Stepney/Behind the Scenes

Gauge 1 model
Stepney’s model was custom built to run on gauge 1 track for the fourth series. The model was built from brass. It was painted using glossy car body paint and lined with red and gold prostripe automotive tape.

The chassis was constructed from scratch (CNC). It had two motors, both powered by electricity from the track via the pickups on the metal wheels. The main motor powered the wheels, while the second motor (located at the back) powered an inside piston for the smoke mechanism.

The eye mechanism had two servos, one for up and down movement and one for left and right movement. The up/down servo was attached to the body. The left/right servo had a rod attached to the arm, which connected to a bracket. The eye balls were coupled to the bracket and locked in by the face-plate, so whenever the servos were powered, the eye balls would move however the crew member desired.

Ten different facial expressions were worn by Stepney on screen. The faces were first sculpted in clay and from that resin casts were made using a silicone mould.

During the production of the sixth series Stepney’s model was repainted in matte paint.

Close-up model
Close-up shots of Stepney's cab was required for scenes in where he had to interact with close-up scale figures. It was also used for close-up whistle shots; smoke would emit from the whistle when required. The model was not complete and only portions of the cab were built.

It appeared in the fourth, fifth and twelfth series.

Voice Actors

 * Bin Shimada