Push is an actual Tomorrowland trash bin so named because of the large word "PUSH" found on either flap. The radio control system is hidden by the bin's regular steel liner and plastic trash bag should a guest peer inside.
The robot is discretely operated by a pair of cast members in plain clothes, one with a remote control unit who operates the movement of the robot and the other who provides its voice. (Sci-Fi from Six Flags was operated in the same manner.) The transmitter is hidden inside a large gym bag carried by one of them wherein a voice processor changes the second cast member's voice to a high-pitched, nasal register. Since they are within about 20 feet of the robot, they are able to make Push interact directly with guests and other cast members who are dressed as either atmosphere or face characters.
Exact technical details are uncertain, but the robot appears to be propelled with the transmission, wheels and tires of a mobility scooter, the type of which Disney Theme Resorts rent in large numbers.