Back in the 40’s when they were still laying rail by hand
what was the common length of a section of rail ?
TIA
39 ft.
Dave H.
Agreed. 39 feet.
All the track near me looks like it’s still 39’ rail.
Hummmmmmmmm thanks guys !!!
Kinda begs the question why 39 feet ?
why not an even number like 40
the rails were that length so they would fit on a 40’ flat or in a 40’ gondola.
Or are 40 ft flat cars 40 ft so they can carry a rail?
Were the rails sized to fit the cars or the cars sized to fit the rails?
I would think that the the length of the rail has more to do with the rail making process or the fact that its a multiple of an odd number than that it was convienent to fit on a car.
Dave H.
Hi dehusman
40’ cars are 40’ because thats what the traffic branch asked for so thats what the engineer designed.
That is also what was technicaly possable at the time they where introduced.
To some degree the size of the transporter does influence the size of a given product.
But not always.
A case in point is a modern section of one mile flash butt welded rail it will not fit on one car but it does fit on the steel train taking it to the work site.
regards John Busby
Standard inside length of most ‘transition era’ freight equipment is 40’. This is the number the customer is interested in. Rail has been rolled in lengths from 30’ to 80’ at times. I have seen 60’ rail that was rolled for special applications(grade crossings) where a buried joint would be a problem to service. 39’ has been a standard for jointed or ‘stick’ rail for many years. Thermite welding has sort of eliminated the need for ‘special’ lengths, and 1/4 mile ribbons of CWS seem to be the standard for any new construction or upgrading of existing track structure.
So, to answer the question about if this is a ‘rolling mill’ limitation, 39’ is not the upper limit for rolling mills that produce rail.
Jim
I had never really given it a lot of thought but that would mean that each section of N rail would need to be 2.925 inches… thats a lot of rail sections!!
Chris
And noisy too !!!
I read somewhere that that 39 ft rail length was one of the contributing factors in the demise of Penn Central. According to the author when rail cars were 40 foot in length the truck centers were about 30 feet but when car length increased to 50 feet the truck centers increased to about 40 feet. This caused the trucks on a rolling freight car to collide with the gaps between rails at the same time and it set up a shock in the rail. Deferring maintenance added to the problem and as the trackwork got worse speeds were lowered and the whole system began to disintegrate.
So said this author.
Sorta. Its around 40 ft for boxcars, but not for hoppers aand there were a gons and flat cars that were odd sizes. A typical steel flat car is 53’6" and gons were 41ft to 52’6". When 39 ft rails started to be made the average car size was more in the 34-36 ft. range.
Not now, but how about rolling mills back in the 1880’s or 1890’s?
Dave H.
So, which came first??? The 40’ flat car [Hen] or the 39’ rail [Egg] ???
39’ was used in order to avoid setting up a resonance effect within the track, from multiple wheels hitting the joints at the same time. Otherwise, certain train speeds might result in wheels hiting the rail joints at the natural frequency (or some harmonic of it) of the track, which would induce energy build-up that could cause damage to the track structure through vibration, loosening the spikes and displacing ballast. Ties could even move sideways if a strong enough resonance occurred.
Like rtpoteet said, though I don’t know about the Penn Central aspect of the story.
Another point is that normal US practice was to stagger the rail joints - the rail ends on one side of the track approximately centered on the rails on the other side. When the resonance length of the cars wasn’t 39 feet this was no big thing. When the resonance length got close to 39 feet the result was a rolling motion that could quickly amplify to dangerous magnitudes - especially since freight car trucks didn’t have any kind of roll dampers or shock absorbers.
The normal practice in England, Japan and many other countries was to have rail joints directly across from one another. Presumably fore and aft pitching was preferable to side-to-side rolling.
Another practice to note was that end-battered rail pulled up by the maintenance crews would frequently have the damaged ends cut off. The remaining length would then be used to upgrade a light-rail branch or industrial spur. While waiting for re-lay, those odd lengths would usually have one or both ends painted to let the MW folks know that the rail was shorter than the standard 39 feet.
All of which is academic to me. My prototype was laid with 16 and 20 meter rails.
Chuck (modeling Central Japan in September, 1964)
So what dit they do on curves, trim each rail? On a 1000 ft radius, a 90 degree curve would end up with the rail joints offset by 4 ft by the end of the curve.
Dave H.
They did the same thing that American railroads did - a certain degree of misalignment could be tolerated, then ONE rail would be shortened enough to reverse the mismatch.
Another difference was that the ties supporting a rail joint were much more closely spaced than those supporting the main part of the rail. A centimeter or so of mismatch could be accepted. After that, out came the rail saw…
Chuck (modeling Central Japan in September, 1964 - with simulated rail joints on 20m centers)
I was really hoping the answer would be 30 feet
because i bought 12, 30ft flat cars and was going to load them with rail sections
[%-)]
Old time rail lengths may have been different, shorter cars even. Go for it.
I would tend to think any given rail length was made for the convenience of how to transport it to the laying site.
Welding track onsite came along, then somewhere an idea came to weld track before laying it, so specialized welded rail flat cars were designed.