), but when I look at a 3% grade, it looks steep and noticeable...but not abnormal. A 4% grade looks like a real ramp up, and out of place. There's a real differential in look that is just not incremental. The rule of thumb I've thought about is that a 2% HO grade looks to my eyes more like a 1% prototype grade. Outside of my long mountain pass run, I ripped out all my 3% grades and made them 2% or less.
I'll definitely post something when I'm finally through with the base construction phase, putting things in, ripping things out. I'm still covered with foam. I'm guessing I still have several months to go before I can post something that wouldn't be embarassing.
73
Bruce in the Peg
Bruce, my ramps are all straight sections, thank goodness. I did try to steer away from a curved ramp. However, interestingly, my yard is partially on a curve. Separate 26" and a 24" sections on different yard tracks. My uncoupling action will occur on straight sections, however,and one small piece of 34" track, which tested out fine.
My "Bells Valley Yard"...the engineers are going to nickname it "the bowl".