Abstract: It is frequently observed that when a real locomotive starts up, the front set of drive wheels commences to turn before the rear set of drive wheels begins to turn. The present invention is a simple device that permits this effect to be simulated in a model locomotive. The electric motor of the model locomotive drives a worm which turns a first gear. A second gear is mounted on the same shaft as the first gear but is not otherwise connected to the first gear. From the side of the first gear that faces the second gear, a pin extends at a particular radius. Similarly, two pins extend at the particular radius from the side of the second gear that faces the first gear. When the motor starts, the first gear turns immediately, but rotation of the second gear is delayed until the pin on the first gear strikes one of the pins on the second gear. In this way a delayed rotary motion is imparted to the second gear.