Normal rail head width is 3 inches. Controlled cooling prevents formation of hydrogen flakes (also called shatter cracks or internal thermal ruptures). Hydrogen can be a source of internal transverse/compound defects leading to broken rails. These internal growths are called transverse or compound fissures.
This is also referred to as a crushed head and/or battered head. Rail end batter is the result of the impact of wheels passing over the joint, it occurs more frequently over joints where bolts have worked loose, and is more prevalent over joints that have mud and are not supported well by having good ballast. We have good ballast there now because we cribbed these ties out, but there was a lot of mud there which helped cause this and make it worse.
Since this video was made, all new rail has been put in on the low side of this curve and this joint has been eliminated.
132 RE stands for the rail section as defined by AREA (American Railway Engineering Association)
Our aluminum cars loaded including car weight, weigh about 286,000 pounds, this means that every wheel that passes over a joint hits that joint with a weight of 35,750 pounds. Imagine that weight hitting that joint 6 to 7 times a day, day after day. It's amazing that more of these battered heads don't happen.