Keolis's tenure as operator of the MBTA's Boston-area Commuter Rail network is entering its final stretch, and competing suppliers are now fighting over which of them will run the next contract on one of the largest commuter networks in the United States.

The Boston Globe reports that with the current Keolis deal ending, rival operators have begun positioning themselves for the successor agreement. The contest comes at a moment of intense scrutiny for the network's performance, its cost base and its long-term expansion ambitions.

Keolis has held the Commuter Rail operating contract since 2014, when the French-led group took over from MBCR. Over that period the franchise has carried hundreds of thousands of daily passengers across a network of more than a dozen lines radiating from Boston's North and South stations, serving communities across eastern Massachusetts.

The upcoming rebid puts three broad questions in front of the MBTA and Massachusetts policymakers: who can run the trains more reliably, who can do it at lower cost to the public purse, and who can support the region's expansion agenda — including long-standing proposals for more frequent regional-rail style service.

For the incumbent, the end of the contract means defending a record that has mixed operational recovery with persistent friction over performance and penalties. For challengers, it offers a rare opening: big US commuter operating contracts change hands infrequently, and winning Boston would deliver a flagship reference in the North American market.

The MBTA's procurement process will test each bidder's claims against the realities of an aging fleet, constrained infrastructure and demanding on-time performance targets. Trade observers will be watching whether the agency uses the competition to extract stronger service commitments, revised fee structures or deeper investment obligations than the outgoing deal contained.

Award of the next contract will shape the operating model for Greater Boston's regional rail for the better part of a decade. A decision is expected as the current agreement runs toward its conclusion, with the Globe's reporting signaling that the fight among rivals is already underway.