Youll often see cars run wide if they pick up dirt or dust with slick tires. Youll also often see rubber pebbles lying next to the racing line as seen here. Twitter link. After a race drivers are told to pick up rubber to make the car a tiny bit heavier to avoid being umderweight, which will lead to the tires looking completly gone.
If you want to see what happens with wet tires on a drying track look at “Slicktermediates” wich kinda look like the ones in the OP.
Sometimes youll need stuff like this. Rail maintenance cant always be done using overhead lines, since the machines will get destroyed by electric breakdown(?).
Some parts are not electrified yet, some cant be without major work being done to the track.
It is not ideal, but sometimes you cant do it otherwise, or you’d have to cut of some parts, imo its a useful way to bridge gaps.