There is the overground train - multiple companies run these, and can be used for going from Retiro to Belgrano or as far as Tigre.
There is a direct train from the Retiro station to Estación Tigre. Takes under 50 minutes for the trip and the last station is at the center of Tigre and the fare is AR$1.10 [2008], and it runs quite frequently. If you have the larger paper-back sized Guia-T, it has a map of Tigre.
Estación Tigre is at the main part of the town, and it also has the launching areas for many boat companies for a trip through the delta. This place also has many restaurants, and tourist attractions.
There is also another train called the Tren de la Costa which goes from Maipú–Bartolomé Mitre station in Buenos Aires to Estación Delta. To get to Bartolomé Mitre take a train from Retiro, the ride costs AR$0.65 and takes under 30 minutes and the last station is Bartolomé Mitre on that line. At that station walk over the connecting bridge to the Maipú station, and take the Tren de late Costa from Maipú.
This train will end at Estación Delta which is just two minutes from the coast-line, and a 10 minute walk to the Estación Tigre area which has a large number of boat launches, restuarants. The Tren de la Costa is a tourist train that has scenic stations along the way. The one way ticket is AR$8 and it allows you to get off and and on at every station on the route, and the train usually runs every 30 minutes, taking around 40 minutes for the full ride.
On the Tren de la Costa, two stations are worth stopping by: Anchorena and San Isidro. Anchorena is adjacent to a large unspoiled green park with no shops and on the banks of the river. It has some trees to sit under for a nice picnic on the river. San Isidro has shopping, crafts, and food right at the station. It also has a nice park just outside the shopping center.
[March 2008]