Plans to build railways south of Manila were realized during the American period. The two main lines were the Cavite Line (Paco-Naic), and the Main South Line and its branches (which ends at Legaspi, Albay).
Branches connected Batangas and Laguna (Santa Cruz and Pagsanjan) to Manila. The last addition to the line was the Carmona-San Pedro railway line in the 1970s.
By then the once vast railway network had fallen into disrepair and mismanagement, made worse by competition (and preference ) with cars and highways.
The line is barely alive today.
The South Luzon Railway System
Although the Spaniards had already planned railways south of Manila, it was during American rule these were eventually built.
The first line went from Tutuban to Paco, where a new station would later be built. Another line went to Naic, Cavite. The line was gradually extended south, to Batangas, Laguna, and Tayabas.
Further south, work on railways across Bicol were also started. The Manila Bicol railways were finally joined in 1938. The last addition to the South Luzon railway network was the Carmona line, built in the 1970s.
By then the railways were already in a steady decline, suffering from mismanagement and competition with highways. Most of the south line and its branches are now defunct or used sparingly whenever the PNR launches a short lived attempts to activate the railways.