The Train of the South — or Tren del Sur in Spanish — is a historic 1,000 mm (3 ft 3+3⁄8 in) narrow gauge heritage railroad operating within the U.S. commonwealth of Puerto Rico in Arroyo.

After a temporary shutdown in 1988, former Arroyo's mayor Reinaldo Pirela obtained funds from Puerto Rico's government to refit tracks and the transfer of eight Plymouth locomotives from Central Aguirre's stock to restart successful operations in 1996.

As a result of past unaccomplished promises of financial assistance from Puerto Rican Legislative and Executive Branches, mayor Figueroa signed a contract with Progressive Southern Railway Inc. (a local company just incorporated in 2005[13]) to refurbish and manage the Tren del Sur.

When Progressive Southern Railway took control of the Tren del Sur assets in November 2005 under the premise that the "rails needed to be refitted", they dismantled nearly all of the tracks along the 4-mile (6.4 km) route to "send to the United States for refurbishment"; after this, the historical train never resumed operations.

In 2011, the Arroyo Municipality realized that the lawsuit costs were too expensive, and settled paying $100,000 to Progressive Southern Railway Inc.[14] [15] A number of vintage and historic rolling stock equipment exists around the grounds of the Train of the South.