Roca Line

The Roca line is the largest commuter network south of central Buenos Aires. Trains connect Plaza Constitución with La Plata, Ezeiza and Cañuelas, Alejandro Korn, and Bosques by two different routes. Shorter outer services reach Monte, Lobos, Chascomús, Haedo, and Juan María Gutiérrez. La Plata also has its own university train.

The network grew from the Buenos Aires Great Southern Railway, which opened its first route from Constitución in 1865. It became the General Roca Railway after nationalization in 1948. The mix of busy electric corridors and lightly used rural branches is still visible in the current service pattern.

Use SUBE for ordinary metropolitan trips. Constitución has separate platform areas and departure boards for the branches, so check the destination before passing the gates. Outer trains run less often and do not offer the turn-up-and-go frequency of the La Plata or suburban electric services.

Modern air-conditioned electric trains cover the main routes. Diesel equipment handles the outer branches and the cross-suburban Temperley to Haedo line. Accessibility is good at many rebuilt stations but not uniform, and rural stops can have low platforms or a larger boarding gap.

The La Plata route follows the river side through Quilmes and Berazategui. The Ezeiza, Alejandro Korn, and Temperley-side Bosques trains share the inner corridor before separating farther south. There is also a second Bosques route through Quilmes, so checking only the destination is not enough when the route through the middle matters.

Tap SUBE at both ends of the trip. A paper ticket costs more, and the correct distance is only calculated when the exit is validated. Trains beyond Cañuelas or Alejandro Korn may have only a handful of departures, with little shelter or staffing at the smallest stops. The Tren Universitario in La Plata is a separate local loop and should be planned from its own timetable.