What were they doing to these railroad tracks?

I was visiting my sister. There is a rail line that runs by her house. This is an active line which has daily trains running on it.

But on this day, they were doing something to the tracks. There were several vehicles that traveled down the track on the rails. And the first vehicle was starting fires on the tracks. The second vehicle was following about twenty feet behind the first and we could see the flames between them. The second vehicle was spraying the tracks with water and putting out the fires. Following at some distance behind these two vehicles was another vehicle which was making some kind of pounding noise as if it was driving spikes into the tracks. This last vehicle was following far enough behind the first two that whatever it was doing may have been unrelated to whatever they were doing, other than being scheduled around the same time so they only had to close the rails one time for everything.

My best guess is that they might have been trying to control grass and weeds from growing. But using open flames seems like a strange way to do that.

normally they would use weed killer like roundup to get rid of weeds .

Very likely a track maintenance crew prepare track for repair.
https://farm5.staticflickr.com/4118/4751040014_736b624d98_b.jpgTrack Evaluation Car by Noel Hankamer, on Flickr

I saw this track Evaluation Car stopping at Alvin’s Historic Santa Fe depot Wednesday morning, so I had to stop and get some photos!
This is a Union Pacific car named William E. Wimmer.

My WAG is there may be an accumulation of flammable material on the tracks, so they do control burns to prevent it flaming up from some other cause. The third unit may be just retamping the spikes, a scheduled activity that may not re associated with the fires.

Was there snow or ice on the tracks? If so maybe they were melting the snow and ice around the switches to keep them from freezing and becoming inoperative.

Was it every tie that got this treatment? Were the fires between the ties, and the banging on the ties?

It sounds like some kind of maintenance activity, and I wish I could have seen it to tell you more. It doesn’t sound like full out repair, which usually involves stationary activity.

My first thought is that you saw a rail grinding operation:

...but if you saw flames and not sparks then it sounds like something else

That’s some serious grinding right there. Never seen that before. Thanks for posting.

GaryM

Did you see flames or what may look like smoke from the first one?

While I grew up in an where brush fires would make fires a no go the dust from a ballast cleaner can look like a lot of smoke.

And grinders often spray water.

The third sounds like a tamper, but I would think they would do that before grinding.

I had a friend (now in a nursing home who spent some time working on a railroad track maintenance/evaluation car.

This car went slowly down the track, and did stuff like check exactly the distance between the rails, check for loose rail spikes, verify the quality of the rail & ties, etc. They also did things to repair problems that they noted, like adjust the rails to the proper width, repair or replace loose spikes, etc. (I’m not sure if that was done by the inspection car or another one following behind.)
Major things like rotten ties or long lengths of bad rails required a separate repair crew; they would just de-rate that section of track to a lower speed limit.

What you describe sounds somewhat like what he described this car doing. Except for the burning flames. Weeds used to be controlled with Round-UP or similar chemicals; but the use of them is being restricted more nowadays. Maybe the RR’s have switched to flame-throwers – it’s probably cheaper for them.

Not a RR maintenance expert but, I’ve never witnessed an active rail line that had such a vegetative overgrowth that required a flame treatment as described. This is not to mention the ineffectiveness of such, in this day and age. As others have mentioned, herbicides would address this problem more efficiently and cost effectively than blasting with a torch…

So there must be something else going on here,

Is the OP sure that this was flames they saw?
Could it possibly have been welding of the rail?

I know that rails are often welded into longer, continuous sections now. Especially when they are doing repair, and replacing a short section of bad rail – the replacement is welded to the other rails to form a continuous rail.

Definitely flames. And they were visible between the vehicles so it was not just where the workers were. The first vehicle appeared to be spraying some material on the tracks and setting them on fire. The second vehicle then appeared to be spraying the tracks with water to put out the flames.

Here is one possible reason: This Is Why Metra Sets Its Tracks On Fire In The Really Cold Weather - Downtown - Chicago - DNAinfo

Yeah - it sounds like they might have been retensioning the rails using thermal expansion, then pinning them back down when the tension was all equalised.