At least 55 people were hurt, two seriously, when a Metro light rail train and a University of Southern California shuttle bus collided Tuesday along a busy thoroughfare in downtown Los Angeles, officials said.

The crash happened shortly before noon along Exposition Boulevard, near the USC campus and Natural History Museum, according to the L.A. Fire Department.

Two victims were hospitalized with serious injuries and 16 others were transported in fair condition, the department said. Another 37 people were treated at the scene.

Dave Sotero, a spokesperson for L.A. Metro, said the bus crossed into the path of an E Line train. The light rail line runs from East Los Angeles to downtown Santa Monica mostly along streets, and not all of the crossings have gates.