Wrong the rail line is the means by which military support is moved, Russia has a history of utilizing rail as their supply lines.
"The reason Russia is unique in having railroad brigades is that logistically, Russian forces are tied to railroad from factory to army depot and to combined arms army and, where possible, to the division/brigade level. No other European nation uses railroads to the extent that the Russian army does."
"Trying to resupply the Russian army beyond the Russian gauge rail network would force them to rely mostly on their truck force until railroad troops could reconfigure/repair the railroad or build a new one. Russia’s truck logistic support, which would be crucial in an invasion of Eastern Europe, is limited by the number of trucks and range of operations."
https://warontherocks.com/2021/11/feeding-the-bear-a-closer-look-at-russian-army-logistics/
"Russia has to defend in 360°. It is heavily dependent on barge and rail movement. It does not have the manpower of Soviet times. It cannot be strong everywhere at once and has gone to highly mobile brigades so that it can rapidly assemble forces where needed."
"The vast majority of personnel and cargo are transported via
rail for civil and military purposes. Rail transport is the primary means of logistical support for most military operations (including current operations
in and around Eastern Ukraine) and is an absolute necessity for any type of large-scale movement throughout the great expanse that is the Russian Federation"
"Due to the importance of rail for military operations, the Russian Federation has a separate branch, the Railroad Troops, dedicated to protecting, servicing, and maintaining rail service in combat and austere conditions for the Russian Armed Forces."
https://www.armyupress.army.mil/Portals/7/Hot%20Spots/Documents/Russia/2017-07-The-Russian-Way-of-War-Grau-Bartles.pdf