SAN DIEGO – Union Pacific and autonomous trucking company TuSimple have delayed plans to begin driverless truck moves between the railroad’s Tucson intermodal terminal and the Phoenix area.

The companies in February said they’d launch the service this spring. But the service has been pushed to the third quarter because TuSimple and UP have shifted their focus to hauling containers, rather than trailers as initially envisioned, TuSimple executives said during the company’s earnings call on Tuesday.

UP will become the first customer to move freight on TuSimple’s fully automated trucking route between the Tucson and Phoenix metro areas. UP subsidiary Loup Logistics will coordinate the moves between rail and the first and last mile.

TuSimple, which conducted its first driverless revenue move in December, operates a network of autonomous trucking routes in the Southwest. Previously the company made revenue moves with a “safety driver” aboard to take the wheel if necessary.

TuSimple says global supply chain problems have forced it to delay production of an autonomous rig that Navistar will build in Mexico. The companies planned to begin building the Level 4 autonomous rigs in 2024, but now are aiming for 2025.

Commercialization of TuSimple’s autonomous freight network does not depend on production of the Navistar rigs, the company says. Rather, it will continue to rely on rigs retrofitted with TuSimple technology.

UP invested in TuSimple in 2020. Canadian National also has invested in the autonomous trucking startup.