The world’s longest light rail line is about to get even longer

A date has been officially set for the grand opening of the latest expansion on the LA Metro A Line.

On Sept. 19, the A Line will be extended about nine miles from its current northern terminus in Azusa to Pomona, with new stations and stops in Glendora, San Dimas and La Verne.

The A Line currently runs a length of 48.5 miles, making it the largest light rail line in the world. This latest extension, followed by another eventual expansion into San Bernardino County, will help the line maintain that title for the foreseeable future.

Previously, the A Line segment north of Los Angeles Union Station was called the Gold Line, and later, the L Line. At the time, the A Line, previously the Blue Line, was a far cry from holding the crown of the longest light rail line in the world.

In June 2023, after LA Metro completed the regional connector project, which created three new underground stations and led to the realignment of both the A Line and E Line, the L Line was retired and split between those lines to create the city-spanning rail system we know today.

The northern extension of the LA Metro line has been in the works in various forms for more than 25 years, including arriving in Pasadena in 2003, and construction beginning in 2010 to extend the then-Gold Line from Pasadena to Azusa.

This portion of the ongoing extension project began with construction kicking off in July 2020. In addition to the several new stations built, it also includes the construction of 19 bridges, 21 street crossings, new parking facilities and more than 10 miles of sound walls made from half-a-million recycled tires.

The line’s expansion was funded primarily by L.A. County’s Measure M half-cent sales tax, along with state grants and Measure R funds.

This latest completed segment is considered Phase 2B1, with the final extension to Montclair dubbed Phase 2B2. Both phases were initially planned to be completed simultaneously but were eventually split due to funding reasons.

Unlike other LA Metro projects, the Foothill Extension is overseen by the Foothill Gold Line Construction Authority, an independent transit agency that handles the design, construction and logistics of the build before handing the project off to LA Metro upon “substantial completion.” LA Metro has been testing the system and training operators since January.

The Authority has boasted that its projects have been delivered on-time and on- or under-budget, although there is some skepticism about those claims.

Issues have surrounded the final phase of the extension from Pomona to Montclair.

Only one construction firm submitted a bid for the project, and its estimate was hundreds of millions of dollars higher than the Authority’s budget. In April, it was announced that the Authority would revise its plans and seek new bids to complete the last and final portion of the project.

The Montclair extension would add an additional 3.2 miles to the A Line’s overall length, extending the world’s longest light rail line to about 60 total miles.