Plasser has an ad on page 21 in the February issue of the magizine for their on-line flash welding equipment that looked interesting.
They have a video of the pictured unit in a hi-rail version on their site.
There is also a video of an on-track unit as well.
A different unit with a UP emblem has its interesting video.
Not so spectacular as a thermite weld but perhaps a little better, especially to the extent that the weld can be verified at the time of “making the joint” as it were.