The system, founded in 1991 as the Southern California Regional Rail Authority (SCRRA) and adopting "Metrolink" as its moniker,[11] started operation in 1992.

In addition to suburban communities and cities, Metrolink also serves several points of interest such as downtown Los Angeles, downtown San Bernardino, Burbank, Hollywood Burbank Airport, Cal State LA, Angel Stadium, and the San Clemente Pier.

[13] Special service has also been extended to the Pomona Fairplex,[14] the Ventura County Fairgrounds,[15] and Auto Club Speedway[16] for certain events.

[19] In late 2018, Metrolink announced that San Bernardino Line ticket prices would be reduced by 25% at least through 2019 in an attempt to increase ridership.

On October 18, 1982, CalTrain, LA's first commuter rail service, began on the existing Ventura County Line, but only lasted a few months before termination, on March 1, 1983.

Senate Bill 1402 was signed into law on May 25, 1990, which directed local transportation authorities to establish a regional plan for commuter rail by the year's end.

[23] In October 1990, the member agencies of the SCRRA had announced the purchase of 175 miles (282 km) of track, maintenance yards, and stations and other property from Southern Pacific for $450 million in 1990 ($1.05 billion adjusted for inflation).

[23][26] Services commenced on October 26, 1992, under contracted operation by Amtrak with the Ventura, Santa Clarita (now the Antelope Valley), and San Bernardino Lines.

The 1994 Northridge Earthquake saw the closure of Interstate 5 and other regional freeways, bringing widespread attention on Metrolink alternatives.

Metrolink experimented with expanded service to Camarillo and Oxnard, and it extended the Antelope Valley line ten years ahead of schedule, rapidly adding six stations in six weeks.

[34][35] Following the 2008 Chatsworth train collision in which 25 people died and 135 were injured a number of safety measures were taken; in the fall of 2009, inward-facing video cameras were installed in locomotives in order to ensure that staff were complying with regulations, in particular a ban on use of mobile phones.

A survey found that 90% of users during a typical weekday in 2009 would have previously driven alone or carpooled and that the system replaced an estimated 25,000 vehicle trips.

[46] Initial plans were for construction/renovation of the line to begin in 2012, but these were delayed by a lawsuit filed by homeowners in the affected area, who challenged the RCTC's environmental report.

The association considered whether to extend commuter rail along the corridor or to install either bus rapid transit or light rail lines,[59] but in December 2015, SANBAG officials said they planned to extend Metrolink service only to the San Bernardino Transit Center and use diesel multiple units operated by Omnitrans in lieu of Metrolink locomotive-hauled coaches on the rest of the route.

[60][61][62] In late 2019, Metrolink assumed the operating rights and carried out construction after Omnitrans was dismissed due to restructuring of that organization.

Although there was speculation that the signals alerting the BNSF to slow and stop had malfunctioned, an investigation later concluded that it was human error by the crew that caused the accident.

On July 8, 2016, the Metrolink board approved a $1.5 million plan to repair the plows on the Hyundai Rotem cab cars.

Such an electrification would be similar to the Caltrain Modernization Program, which also involves electrifying a rail line for eventual use by commuter and high-speed trains.

[77] This alternate plan would provide a "one-seat ride" at the start of service between the Central Valley and downtown, or even Orange County (via Anaheim[78]).

Despite this, the Riverside County Transportation Commission's 2008 Commuter Rail Feasibility Study still lists this route as one possibility being considered.

This extension would likewise require significant money for infrastructure improvements: at least $500 million, according to the California State Rail Plan of 2005.

[90] Nonetheless, in 2013 Caltrans conducted a feasibility study of a Coachella Valley service[92] and RCTC has resolved to pursue establishing one.

[99] The railway, a former portion of the Southern Pacific Coast Line, connects the city of Ventura to Santa Clarita paralleling California State Route 126.

[100] The Santa Barbara County Association of Governments (SBCAG) has announced plans for Metrolink service to/from Goleta to begin in Fall, 2025, starting with one daily trip in each direction.

The facility will serve as an additional site to service Metrolink and Amtrak trains on a parcel of land owned by the Orange County Transportation Authority just north of Irvine station.

[103] OCTA officials are interested in moving the LOSSAN corridor (Los Angeles-San Diego), which carries the Orange County Line and the Pacific Surfliner, from its current alignment inland to avoid service disruptions due to coastal erosion along the route.

Metrolink trains are also serviced at Coaster's Stuart Mesa Facility, which is located between San Clemente Pier and Oceanside at the southwest end of Camp Pendleton.

[6] Until recently, most Metrolink-owned units were painted in a white livery with blue stripes that was introduced in the late 1990s as a replacement for a similar scheme that had been in use since the agency's launch.

Beginning in 2007, the agency began the process of switching to a new blue and green "ribbons" design; the Guardian Fleet and EMD F125 locomotives already arrive from the factory in the new colors.

[38][116] With the introduction of the 2022 rebranding in celebration of the agency's thirtieth anniversary that included a new two-toned blue logo, newly-refurbished rolling stock is currently in delivery wearing these colors starting in 2024.