CALIFORNIA - A BART train driver invited a female passenger into the cab at the front of his train, asked her if he could fondle her breasts and then, rebuffed, temporarily blocked her from leaving, authorities said Tuesday.

Contra Costa County prosecutors charged 49-year-old Calvin Peter Tom of Brentwood last week with two misdemeanors stemming from the Aug. 4 incident: soliciting a lewd act in public and false imprisonment.

Efforts to reach Tom were unsuccessful. He has not been arrested but is the subject of a warrant, prosecutors said.

BART spokesman Linton Johnson said the 14-year employee had been placed on unpaid leave after the incident and later resigned.

BART police said the encounter happened about 12:30 p.m. on an eastbound train headed for Bay Point, after Tom invited the unidentified woman and a young boy into his cab. The boy's relationship to the woman was unclear.

Under BART safety rules, passengers aren't allowed in the cabs.

In the darkness of the tunnel between Oakland and Orinda, Tom allegedly whispered to the woman, asking if he could play with her breasts.