Gunpowder Vans, as their name suggests, transport gunpowder. Because gunpowder is very dangerous, engines must take the most careful way when shunting them, and they are usually put in the middle of trains for safety.
In the model series, the gunpowder vans were based on the Curtis's & Harvey Number 152 gunpowder van used on the Ffestiniog Railway. In the CGI Series, the gunpowder vans have reduced in size, and are based on 2 foot gauge gunpowder vans used to carry gunpowder from Porthmadog to the Blaenau Ffestiniog quarries on the Ffestiniog Railway.
In the model series, the gunpowder vans were painted black with "D. FUSIT" on the sides in white and "GUNPOWDER" underneath in red. In the CGI series, they are painted grey and dark green and have explosives hazard warnings on them.
- The name "D. Fusit" is a play on words of "De-Fuse It".
- The ERTL packaging refers to "D. Fusit" as a male character and implies that he is sentient.