Engineers and conductors for Southern California's commuter rail service are threatening to boycott new personality tests required after a crash in 2008 that killed 25 people.

Two railroad unions objected to the agreement between Metrolink and its new contractor, Amtrak, because it would require crews to pass tests to keep their jobs, according to a Los Angeles Times report published Wednesday.

The "personality inventory" for engineers is designed to test work habits and seek out what are labeled "focused introverts" who are good at repetitive tasks and don't become distracted while operating a train, according to an Amtrak statement.

Union leaders said Amtrak may not be able to find qualified train crews when it takes over operations of the 500-mile system this summer. Amtrak has required its employees to take the screening tests since 2002.

Metrolink's board said it might revisit the tests, which many corporations use to evaluate job applicants.

The written tests are part of an effort to improve safety, Metrolink officials said.

The switch to Amtrak came after the current operator, Connex Railroad, did not pursue a contract extension following the Chatsworth crash, which has been blamed on Metrolink engineer Robert Sanchez, who repeatedly violated safety rules by texting while operating trains.

Federal investigators found Sanchez sent texts seconds before he ran a red light and hit a freight train head-on.

Union leaders argue that the tests are not relevant measures of a trained and experienced employee's ability to safely operate trains. They said existing train crews to pass the tests could arbitrarily cost good workers their jobs.

"I think it's strictly a witch hunt," said Tim Smith, California legislative chairman of the Brotherhood of Locomotive Engineers and Trainmen.

Conductors union representative Ray Garcia said longtime Amtrak employees who've never taken the personality tests would be allowed to transfer to Metrolink under the new contract.

___

Information from: Los Angeles Times, http://www.latimes.com