The PNR Metro Commuter Line was a commuter rail line operated by the Philippine National Railways. It was first inaugurated as the Metro Manila Commuter Service in 1970, and originally served the North Main Line and the South Main Lines, as well as the defunct Carmona and Guadalupe branch lines. Since then, it adopted several names such as Metrotrak and Metrotren, before adopting its present name in the late 2000s. The line was also nicknamed the Orange Line due to its designation in the 1970s.

The Manila Railroad Company (MRR) was a Filipino state-owned enterprise responsible for the management and operation of rail transport in the island of Luzon. It was originally established by an Englishman named Edmund Sykes as the private Manila Railway Co., Ltd. on June 1, 1887. British engineer Horace L. Higgins was then assigned at the helm in Manila as its first general manager. On July 7, 1906, a separate private entity named the Manila Railroad Company of New Jersey was established. The two companies continued to own the Luzon railroad network until February 4, 1916 when the Insular Government acquired both companies and absorbed them into the new Manila Railroad.