Newbie here. I read where someone designed a layout using code 83 for mainline track, 70 for sidings and 55 for spurs.
What is the rationale for chosing different code track for different purposes.
Here I thought the only track types were code 100 and code 83.
Real rail is different sizes so modelers use different size rail.
In the real world the more heavier traveled rail is thicker to with stand the wear and sidings are smaller to save on cost. In our world the smaller size (code) requires finer detail to avoid derailments. Also smaller rail is more realistic looking…
IN HO scale, code 100 rail is about the same size as 152 lbs. per yard rail on the prototype. Code 83 represents 132 lbs. per yard, and code 70, 115 lbs. per yard. You can find a chart showing this here.
152 lbs. per yard rail was extremely heavy-duty, and was only used on parts of the Pennsylvania Railroad until manufacturing of that size rail was discontinued in the 1940s. 132 lbs. per yard is used for most main lines, which is why HO modelers prefer code 83 for their main lines. Lighter rails down to about 90 lbs. per yard were used for sidings spurs, and yards. Moreover, earlier railroads were built with lighter rail. As mainlines were upgraded to heavier rail, the lighter rail was reused on secondary trackage. (IIRC, the Missouri-Kansas-Texas Railroad got into a bind because its main lines used 90 lbs. per yard rail.)
In N scale, code 55 is heavier than 152 lbs. per yard, but here we have a compromise: the smaller rail sizes are more fragile, present problems with hand-laying, and might cause problems with cars and locomotives that have deep flanges. And smaller rail is more expensive, too.
Model rail is produced in code 40, 55, 70, 83, and 100. (And heavier rail is produced for the larger scales, but I don’t remember the sizes over code 100. And anything lighter than code 40 I haven’t heard about.) Shinohara makes some N scale track with code 60 rail.
Looks. The lighter rail in places where a real railroad would have used lighter rail looks better.
Wander down to your local 1:1 scale railroad. The main track through town, recently re-laid to handle unit coal trains and Amtrak, is probably 132-140 pound/yard rail, continuous welded, possibly on concrete ties. The passing siding, seldom used, is laid with 115 pound/yard rail and is probably at a lower level than the main, since it hasn’t had its ballast renewed lately. Then there’s that track that straggles off through the weeds to a lumber yard that no longer receives railroad deliveries because modern locos don’t dare venture out on the 75 pound/yard rail spiked to rotted-out ties.
Many years ago (New York Central was still running steam[:-^] ) I found one of those wander off into the weeds spurs (yes, it served a lumber yard.) At the switch connecting it to the main track was a sign warning that locomotives of certain classes were not permitted onto the spur. About a hundred yards short of the lumber yard gate was another sign, No Locomotive Beyond This Point. When I pushed the brambles aside I found transition joiners to 60 pound rail.
Back in the HO scale world, Code 100 is oversize for any rail ever laid to support railroad cars. That PRR 155 pound rail would be Code 93 if modeled accurately.
Chuck (Modeling Central Japan in September, 1964)
According to a couple retired workers from the local former B&O yard, because of the heavy loads of ore, Taconite, and coal, pulled often by doubleheaded S-1 2-10-2s and EM-1s, all the track in the local yard, including a couple GP spurs, was laid in the same size track as normal high speed mainline rail, 120-132lb? And so was most of the rail in the local steel plant. Supposedly, this was done for longer life and minimized maintenance. Both these yards were switched by 0-8-0s well into the diesel era.
And yes, not only the S-1s were often doubleheaded, I’ve seen doubleheaded EM-1s used because of something like a 1/2-3/4% outbound grade, and over 100 70 ton hoppers in a train. Sometimes to get started, especially in the winter or rain, even one or two L-2 0-8-0s had to be coupled in front and back.
Maybe one doesn’t really need to go to a smaller rail section for larger HD yards?