During a recent trip North aboard the Amtrack Starlight we were detained for several hours by a split rail. I would like to know exactly what this is, how often do they occur and how they are repaired.
The damaged rail most likely will be scrapped and replaced with a new one.
Several different kinds of split rails.
One that has the worst safety implication is a “vertical split rail” - the split is vertical, essentially right down the middle. Often it originates in the comparatively thinner web area - looks kind of like this: (( )) or if you place the palms of your hands together facing each other (as in the praying position) and then cup them slightly - and then propagates up into the head and sometimes down into the base as well. My understanding is that this often results from imperfect “knitting” or binding togther of different layers of steel in the rolling mill. Usually not visible until the split reaches the top of the rail, when it usually becomes visible as a streak of rust. If you want to know more, find and look at the AREMA Manual, which has extensive illustrations, or try to search for “vertical split head” or “VSH” - I saw about 1,070 “hits” for that. Not very common anymore, with improved rail metallurgy and quality control at the mills - may be found in older rails still in track, depending on which line you were on.
Another and more common one is “horizontal split head”, or “HSH”. It too can be caused by sn internal rail defect, but more often these days is caused by a lot of heavy traffic. Repetitive loads of that type over time overstresses the metal in the middle of the rail head and causes it to shear apart in a horizontal plane, which then propagates out to either side of the head, and leads to the top of the rail head peeling up in a layer from 1/2 to 1" thick, which greatly weakens the rail at that point and creates an impaact loading point. Again, the AREMA Manual or a search will tell you more.
Hope this is helpful.
- Paul North.
Split rail or split switch? (human error)…wondering if the original poster (Swabbie) got some second or third hand info where the defect term had evolved into “split rail” which isn’t a normal railroad term which had me wondering head-web separaration or piped rail near the top ball of rail (mill defect, rare anymore in this day and age)
This had worked so far into the mud that I couldn’t find any mill stamp information on it – Ex-Milwaukee line into shop area and roundhouse.
