A years-long squabble between Denver’s Regional Transportation District and its private-sector consortium for new commuter rail, Denver Transit Partners, has finally landed in court. DTP is suing the transit agency, seeking more money and a change in the law. Federal and state rail safety agencies denied DTP approval for at-grade crossings and quiet zones on RTD’s new commuter rail system. DTP—which includes Fluor Corp., John Laing PLC, Balfour Beatty Rail Inc. and Ames Construction—designed, built and is operating commuter rail for RTD under a public-private partnership. But the line from downtown to the airport has been plagued for years by the inability of train technology to communicate with the crossing gates, thus requiring the ongoing use of human crossing guards at every at-grade intersection. The consortium claims that DTP is not to blame for the increased costs associated with those issues. Another commuter rail line to the Denver suburbs that uses the same train-to-crossing-gate technology is nearly two years behind schedule and has yet to open to commuters. The agency says that DTP has already missed the completion deadline for the entire project, and commuter rail trains continue to sound their horns through street crossings instead of operating under quiet zones as required by the contract. “It has taken DTP not just months, but years to optimize their system to the point where safety regulators are reasonably satisfied,” RTD said in a statement. DTP has not responded publicly about the lawsuit.