For many years there were major reductions in long-distance train services in Argentina, but recent years have seen some rail lines progressively reopened. Good sources for information are www.seat61.com/southamerica.htm and www.sofse.gob.ar.
Trains serve most of Buenos Aires and some surrounding provinces. During the holiday periods, such as Christmas or national holidays, buy tickets in advance. Train fares tend to be lower than comparable bus fares, but trains are slower and there are fewer departure times and destinations. Long-distance trains have sleepers.
Train buffs will want to take the narrow-gauge La Trochita, which runs 20km between Esquel and Nahuel Pan. Another legendary ride is Salta’s touristy but spectacular Tren a las Nubes, which at one point spans a desert canyon at an altitude of 4220m – though it's famously unreliable. And finally, the scenic Tren Patagónico connects Bariloche to Viedma.