Guard rail (rail)

In rail transport, guard rails or check rails are rails used in the construction of the track. placed parallel to regular running rail, and keep the wheels of rolling stock in alignment in case of derailment. They are generally used along areas of restricted clearance, such as a bridge, trestle, tunnel, or level crossing. They also helps to minimize damage to the structure and allows easier post-accident cleanup.

This article is about railway infrastructure. For highway infrastructure, see Guard rail.
Guard rails at Diêu Trì railway station, Vietnam
Track with guard rails in Myanmar, near Pekon

History

Although guard rails in some form have been used as long as there have been trains, the precursor of the guard rails we have today was detailed in U.S. Patent 522,038, filed in 1893 by Gorham B. Ames, based in Laconia, New Hampshire, USA.[1]

Sharp curves

On sharp curves, guard rails may be placed inside the inner rail, where they engage the back of the flange of the wheel on that side.[2]

gollark: ```pythonimport collectionsdef do_thing(s): if len(s) == 1: return { s[0]: True } out = {} for i, c in enumerate(s): without = s[:i] + s[i + 1:] things = do_thing(without) out[c] = things return outdef match(r, s): print(r) c = r for i, x in enumerate(s): print(x) try: c = c[x] if c == True: if i + 1 == len(s): return True # full match else: return False # characters remain except KeyError: return False # no match return False # incomplete matchentry = lambda a, b: match(do_thing(a.lower().replace(" ", "")), b.lower().replace(" ", ""))```Here is my entry (pending a port to osmarkslisp™️). This is definitely my entry.
gollark: I wish to use Mathematica in my code. Please install it. DO NOT READ, ubq.
gollark: I have a "great" way to do this which I think takes O(n²) space-time-beeite.
gollark: Perhaps it is also possible to construct some sort of regex/deterministic finite automaton to match things matching anagramatically.
gollark: Bogothings run in O(n!) time mostly. So just make `giveup`'s maximum be `math.factorial(len(remove_whitespace(s)))`.

References
  1. US 522038, Ames, Gorham B., "Guard-rail", issued June 26, 1894
  2. "Mildura Train Derailment". The Argus. Melbourne. 27 August 1928. p. 16. Retrieved 5 August 2011 – via National Library of Australia.


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