Muir is an old 2-6-0 or an American Mogul type steam locomotive in Planes: Fire & Rescue who works at the Piston Peak National Park.
In Planes: Fire & Rescue, he is seen puffing along a train track as Dusty Crophopper flies past him.
- Unlike the steam train seen in Planes, Muir's mouth is on the front of his smokebox door instead of his cowcatcher.
- These types of engines were used most common on American railroads during the 1800s and 1830s until 1928.
- Muir is likely based on a locomotive that worked on the Virginia & Truckee Railroad.