A system incorporating a robot to inspect ferrous surfaces. Preferably, the robot is an articulated device having a tractor module for motive power and steering, a power module for electrical power and communications and additional motive power, and a third module for cleaning and inspection. The robot uses sensors and generates and transmits signals to a computer through a tether and receives direction from an operator via the computer and tether. The computer continuously monitors the location of the robot and supports the robot during deployment. In a specific application, the robot travels the interior of a tank on a set of magnetized wheels. Prior to inspection, the tank surface is cleaned of deposits by rotary cutters and rotary brushes on the third module. The robot obtains thickness measurements via onboard ultrasonic transducers that contact the cleaned surface. A method for implementing inspection of ferrous surfaces is also described.