metro, interurban

Bari's metro
9 km 9 station metro is run by Ferrotramviaria. It opened in 2008. Ferrotramvia also runs a 70 km interurban line on this same route, with the two lines sharing 4 km of underghround track. As of 2009, 1,5 km of underground extensions are under construction.

This site mentions a new
underground railway station at the airport, which is likely part of the subway which will run from the airport to St. Paul.

Wikipedia page (Italian)
Rail in Bari today with photos
IRA Railfans page
Station models