City Administrator Thomas M. Downs is one of five finalists to head Philadelphia's regional transportation authority, the Philadelphia Inquirer reported yesterday.

Downs, the District's highest unelected official, could not be reached yesterday for comment on the report. Downs, a former executive director of the Urban Mass Transportation Administration, has held his current $71,000-a-year post since 1983.

Downs' name was screened from dozens of candidates by a Philadelphia executive search firm to head the Southeastern Pennsylvania Transportation Authority. The authority, which is the nation's fourth largest, serves Philadelphia and four Pennsylvania counties.

The authority's present general manager, Joseph Mack, announced his retirement in April but will remain until a successor is chosen. The job pays $90,000 a year.

The five finalists for the job are expected to be interviewed this week, and a decision is expected by Nov. 1, the Inquirer reported.

The others were identified by unidentified SEPTA sources as Theodore Weigle Jr., executive director of Chicago's regional tranportation authority; William Stead, general manager of San Francisco's Municipal Railroad system; Frank Wilson, SEPTA's assistant general manager of operations, and Charles Thomas, SEPTA's deputy assistant general manager of operations.