> But there are fewer than handful of railway lines crossing over the eastern border to Russia. Those can be blown up for good, for long enough distance that it

> But there are fewer than handful of railway lines crossing over the eastern border to Russia. Those can be blown up for good, for long enough distance that it's not feasible for Russia to rebuild track and reconnect to the main network should they ... There is no such thing as "blown up for good" for a railway line. And similar for "not feasible for Russia to rebuild". Destroying enemy-held (or soon-to-be-captured) rail lines was a thing, at scale, in WWII. On the Russian Front. Similar for rebuilding captured rail lines to convert them from "enemy gauge" to "our gauge". At best, using a different gauge and rail destruction are delaying & resource-draining tactics.