Tracks, ties and ballast painted white: why?

On a trip on the New Haven Line today, I noticed some areas of track (and ties and ballast) that have been painted white; perhaps a 7'x7' area, covering everything, is painted white here and there.

Why? Is the white paint just marking an area that needs maintenance or something?

Do other railroads do this?

Thanks.

Could have been a heavy spray of Weed killer to stop weed growth,in areas that create trouble in the fall.
Just about every RR has a weed/brush control program of some sort.

Probably to let everybody concerned, including Bridge & Building people, the location of a drainage pipe under the rail. On some railroads the B&B guys are tasked with their inspection.
Just a guess,mind you.

Was the area you saw "painted white" on concrete ties?

May have been dust from the ties wearing down underneath...

In my experience, it is just as Freddy says: "There's a culvert here". Because when your culvert gets clogged up, and the water is flowing OVER the tracks, and you forgot where every one of your culverts is, it's nice to see that big white marker.

no culvert, just mud spot, concrete ties start pumping and start disintegrating from bottom.
the water and concrete mud sprays everything in surrounding area white.

Well THAT is an interesting theory, but from the US-11 overpass west of Potsdam, NY, you can look railroad south and see a white-painted wooden tie sitting on top of a culvert. Maybe it's a CSX thing?

hope so, as MN does not go to Potsdam, and does not paint ties for culverts.