03-19-2017, 12:00 AM
(This post was last modified: 03-19-2017, 12:04 AM by danbrotherston.)
(03-18-2017, 07:52 PM)ijmorlan Wrote:(03-18-2017, 12:56 PM)Square Wrote: ^^ What about the Northfield Bridge? Was a gap in the rail where it changed from embedded to ballasted track, now I saw that it got welded.
Question about welding where there was a gap: for welding, wouldn’t the two pieces of rail need to touch each other? So how does the gap get filled? Does the welding actually fill the gap, or do they pull the rails together, or something else entirely?
I'm under the impression, from my admittedly amateur understanding of how welding works, and from videos I've seen, that the weld will bridge some gap, possibly a gap is even necessary. The process of welding actually adds material. In more traditional welding there is a steel rod as the added material, but in thermite welding, I believe the added iron material is a product of the thermite reaction which also produces the heat.
https://www.youtube.com/watch?v=KNBDWuWz9ZE
https://en.wikipedia.org/wiki/Exothermic_welding