Hitting Russian Railways.
I am led to believe one of the main problems of hitting the railways through sabotage is the tracks are quite easily repaired, with minimal machinery.
Taking out a section of the railway usually doesn't stop the trains being re-routed.
To stop that you need multiple sabotage teams over a wide area.
The risk of hitting a section in a remote area, is that its remote...so the team has to get to the remote area undetected and exfil.
That can only be done once or twice without people becoming suspicious.
Moving to a new area is easier said than done, if your face is new in an area again you are a target and you don't know the lay of the land.
Hitting the railways works best when the general populace is involved and or on your side.
As we have seen a great many Russians are in favour of the SO.