Real-world continuous rail question

[MisterBeasley]

A co-worker at lunch today mentioned that he saw an unusual sight in Shirley, Massachusetts yesterday. There was a maintenance train dropping off a very long piece of rail. It was carried on multiple flatcars, and was being slid off the rear of the train in one long, continuous process. His estimate was that the piece of rail was a thousand feet long.

That seems a bit high to me, but even if the rail section were a few hundred feet, it poses a problem. How do they put this in and still allow for expansion and contraction? In this part of the country, the temperature can be 15 below zero Fahrenheit, or as high as the 90's in the summer. I guess the same situation would apply to welded rail used for high-speed applications.

And we worry about a 3-foot section of flex-track!

[Big_Boy_4005]

I believe those are quarter mile sections, and the railroads have been using them for years. Yes they expand and contract, but the track is not "NAILED" down, and can move and shift slightly. Tolerences on a real railroad aren't as small as on model railroads. A quarter inch for them is nothing, a quarter inch for us is the "Grand Canyon".

One factor that you may be overlooking here is that while the range of temperatures may be wide, the short term fluctuation is not that great. Drastic and sudden changes can cause problems. "Sun kinks" are not that uncommon.

[Anonymous]

In addition, the J-shaped clips that are attached to the bottom of the rail force the rail to expand and contract vertically, minimising (usually) the horizontal pitfalls of expansion.

[nfmisso]

1320 feet

[cwclark]

i'd like to also mention that the long rail is long for a purpose...long rail means fewer welds to join them together and the longer the rail the faster the trains can go and the smoother the ride....Chuck

[BR60103]

There's another thread on this in the Trains section.
Continuous rail is actually laid at a warm temperature (they heat it in winter) and is usually in tension. Whatever, if something distubs it like a derailment, it does move around a bit.