Trying to lay out a Yard

If you have a great deal of space, or long rolling stock, use the number 6 switch. If you don't then use a 4.

I should of been more specific. What curve piece do you use?

ChrisGW

Your question is too vague. I would use flex track and make it the largest radius that will fit the space given. Is the yard on a curve?

Take a look at the NMRA standards for turnouts at

You need to deal with two issues - what radius curve to use and how many degrees of arc of the curve are needed.

If you're using #4 turnouts, NMRA dimension #11 says the radius of the curved diverging rails is 15", so you might think that using 15" radius curves with these turnouts in a ladder would be no worse. But since the length of the curved rails in the turnout is short, and is ameliorated by the broad 43" radius (NMRA dimension #6) of the points and the straight rail through the frog, the effective radius of the turnout is more broad, so I'd suggest using 18" radius Atlas track. NMRA dimension #18 says the angle of the #4 turnout is 14.25 degrees. Thus you need this much arc in the diverging route to get the track back to parallel with the tangent route through the turnout. This is about 15 degrees, which would be a 1/2 section of 18" radius track (with 12 sections to a 360 degree circle, so each standard 18" curve has an arc of 30 degrees). (But note this is all a little off, as Atlas #4 turnouts are actually about #4.5).

If you're using #6 turnouts, the NMRA dimensions say the tightest radius in the turnout is 43", and the effective radius with the straight frog is even more broad, so using Atlas 22" radius Snap Track is undoing any advantage from the broad turnouts. As another poster commented, you'd be best off using flex track. If you do choose to use 22" radius Snap Track, NMRA dimension #18 says you need about 9.5 degrees of arc. Atlas 22" radius track uses 16 sections to a circle, so each section is 22.5 degrees of arc. This then says you need to use a special cut section a bit less than half a regular section of 22" radius track.

Since almost no one wants the limitations of a 15" minimum radius curve layout from #4 turnouts, and since 43" radius is so generous and yard ladders made of #6 turnouts use so much real estate (yard length, or shortened yard tracks), I suggest you look at using Walthers/Shinohara #5 turnouts in your yard as an excellent compromise for smooth operation in a reasonable space. Geezer

ChrisGW wrote:

The problem/challange in model rail road yards is to get enough yard track into the never-big-enough space available. You want long sidings, and many of them to allow you to break up a long freight train and sort the cars out be destination. For instance your "Hotshot Transcontinental" with 50 cars pulls into the yard. You want to break it up and set the cars going to Manchester on one track, the cars going to Concord on another track, the cars for Bellows Falls and Mechanicsburg and Ipswitch all deserve their own sidings, so they can go out as peddler freights later on. We are splitting up 100 cars five ways, so each siding wants to hold at least 10 cars. Plus, rolling stock expands to fill available track, so anyway you play it, you want as much yard track as you can squeeze in. The sharper a turnout you can use, the more trackage you can squeeze in. Freight cars are (mostly) shorter than passenger cars and will take a #4 turnout, no problem. If you are using Snap-Track, the traditional Snaptrack turnouts are equivanent to an 18" carve track section married into a straight section. These are slightly different from true #4 and #6 turnouts where the diverging track is STRAIGHT. Your layout design program ought to understand the difference between the two turnout styles. Was it me, I'd go with the sharpest possible turnout to save space. I'd think about modeling the transition era (1950's) so I can keep my freight cars down to 40 footers, and use a small switch engine, maybe even an 0-4-0 steamer to handle the sharp curves. I'd allow for uncoupling magnets on each siding. I'd allow finger clearance between sidings to handle derailments. I'd want LED's to indicate turnout positions to prevent confused engineers from running thru turnouts set against them. I'd avoid any S bends. I'd want the yard lead to be straight, no curves 'cause the yard moves are backing moves that are more likely to derail than forward moves. I'd want toggle switches to turn off the track power on each yard siding so I could leave locomotives on them. I'd want to be able to reach the last and farthest sideing in case of derailments.

David Starr

Try not using a curved section. If you can squeeze in a parallelogram shaped yard then you can run onto the diverging track and run straight to the exit turnout.

As others have posted, available space will probably drive your design more than anything else.

Good luck, Paul

I am going to use the flex track. I played around with it last night and that seems to be the way to go. The entrance to the yard will be off a curve. I am going to Fredericksburg, va for a few days, so I will work on it when I get back. Will also be visiting "Granddads Hobby" shop in springfield and pick up more switches and flex track. I am adding three more turnouts.

ChrisGW

Great info. Thank you very much.

ChrisGW