[odawg]

From Wikipedia: It is widely and incorrectly believed that Imperial Russia chose a gauge broader than standard gauge for military reasons, namely to prevent potential invaders from using the rail system. In 1841 a Russian army engineer wrote a paper stating that such a danger did not exist since railways could be made dysfunctional by retreating forces.[citation needed] Also the construction of the Warsaw–Vienna railway in 1,435 mm (4 ft 8 1⁄2 in) was precisely so it could be connected to the Western European network, in that case to reduce Poland's dependence on Prussia for transport. Finally for the Moscow - Saint Petersburg Railway, which became the benchmark, the choice of track gauge was between 5 ft (1,524 mm) and the wider 6 ft (1,829 mm), not standard gauge 1,435 mm (4 ft 8 1⁄2 in).[6] Despite this the difference in gauge did play a role in hindering invading armies, especially in World War II (see Operation Barbarossa#Faults of logistical planning); it was just not selected with that in mind.

[Natufian]

Thanks for that, interesting stuff. Not a lot to do with your question or my answer but interesting just the same.