Rail Code, HO

The rail code is the height in thou, so to get the equivalent prototype height in inches multiply by the scale factor (87) and divide by 1000. So code 100 is 100*87/1000 = 8.7 inches. code 83 is 83*87/1000 = 7.2 inches code 75 is 75*87/1000 = 6.5 inches code 70 is 70*87/1000 = 6.1 inches code 55 is 55*87/1000 = 4.8 inches

Keith Make friends in the hobby. Visit Garratt photos for the big steam lovers.

And note that rail on heavily travelled lines these days is about 7 inches tall, so code 83 represents it fairly well.

Code 100 represents 8.3 inches, which is about as heavy a rail as was ever used (on the PRR, IIRC.)

The cross section of the rail is designed to a) not flex too much when a heavy load (axle) passes over it -- excessive flex means excessive wear on ties, loosening of spikes, "pumping" of ballast, and such; and b) wear slowly, so it doesn't have to be replaced to often; and c) cost as little as possible while meeting a) and b). Aside from the steel itself, the height of the rail affects a), and the depth of the railhead affects b).

HTH

ty both

-- DW

Hey Wolf, you lost 0.4 of an inch! or are you implying that my maths is wrong? -:) Keith

Make friends in the hobby. Visit Garratt photos for the big steam lovers.

I once measured rail that was 8 inches tall on the SP between San Jose and San Francisco. That was where the heavy commuter traffic was. I guess maybe Cal-Trans has taken that over??????

Did you happen to note the weight rail that was? The largest I've been around is 140#.

-- DW

HTH... and your figures are quite accurate I might add :-)

code 100 is 100*87/1000 = 8.7 inches 140 PS is 7.3", I don't know this one.. anyone? code 83 is 83*87/1000 = 7.2 inches 132 RE Very common main rail here in N.E. US code 75 is 75*87/1000 = 6.5 inches 110 - 115 RE Very common secondary rail here in N.E. US code 70 is 70*87/1000 = 6.1 inches 100 RA - 105 Dudley Very common branch rail here in N.E. US code 55 is 55*87/1000 = 4.8 inches 70 ASCE - 80 RB I was around this once when an abandoned line was restored, but the rail had to be replaced in just months of medium modern traffic. LOL

-- DW

Prototype rail is usually measured in lbs per yard (or kgs per metre) rather than height.

There are probably slight differences between diffent manufacturers as well.

From an old Model Railroader Rail weight height in lbs inches

12 2.00 20 2.63 25 2.75 35 3.31 40 3.50 56 4.00 60 4.19 75 4.81 80 5.00 100 6.00 120 6.50 131 7.13 152 8.00

So, in HO, Code 100 is equivalent to 8.70", Code 83 is 7.22" (131#) and Code 70 is 6.09" (100#)

Nope, just that "about 7 inches tall" is close enough to actual dimensions, which vary a bit. Height is not the only factor determining rail's weight per yard - profiles of the same weight vary in web thickness, base width, height, etc. IOW, code 83 represents 100lb rail well enough that only the nittiest of pickers would object. I'm not a nit picker. Well, not about rail, anyhow. :-)

HTH&HF

Wolf Kirchmeir wrote: [...]

Oops, that should be 132 lb rail, my error.