After reading a bit more about the derailment of the Capitol Limited, it appeared that the track had no expansion joints. Either this is the usual media bad reporting, or is this really true? Even pre-stressing the track at installation isn't going to help beyond a certain temperature.
Expansion joints are used in welded track to allow for expansion of the rails. They are not like bolted track joints, where the cut is at right angles to the rail, but more S-shaped. This gives a much smoother ride over, even if the rail has shrunk.
So, are there no expansion joints, or is it bad media reporting?
Geoff M.
Posted by MPALMER (Member # 125) on :
Geoff,
I had not seen expansion joints before...thanks for the photo/clarification. But I don't have an answer to your question re: the accuracy of the reporting.
M P
Posted by vthokie (Member # 1456) on :
I've been around railroad tracks quite a bit, including the high speed Northeast Corridor and other heavily used routes, and I don't recall ever seeing one of those!
Posted by jimmymac (Member # 1182) on :
I took the Sunset Limited from Florida to California. I remember seeign welded rails at the stop in Palm Springs but no expansion joints. I was pointing out the welds in rails to my teenage daughter and I remembered that older rails that I used to see in Philadelphia in my younger days had bolted connections with a space between the joints.
Posted by Kairho (Member # 1567) on :
I believe I read somewhere that the expansion joints on welded rail were 2500 feet apart. If true, chances of a joint near a station are low.
Posted by vthokie (Member # 1456) on :
Well, as a kid I did my share of walking along railroad tracks, covering many miles, and I never saw those. I would see conventional rail joints every so often on welded rail tracks, and maybe that serves the same purpose, but not anything like what's shown in that photo.
Posted by rresor (Member # 128) on :
No expansion joints in welded rail, except maybe at bridges or some other special location. The rail is anchored at each tie, and actually expands and contracts by changing its cross section (since it can't expand longitudinally).
Two things are needed to minimize the chance of sun kinks:
1) A good ballast section (AREMA standard is 18" of ballast beyond the ends of the ties, measured from the midpoint of the height of each tie
2) Laying at a proper "neutral temperature". Railroads use rail heaters so the rail is laid at a high temperature (how high depends upon local climate). This puts the rail in tension most of the time.
Also, it's important not to disturb the ballast (e.g. by tamping) when CWR is hot. Conrail used to annul surfacing work for "high temperature CWR". CSXT apparently does not.
Bottom line: sun kinks result from improper maintenance practices.
Posted by atsf3751 (Member # 1538) on :
Might many sun-kinks be prevented in CWR if railroads put in a standard joint every few thousand feet rather than welding the whole thing together?
Posted by Kairho (Member # 1567) on :
From the Orlando Sentinel:
""Good track does not buckle!" wrote Andrew Kish, an authority on continuous welded rail who does research for the U.S. Department of Transportation, in 1995. "Sound maintenance, installation and inspection practices will prevent catastrophic derailments."
"Maintenance, though, has been a CSX sore spot for several years. Since the late 1990s, federal investigators have criticized CSX for shoddy work and poor-quality track."