I do not think anything even close to a conventional arc welding process would apply. Even some unconventional processes (hot wire, submerged arc) would not apply. Not to mention the size of the welder that would have to be present, and the skill of the weldor (not a typo- the 'welder' is the machine, the 'weldor' in the guy with blacklung holding the stinger.... and Easy Boys! Not that kind of a stinger) and the time waiting for the rails to cool enough to hit them with another bead. Honestly, I do not know of a welding process that would allow both the vertical as well as the horizontal portions of a railroad rail to be welded. It could be and may be done but not anywhere near as cheaply, as fast, as fast (yep, said it twice) and not anything any idiot could do. And one of the beautiful parts of it is that both pieces of the parent metal (the rails) as well as the filler are all extremely hot and cool slowly; this prevents thermal shock, 'hot shortness' and a whole host of other problems. Plus because it is all done outside the envelope of the atmosphere, all those considerations are gone too, such as hydrogen embrittlement (that one is a real, cast iron BI!CH too), underbead microcracking, oxidation inclusions and so forth. Really, an ingenious but also excellent process.
If I had to choose an alternate method it would be resistance butt welding. It would take a HUGE weldor but hey, that IS the rail company so.... possible. The biggest downside that I can see is that one track would have to be left loose to be driven into the other rail. Again, not a deal- killer but not as easy as what you saw there either.
In the olden' days, they just terminated them on a tie and left it at that- which is what gave trains their typical, familiar 'click- clack' noise. Higher speed trains have necessitated better rails, better ties, and better roads (the bed the ties or sleepers ride on). And just about everyplace outside the US has a need for these better tracks; our own train system, with few, small and isolated exceptions, is really 1950's technology.
By the way, notice how those 'wooden' railroad ties are concrete? And the 'spikes' holding the rails to the ties are bolts? Trains are like that all over Europe and they are very precise, strong and durable. Riding the ICE in Germany is a fantastic experience in no small way because of the rails and materials under the train.... and of course the trains are pretty cool also. There is an annunciator in each car that shows the speed of the train; starting out in Frankfurt am Main, the tracks (gleis) are right next to and parallel with the Autoban. It starts out looking like the cars are gonna' win but the acceleration is pretty strong and very constant and once the train reaches about 140 MPH, most of the cars are going the wrong way (train passing them). Closing in on 200 MPH, and all the cars I saw were coming at me taillights- first. :-) For anyone in Germany for any reason, if you can find the time, try on an ICE (Inner City Express, these are main lines running between large cities, not the regular Deutch Bahn). The trains in The Netherlands are at least as nice, not as fast but they throw in a fascinating kind of music coming from the phase generators commutating the motors driving the train. It is not intentional of course but a great by- product IMO.
And just because this is a thread about nothing.....
An amazing lesson for me was standing on the siding of a German railroad station. All the usual stuff: find out where you want to go, find the train that gets there (or closer at least) buy a ticket, find the particular track and note which way the train is entering and leaving the station (so you are not on the wrong side). You have 10 minutes until the train time, which is departure time. Smoking a cigarette, killing time and it is 5 minutes until 'train time' WHEN SUDDENLY, a train is coming into your slot. Doors open, people get off and people get on, you get rid of the smoke and are just about to step on the door when you notice the train is showing the wrong city. Confusion, consternation and the fact that you may be about to make a mistake in getting on the wrong train, or you may be making a different mistake in not getting on the right train. Only thing to do is back off and pay attention. Train leaves the station and now there are three minutes until the official 'train time' but you figure, as my wife likes to say, "that train has sailed" and you will soon be looking for another way to wherever you are going. But wait, another train is pulling into the station.... and it has the RIGHT destination showing! People get off, people get on (and now I am one of those people) and..... wait for it..... the train leaves the station at the very minute the ticket and schedule said it would . Bottom line, no screwing around with DB (Deutsche Bahn, literally Germany's Train); they run on time, they run often and they run efficiently. Slick system.
Brian
That's cool stuff! Now I wonder what the trade off is versus a more traditional arc weld process.