Actions

Relentless Locomotion. The Train cannot have its movement stopped by any non-magical means. Any creature in the train's path must make a STR Save vs the Driver's Animal Handling (DC 15 min). On success, the creature is moved 5ft away from the train and takes half damage. On failure, Large and Smaller creatures are knocked prone and take 58 (5d20) Bludgeoning damage from the engine and 42 (4d20) from each car. This requires no action other than movement, but each car that damages a Large creature reduces movement by 10ft.
Creatures Huge and larger force the train to take the Ram action and are damaged thusly.

Stopping the Train. To stop the train normally, the Driver must expend one of the train's Hit Dice, and succeed on an Animal Handling check, adding 1d20+3 to the roll. The DC to stop the train is its current movement speed.
Casting Dispel Magic on the engine forces the train and all in or on it to make a CON save vs the caster's Spell Save DC. On fail, the train immediately shuts off, and all creatures that failed their save are thrown forward a number of feet equal to the train's movement in the last round and take equivalent falling damage. When stopped in this way, the train cannot be restarted until it succeds a CON Save. Each attempt requires Mending or relevant tools check equal to the Caster's save DC.

Starting the Train. A qualified driver may start the train as an Action. Once started, the train will always use it's full movement speed to advance forward. If the train is on rails, it's speed is doubled.

Ram. As the Driver's Action, The Tank may ram any target within its movement. This attack cannot miss and deals an amount of Force damage equal to any amount of the ship's hit die as decided by the Driver. These die are consumed as if during a short rest and deal damage to both the target and the Tank. Both the Target and the Tank may make a CON save vs the Driver's Land Vehicles (WIS) skill check for half damage. Before rolling, the Driver may decide that both fail this save.