SEPTA violated state law when it hired a private company to operate Owl Link shuttle buses, a new on-demand service for workers on the late shift at warehouses and other job sites in Lower Bucks County, the transit workers union says in an unfair labor practice complaint.

The transit agency did not bargain with Transport Workers Union Local 234, which represents bus operators, before making the change, as required by the state’s labor law covering public employees, the union says.

“This is a way of opening the door to contracting out more of our work,” Willie Brown, president of TWU Local 234, the transit system’s largest employee union, said Wednesday. “We’re going to fight with everything we have to preserve our members’ jobs.”

Owl Link, which carries the SEPTA brand, is a pilot program with Via, a global transportation company that developed the smartphone app and scheduling software that runs the service.

It was designed to carry workers to and from the northernmost stops on existing bus routes and the distribution businesses that have sprouted in Bucks County since the interchange between I-95 and the Pennsylvania Turnpike was completed.

SEPTA has not yet received a copy of the complaint and can’t respond in detail, spokesperson Andrew Busch said, but officials did brief the union about the Owl Link before it launched May 10. He said it is similar to other services operated by contractors, such as paratransit for people with disabilities.

The dispute is significant because transportation experts, including SEPTA’s own planners, say public transit needs to add such flexible options to survive amid changing travel patterns, expected to accelerate after COVID-19. It also seems to reflect growing tension between TWU and the agency ahead of bargaining over a new contract.

“It’s no time for SEPTA to mess with the union,” said Bruce Bodner, TWU Local 234′s counsel, calling the hiring of a contractor a “provocative action.” The union’s contract expires Oct. 31.

The Owl links to three 24-hour SEPTA bus routes — the 14, 56, and 66 — so riders can access the rest of the transit system. It operates daily from 10:30 p.m. to 6 a.m., between Horizon Boulevard, the City Line Loop and the Torresdale-Cottman Loop and a variety of job centers spread in Bucks County.

Regular SEPTA bus service in the county stops at 10 p.m.

Trips on the shuttle service are free, though passengers are asked to present a SEPTA key card. Easton Coach operates the buses on a one-year contract with the authority.

It works somewhat like Uber or Lyft, though not quite as open-ended. All rides on the 14-person buses are shared, with passengers dropped off and picked up at stops as close as possible to their workplace. Customers book a ride on the app at least 30 minutes in advance; they are directed where to meet the bus and can track its progress.

TWU also filed a grievance charging that SEPTA violated the terms of its collective bargaining agreement, Bodner said. That will be heard by an arbitrator, while the unfair labor practice complaint will be considered by the Pennsylvania Labor Relations Board.

Though the Owl Link is designed to close a gap in SEPTA service, there is no reason the shuttles can’t be driven by union members, Bodner said.