Can't repair rail

[Bob12]

My rail repair unit (highlighted in yellow) cannot repair the hex it is sitting on (it has full move). I don't know why this as as to me it seems the rail has a continuous connection all the way back to the border

[No idea]

Hello Bob, when the green circles are dotted that means the rail has been interrupted by some reason (and, when the line is interrupted, you cant keep on repairing it as it doesnt count as continuous connection all the way back to the border). It might be a enemy units ZOC. The problems starts in the first dotted circle. Have in my that perhaps now there is no problem, but there was one in the last turn and thats why I think the rail was interrupted. Never let enemy units ZOC your rails.

PS. By the way, even if your units occupy the rail continuos to an enemy unit, the rail will be considered as ZOCed

[timmyab]

Your rail line is probably in enemy ZOC. You need to protect your rail lines from enemy raids. Cavalry are a particular threat and can move surprisingly quickly even through the marshes.
Most experienced players don't convert the rail lines either side of the Pripit marshes partly because of this threat.

[Bob12]

Haha yeah that was it, nkvd regiment making a nuisance of itself.