I am wondering if there are any railroads in Antarctica. Maybe on research stations, even those shorter than 1km?
There are very few mentions of railways in Antarctica. According to this webpage by Glyn Williams, a train enthusiast, there used to be one railway in the French Dumont d'Urville station, used on a very short distance to transport supplies.
On the same page and on some others, there are mentions of multiple places in the far South with former railways. For example, we can see pictures of an abandoned locomotive on the South Georgia island from a very well documented website:
Interestingly, the carrying of the supplies on the continent is assured by long convoys that really look like trains (on snow). You can check out this video or that website: