From south to north, the Green Line starts at Winchester station in Campbell and heads northeast towards downtown San Jose, paralleling the Union Pacific Permanente branch.

It was originally scheduled to open two months earlier on August 1 but was delayed due to a dispute between Federal Railroad Administration and VTA.

At issue was whether a waiver was needed from FRA, since the Union Pacific branchline that parallels most of Vasona extension is still actively used on a tri-weekly basis to serve the Permanente Quarry cement plant in the Cupertino Foothills and a lumber yard in Campbell.

A waiver was finally obtained on the condition that all light rail vehicles sound their horns at crossings until "Quiet Zone" improvements are implemented.

In 2014, a new storage track and crossover was constructed between Old Ironsides and Reamwood as part of improvements to support events at Levi's Stadium and the future Silicon Valley BART extension.

As of early 2019, station signage has begun to reflect the future configuration, displaying line colors rather than terminus icons.