Los Angeles ? A head-on collision that left 25 people dead has brought new scrutiny to the safety of Southern California’s regional rail service – a system that has logged more fatalities than any similarly sized system in the nation in recent years.

The catastrophic collision of a Metrolink commuter train and a Union Pacific freight train last week also prompted calls for national safety reforms.

Gov. Arnold Schwarzenegger wants a review of state and federal rail oversight, and Congress is considering compelling railroads to install satellite-linked technology that can detect runaway trains and put on the brakes – an idea that has languished for years.

Two statistics put Metrolink at a disadvantage relative to other commuter-rail systems when it comes to safety: It has far more street-level crossings than similarly sized railroads, and must share tracks with freight trains more frequently than any of its peers.

“Southern California has the most high-risk track in America,” said Sen. Dianne Feinstein, D-Calif. “How can you put commuter trains on the same track as freight trains – going in opposite directions – with nothing more than a signal that can be missed, and has been missed, to avert disaster?”

Records and official reports show at least 74 people have died in Metrolink accidents since 1998, not including the 25 killed Friday along a horseshoe-shaped stretch of track in suburban Chatsworth.

Many of the accidents involved trespassing by cars or pedestrians who sidestepped warning signals or took shortcuts across tracks. Some were suicides.

A 2006 federal study of commuter rail said accidents dropped nationwide between 1996 and 2005, despite a surge in passengers. Fatalities, it said, remained relatively stable, averaging 78 a year.