I just picked up the latest trains magazine and a great article on CWR.
Field weld was briefly mentioned in the the article. On the CN line north of Toronto I notice that short rail was field welded to what appeared to be continuous rail. Why is this now not a more common practice before it would require a CWR
Many thanks to all who replied to my question a while back re scrap rail.
Thermite(r) field welding is a slow and expensive process compared to bolted joints. The joint also requires a lot of grinding to restore the rail profile after welding. Continuous welded rail really became practical with the development of butt welding equipment - which due to power and joining surface requirements - is an in-shop operation.
dd
Whilst waiting at a crossing for an excursion to pass I was checking out the rest of the geography near the crossing and noticed that the CWR was made up of numerous sticks of standard 39’ rail welded together. The uniformity of the weldss makes me believe it was probably as dd says - an in-shop job. The dates on the rail ran in the 1940’s, and the bolt holes were still there, which is what tipped me off to study the rail more closely.
That said, it would appear that the CWR I saw was recycled rail, picked up from somewhere, taken to a welding facility, then installed where needed.
One thermite weld costs $880 for just the materials…Add labor for a two man gang at about 3 hours, track time, special welders truck rental and well, the story is obvious.
A flash but weld is somewhat cheaper, but requires more manpower and great bunches of preparation and planning. Rio Grande preferred to flash-butt weld almost everything. After a few D-Car runs and other forms of rail change-out, they had an odd looking jointed railroad for months (or years depending on the budget) until Holland showed up to do its thing. Plus sliding all the rail to eliminate end battered rail, cropped sections, wheel burns, etc…
Mark did not mention the molded cold-weld/ gas weld process that SP adopted (not thermite, not gas weld) that they eventually abandoned because of the high defect rate.
Denver RTD light rail & Holland are welding together strings of rail right now on the shoulder of I-25 /T-Rex using a mobile plant, jigs and a herd of speed swings all night long.
And should moisture ever get into the thermite charge…RUN![B)]
[banghead][banghead][banghead]
Thanks for the update on in-field flash butt welding. We use a very similar technique for field welding stainless steel piping - but there is a big difference between 12mm diameter stainless piping and 132 pound rail!
dd
thanks to all for the info to my question.
I’m out of the area right now but when I get back to where I noticed the rail, I’ll be checking it more closely, checking for the weight of the rail etc.
One thing I did notice was the ties were quite old and a lot of the spikes had popped up quite a bit. I would imagine that what I noticed back then was of a relatively short distance otherwise there would be buckling of the rail due to expansion ???
While CWR has seriously reduced the level of maintenance that is routinely required to keep acceptable track standards, there is one drawback that has yet to be totally solved.
Weather. The cyclical heating and cooling of the rail that causes expansion and contraction within the metalurgy of the rail. The longer the string of rail the more stress that are built up when the weather goes outside the bounds of the normalized temperature that the rail was laid at.
While there are numerous rail anchoring products and technologies applied to CWR by the various railroads. The extremes of Summer Heat and Winter Cold will always find the weakest spot in the rail and a broken rail is one result in the Winter, buckled track finds the weakest ballast shoulder in the Summer. Unfortunately, while constant inspection may find many of the occurences, more occurences are found by trains…the hard way. Of the two occuences, buckled track is the most threatending as witness the Cresent City, FL Autotrain derailment. However, broken rails are the more insideous occurence. Insideous because they are routinely taken for granted. Train operates through a track segment and leaves a track circujit light up on the Dispatchers model board. Signal department personnel are notified and investigate, finding the broken rail. The reality of the situation is…THERE BUT FOR THE GRACE OF GOD, WAS A CATASTROPHIC DERAILMENT; as the rail broke while the train was traversing over it.
CWR a technology that has yet to be MASTERED.