The TrainSim is a computer unit found in Rec Rooms of Terran Confederation capital ships used for training purposes. The bar of the TCS Tiger's Claw had a TrainSim. Pilots there can practice flying and combat techniques against Kilrathi starfighters.
The pilot has to clear consequetive waves of enemy fighters (of the selected type). With each new wave, one more fighter comes. Missions are timed and bonus points are awarded for destroying waves quickly. Pilots who achieve a high score record their name.