The 500-mile-long 5-county Metrolink commuter rail system removes 8.7 million car trips from freeways annually and the agency has recently invested in Tier 4 diesel locomotives—the cleanest in the U.S.—which are reducing NOx emissions and particulate matter by 85%. Increasing service would further reduce car trips and emissions, but Metrolink’s budget provides only for bare-bones service, mostly during rush hours on weekdays. Moreover, service can’t be expanded on the existing system since most of it is single-tracked, not double-tracked, which means trains can’t pass each other but instead have to turn around, wait and come back—and it’s a long distance from, for example, San Bernardino to Union Station in downtown LA. Providing funding for Metrolink would allow the agency to double-track the rail system, which would allow for more trains and passengers, and further reduce emissions and car trips.

Commuter rail advocates say there’s also low-hanging fruit that if funded could deliver increased ridership and emissions benefits, such as linking tracks through Union Station so the Ventura County train could travel into Orange County, for example, and the Antelope Valley train could connect directly to San Bernardino, etc.—so trains wouldn't have to back in and out of Union Station to get to their destinations. Metrolink is also studying, to cite a specific example, moving the Northridge station from a rather obscure location to Reseda Boulevard, where several bus lines serve many locations including Cal State Northridge and the Northridge Medical Center, which would likely attract significant ridership to the Ventura County Line.