This route will continue to be operated by diesel stock but will run at a maximum speed of 160 km/h (99 mph), over twice higher than the existing narrow-gauge line.

The first intercity service on the new Main Line South was the first Bicol Express, which originally only stopped at Aloneros station in Guinayangan, Quezon between 1916 and 1919.

[10] The Main Line South was connected to the Legazpi Division by a fleet of train ferries between Quezon and Camarines Sur.

This ferry service became increasingly redundant as the last rail connecting Manila to Bicol was laid on November 17, 1937.

The second Bicol Express, which at that point had been running the full length of the new Main Line South to Legazpi, was inaugurated on January 31, 1938 and became a regular service by May 8 of the same year.

[11] On the same day, the golden spike was struck by then-president Manuel L. Quezon at Del Gallego, Camarines Sur.

[15] During this period, there were already proposed extensions of the South Main Line to Sorsogon province enacted by Republic Act 6366.

[3] During the enhanced community quarantine in Luzon, the intercity section was temporarily reactivated for PNR's Hatid Probinsya (lit.

'Return to the Provinces') program by the national government to decongest Metro Manila and develop the countryside regions of the Philippines both during and after the COVID-19 pandemic.

On February 14, 2022, Valentine's Day, a regional rail service between San Pablo, Laguna and Lucena, Quezon made its first run.

[23] On June 25, President Rodrigo Duterte inaugurated the Inter-Provincial Commuter service,[24] with operations commencing the following day.

The proposed articulated bus train will occupy five meters on each side of the railway, while the remaining open spaces will be utilized for housing, logistics, public markets, and post-harvest facilities, with transit stations along the way.

[26][27] On July 15 of the same year, it was announced that PNR would revive freight services and pursue a P5 billion plan to retrofit the existing line between Laguna and Albay for cargo movement.

It plans to retrofit the south Luzon alignment for freight rail, potentially benefiting the nearly 600,000 farmers in the Bicol region.

Issues such as rail metal theft and natural disasters have hampered the line's intercity service from operating regularly ever since.

[33] On September 21, 2019, a KiHa 59 and a rerailment train consisting of a newly-repainted PNR 900 class locomotive and a CMC coach conducted a test run from Tutuban to Naga.

[34] The regular Metro South Commuter serves the Greater Manila Area from Tutuban to Alabang in Muntinlupa, Mamatid in Cabuyao, Calamba, or IRRI in Los Baños.

The present South Commuter Line will also be rebuilt and it will serve as an alternate transport mode to the NSCR, as well as for future freight services.

[41] Due to the damages brought by the Typhoon Rammasun (locally named Glenda), PNR announced that the Bicol Express' resumption of services would be further delayed until October and November 2014.

[citation needed] The older Mayon Express Limited service was hauled by the newly-acquired MCBP class DMUs starting in 1973.

It was a JMC class diesel multiple unit built by Tokyu Car Company in 1955 and refurbished in 1973 with a streamlined cab inspired by the likes of the 0 Series Shinkansen.

It became PNR's premium intercity service and also had airline-style features such as pre-recorded background music, snacks, caterers, and stewardesses.

[52] Initially they were non-stop between Paco Station in Manila and Naga City, save for when the Peñafrancia Express trains headed in opposite directions and had to cross each other along the route in Quezon province.

As of 2022, the line uses diesel locomotives and multiple units, as well as passenger coaches built for the 1,067 mm (3 ft 6 in) Cape gauge.

[65] The project was co-financed by the Japan International Cooperation Agency (JICA) and the Asian Development Bank (ADB), and construction began in July 2023.

104 of these are 8-car EM10000 class trainsets that are based on JR East commuter stock such as the E233 series to be built by the Japan Transport Engineering Company (J-TREC).

This would be arranged into 8-car trainsets similar to the NSCR, but are expected to be diesel stock due to the aforementioned lack of electrification on the line.

This replaced a previous order of 9 diesel multiple unit cars from CRRC Zhuzhou Locomotive, which would have been arranged into 3-car trainsets.

[79] The project would have also rebuild the remaining Metro South Commuter section between Tutuban and Sucat sometime after the line's completion by 2025.

The project was originally supposed to be financed by Chinese official development assistance, which was backed out in 2023 due to the failure to act on the loan.