Actually you can cross the entirety of Chile by car if you don't mind taking a ferry that starts in Puerto Montt and arrives in Puerto Natales. It is 4 day trip, but the scenery is gorgeous. Regarding the rail system, Chile had a great rail system that went from Arica to Puerto Montt with lots of spurs going into inner towns. However it was slowly dismantled and now most of the rails are in disuse, or used for the transport of goods. There is still a main rail for passenger transport, but most people prefers taking the bus or driving because of convenience.