#4, #6, #8 turnouts
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That is twice in 24 hours that I have seen this guy quoted. Who is he?
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Correct, the numbers are the ratio that diverging route comes off the switch compared to length of the straight section. For example, a no. 6 turnout spreads one unit for each six units of travel measured from the frog (the point at which two rails join to form a V). A #4 switch will have the sharpest radius on the diverging route, equivalent to between a 15" to 18" curve, depending on the brand of the switch. A #8 switch has about a 28" to 30" curve on the diverging route, again with some variation between switch brands. The larger the number switch, the bigger the equipment you can run on the diverging route, the smoother things will operate, and the cars will look more realistic because they will have less overhang. I'm sure all of us would use #8 switches if we could but the downside to bigger switches is they take up a lot more space. #4 switches are the most common on smaller layouts with the larger switches being used wherever there's space or more generally on larger layouts.
IronBeltKen
Lazy Daydreamer
I use #10's on main line crossovers, since I run a lot of 89ft auto racks and want to avoid an 'S' curve effect. For yard throats/ladders, I use #8's and #6's (depending on the length of cars I plan to have in a particular yard). I only use #4's on short industrial spurs.
John Armstrong advised against using anything smaller than a #5 on a yard throat, to prevent 'S curve' derailments.
John Armstrong advised against using anything smaller than a #5 on a yard throat, to prevent 'S curve' derailments.
macjet
Member
That is twice in 24 hours that I have seen this guy quoted. Who is he?
There's a good article about John Armstrong at http://en.wikipedia.org/wiki/John_Armstrong_(model_railroader). He was a mechanical engineer and was the first person to bring about the idea the so common today - your railroad should exist for a purpose and everything on the layout should help fulfill that purpose. His great legacy is track planning with that idea in mind. His own model railroading skills were really not that good, except for hand laying track. He claims to have handlaid over five actual miles of O scale track before his death in 2004. His layout always had a rather tinplate look about it and he never got the scenery done that he urged everyone else to do. Nevertheless, his layout and operations books remain the bibles of model railroading today. Check out the related story of John Allen for a guy who actually did most of what John Armstrong wrote about.
IronBeltKen
Lazy Daydreamer
Here's a link to his best-known book, Track Planning For Realistic Operation. A must-read for anybody who's hoping to build a successful layout. (Sure wish I'd read it before I built my current pike...
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I think a #20 would take up just about half my front mainline.The higher the number, the bigger the switch. On past layouts I had hand-laid #12's for sidings on my mainline. They looked good, but were over 22 inches long! #10 looks great for industrial and yard sidings, #8's also look great. I wouldn't want to go below a #8, else the turnout looks too sharp, and locomotives and cars look rather odd going over them.
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