Soffiante e tirafumo

La quantità di ossigeno presente nell'aria determina l'intensità con cui il combustibile brucia e, di conseguenza, la temperatura all'interno del forno della locomotiva a vapore.

The primary way to feed air to the firebox is by opening the regulator and cutoff fully and propelling the vehicle. As the steam is expelled cylinders out into the atmosphere through the chimney, with every gear cycle, it creates a vacuum in the firebox, drawing in fresh air.

Inoltre sono presenti due meccanismi di controllo progettati per regolare il tiraggio, ovvero il soffiante e il tirafumo.

Blower is usually operated by a valve. When open, it releases steam from the boiler to the chimney. This creates some vacuum in the firebox, drawing in fresh air. However, since this airflow is vastly inferior to acceleration airflow, the blower is only efficient to use when stationary.

Damper is usually operated by a lever. When closed (pushed down) it chokes the airflow whatsoever, drastically reducing fire temperature, even if the vehicle is accelerating. This is used to intentionally cut steam production when it is no longer needed.