Bidders shortlisted for upgrading the Plovdiv-Bourgas railway line in Bulgaria April 28, 2010 | Europe News The National Railway Infrastructure Company (NRIC) of Bulgaria has shortlisted three companies for upgrading the Plovdiv-Bourgas railway line. The shortlisted companies are France-based TSO, a consort... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password