In another thread the guys were talking about turnouts for switch backs,and the need for level track on both ends of the turn out.
My question is how mutch level track? Is it dependent on the equipement used, or is there a rule of thumb?
UNCLEBUTCHMy question is how mutch level track? Is it dependent on the equipement used, or is there a rule of thumb?
I allow a distance equal to the longest car length on either side of any turnout before changing grade (not just in switchbacks). Turnouts can be on a grade, I just don't change the grade within or near the turnout. Other designers may be less conservative.
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That would make the most sense. I'm not sure why you couldn't have a turnout on a grade, as long as you do not CHANGE grade. Side to side could be problematic, helping wheels pick the points or the frog to the downhill side. But along the length of the track, so long as it was all even on both sides and through the turnout, should be no less reliable than a level turnout.
--Randy
Modeling the Reading Railroad in the 1950's
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cuyamaI allow a distance equal to the longest car length on either side of any turnout before changing grade
I don't have any experience that would contradict this advice, but I'm curious why you wouldn't start the vertical curve as soon as you're off the turnout.
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carl425I don't have any experience that would contradict this advice, but I'm curious why you wouldn't start the vertical curve as soon as you're off the turnout.
You can but,it would have to be gradual like a industrial siding that is lower then the main.
A sudden raise or drop in the track can cause issues like a pilot or snow plow striking the rail to cars uncoupling if the couplers are not perfectly in gauge.
Larry
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Summerset Ry.
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BRAKIEYou can but,it would have to be gradual like a industrial siding that is lower then the main
Yes, I get that. It always has to be gradual - that's track laying 101, but why the 1-car length of level track between the turnout and the start of the grade?
It's easy for the grade to slide into subroadbed under the turnout during construction unless great care is taken. In addition, there's always a track joint at that point -- and a grade transition exactly at a track joint is usually trouble.
As I said, it’s possibly a bit conservative. I design for others to build, so I want to maximize reliability. On the flip side, I can’t count how many times I’ve seen reliability problems result from a grade starting right at or within the turnout – and it’s an error found in many published plans.
cuyama carl425 I don't have any experience that would contradict this advice, but I'm curious why you wouldn't start the vertical curve as soon as you're off the turnout. It's easy for the grade to slide into subroadbed under the turnout during construction unless great care is taken. In addition, there's always a track joint at that point -- and a grade transition exactly at a track joint is usually trouble. As I said, it’s possibly a bit conservative. I design for others to build, so I want to maximize reliability. On the flip side, I can’t count how many times I’ve seen reliability problems result from a grade starting right at or within the turnout – and it’s an error found in many published plans.
carl425 I don't have any experience that would contradict this advice, but I'm curious why you wouldn't start the vertical curve as soon as you're off the turnout.
Yes, precisely, Byron. Those of us very patient and highly skilled at laying bullet-proof track could get away with a change of grade near a frog and its guards, but like any change of grade on rails, scale or not, it must be a vertical curve starting with the grade of the frog rails. For the rest of us mere mortals, giving our rolling stock and long-wheelbased engines about a boxcar length from the frog before starting the grade is cheap insurance and will keep us from developing anxiety every time we go over that place with a train.