The maintenance van seen in the original film was used by the Delos resort robotics staff to transport damaged robots from the Westworld theme park to the repair labs at the park's headquarters. A smaller logo of the original film's Delos resort can be seen on the side of the van.
Behind the scenes
The maintenance van was portrayed by a blue Chevrolet Step-Van, a popular type of light truck from the 1970s. 
Maintenance van arriving at Westworld to pick up damaged robots for repairs
Technicians gathering and loading damaged robots, the street illuminated with portable floodlights
Van departing the town's main street, headed for labs
Van backing up to the damaged robot unloading area