Trains = Trenes, Buenos Aires
THE TRAIN, The best for middle long distances. Preferably take only the TBA lines because the other lines go to places where turists shouldn´t go at all.
You can see the schedules at www.tbanet.com.ar
If someone advise you to take a train from RETIRO… there are actually 3 train stations : Belgrano, Mitre and San Martin.
Establish which train stations before heading out there.