The contract, which includes rolling stock maintenance, is worth $US 21m in the first year with an option for a further five-year extension, which would start in 2020.

Keolis has operated VRE trains since 2010, during which time customer service scores have risen sharply and on-time performance has shown continuous improvement, the company says.

VRE serves 18 stations on its two-line network and operates 29 services a day with average weekday ridership of 19,000. The rolling stock fleet comprises 20 MPI MP36 diesel locomotives and 93 coaches.