Sunday, November 28, 2021

Rail Length


Getting ready to move a pile of rail from here to there at Depot St. I walked about 3 miles around the circumference of a 20’ radius circle in an afternoon.

What I also found interesting is the ratio we were moving. It was rolled in 1915 and 1922 for the NH, 107 lb rail taken out of the Canal Line near the Massachusetts border.

New Haven Rail

What’s the length of a piece of rail? The conventional knowledge is 39-feet, so it would fit in 40-foot gondolas. While that is true, 40-foot gondolas weren’t always the standard length pre-depression. In addition the surveying, real estate, and railroad industries use some standard systems of measurement.

These rails are two rods long, or 33-feet long, a rod being 16.5-feet. Of course, that worked well since it fit in 36-foot cars. The NH didn’t have 40’ gondolas (or flat cars) until the 58000-series of gondolas were built in 1929. (For more on those, including a diagram, see this post.) So they may have continued to receive 33-foot rail until those cars were built.

The 16.5-foot rod is related to other measurements - a chain is 4 rods (66-feet), a furlong is 10 chains (660 feet), and a statute mile is 80 chains. The surveyors’ chain is just that. A chain with 66 foot long links.

So for those modeling earlier eras (pre-depression to a large degree), it may be more appropriate to put those joint bars every 33 feet instead of 39 feet. This is appropriate on some lines even today, large portions of the CNZR is CNE/NH rail from pre-1926, the oldest I think from 1896-7. The Highland Line is still largely 107 lb NH rail, so I’ll have to go take a closer look at when it was produced. I suspect that I’ll need to go with that measurement on the layout.

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