...Trains,...

Sorry, no actual trains, but plenty of vehicles with tracks.

First up in the tracked section is the Piston Bully.  Primarily used by the science groups, these vehicles are used for getting around the area surrounding McMurdo where there are no groomed roads for wheeled vehicles to use.  While slow on dirt and ice, once the tracks get out on the soft snow they can really fly, though o real suspension to speak of.  There is some IT and coomunications equipment at the top of Crater Hill and the incline is so steep you can only take a Piston Bully or walk up the path.

A Hagglunds Bv206, also used primarily by the science groups when more cargo capacity than a Piston Bully is needed.

A Caterpillar bulldozer.  It's use should be self explanatory.

One of the Fire Department's runway trucks on Mattracks.

A Tucker Sno Cat out at Byrd.  There were a few of these out at Byrd used primarily for grooming the snow around camp.  A couple ended up as part of the PIG traverse when two of the traverse Challengers broke down.

A Caterpillar Challenger.  Though primarily used for the South Pole and PIG traverses, they end up seeing use out at the runways (both at McMurdo and field camps) for grooming.

A Case IH Steiger.  Like the Challenger, it is primarily used for the South Pole traverse.  Interesting trivia bit: at the time of writing, the image on the Wikipedia page for the Case STX Steiger was taken at McMurdo.

For those keeping track, no John Deere equipment to be found.  It must not be robust enough for the environment. :)

Finally, though not an official vehicle, this cross between a snow machine and motorcycle was a winter over project from previous years.

Not pictured are the assortment of snow machines used primarily by science groups and field camps for short trips that don't require the capacity afforded by a Piston Bully or moving light cargo.  In some cases, sciences groups will do short, multiday expeditions on them.