Rail transport in Puerto Rico currently consists of a 10.7-mile (17.2 km) passenger metro system in the island's metropolitan area of San Juan.

[2] The new system operated more efficiently,[citation needed] offering more comfortable cars and more stops, including one in the town Market Place (Plaza del Mercado) and another in the Guanajibo neighborhood.

[2] The third operator of the system introduced new larger electric-powered cars, although the service was now limited from the Playa sector directly to the Balboa neighborhood.

It remained active for 13 years, but after a major earthquake hit Mayagüez in 1918, coupled with the recent arrival of the automobile, it was shut down permanently in 1926.

[2] In 1878, engineer-entrepreneur Don Pablo Ubarri was granted a permit to build and operate a 7-mile (11.3 km) passenger steam tramway between the walled city of Old San Juan and the town of Río Piedras.

[3] This interurban system was the beginning of the development of the immediate hinterland outside the walled city, which comprises the northern and central parts of the modern capital municipality of San Juan.

[8] Its origins can be traced back to 1874, when a Spanish engineer proposed building a steam railroad line along the coast of Puerto Rico.

Before its demise, the Puerto Rico railroad system had some 500 kilometers (310 miles) of track and served almost all coastal towns, carrying freight into the Island and transporting agricultural products to the ports for shipping overseas.

Transport by rail greatly improved the everyday life of Puerto Ricans, since passengers could now travel between the largest cities, San Juan and Ponce, in record time.

[citation needed] Previous trips used to take several days by horse and wagons, but the regular train greatly reduced traveling time to around 10 hours.

[citation needed] On the early morning hours of November 7, 1944, the American Railroad Company of Puerto Rico suffered the most violent accident in its history.

3 was traveling from San Juan to Ponce carrying passengers to their different hometowns for the island general elections to be held that same day.

3's ride from Jimenez Station to Ponce was Jose Antonio Roman, an experienced freight train engineer, but who had never worked in passenger travel.

Oscar Valle, an Aguadilla correspondent to the local El Mundo newspaper, summarized the scene in a more dramatic way: "The locomotive suffered a terrible explosion as it derailed, and the impact was so strong that 3 passenger cars were converted into a fantastic mound of wreckage.

[citation needed] The last remaining part of the system used in operations was a small rail line located in the town of Arroyo, which was used exclusively for tourism purposes until 2005.

The Train of the South was an historic, 3 ft (914 mm) narrow gauge plantation line dedicated exclusively for tourism in Arroyo.

Several passenger wagons pulled by a Plymouth WDT 40-ton diesel locomotive transported visitors on an hour-long guided tour along old sugar cane fields.

[22] It first began operations in 1988 under the control of CHEMEX Corporation's predecessor PharmaChem, a supplier of chemicals to Puerto Rico’s pharmaceutical industry, which primarily used the railroad to ship inbound chemical products via a railroad ferry connection from Mobile, Alabama in the U.S. mainland to the marine terminal within the Puerto de Las Américas.

The line's construction started in July 1996 with the purpose of relieving traffic congestion in the San Juan metropolitan area, and was inaugurated January 2005 to mixed reactions.