[1][2][3] The Los Angeles County Metropolitan Transportation Authority (Metro) has studied two alternative alignments for this extension.

In 2015, Metro estimated the cost of both alignments of what was then known as the Gold Line Eastside Rail Extension at $6.0 billion (to be delivered in 2057).

[15] During the Initial Operating Segment study, Metro concluded that Alternative 1 and 3 would interfere with future SR 60 expansions.

Metro would have to buy some property and remove homes needed for a maintenance facility yard, as no large vacant lots were found.

On April 25, 2024, Metro published the final environmental impact report (EIR) for the project, pending certification from its board of directors.

[16] Metro is also seeking to clear the project under the National Environmental Policy Act (NEPA) to qualify it for federal grant money.