Whyte Classification of Steam Locomotives

The Whyte notation for classifying steam locomotives by wheel arrangement was devised by Frederick Methvan Whyte[2] and came into use in the early Twentieth Century encouraged by an editorial in American Engineer and Railroad Journal (December 1900). Whyte's system counts the number of leading wheels, then the number of driving wheels, and finally the number of trailing wheels, groups of numbers being separated by dashes.[3] Other classification schemes, like UIC classification and the French, Turkish and Swiss systems for steam locomotives, count axles rather than wheels.

Thus, a locomotive with two leading axles (and thus four wheels) in front, then three driving axles (six wheels) and followed by one trailing axle (two wheels) is classified as a 4-6-2.

Numeric Layout	Wheel Arrangement	Name	Class	Image (click to view)
0-2-2		Northumbrian	Non Articulated Locomotive
0-4-0		Four-Wheel Switcher	Switching Locomotive
0-6-0		Six-Wheel Switcher	Switching Locomotive
0-8-0		Eight-Wheel Switcher	Switching Locomotive
0-8-2			Switching Locomotive
0-10-0		Ten- Wheel Switcher	Switching Locomotive
0-10-2		Union	Switching Locomotive
0-4-0T		Porter	Tank Locomotive
0-4-2T		Little Monster	Tank Locomotive
0-4-4T		Forney	Tank Locomotive
0-6-4T		Forney	Tank Locomotive
2-2-0		Planet	Non Articulated Locomotive
2-2-2		Single, Jenny Lind	Non Articulated Locomotive
2-6-6T		Mason Bogie	Tank Locomotive
4-4-2T			Tank Locomotive
4-6-4T		Baltic	Tank Locomotive
4-8-6T			Tank Locomotive
0-4-0		Camel Back	Light Passenger Locomotive
2-4-0		Porter	2 Wheel Leading Truck
2-4-2		Columbia	2 Wheel Leading Truck
2-4-4		Forney	2 Wheel Leading Truck
2-6-0		Mogul	2 Wheel Leading Truck
2-6-2		Prairie	2 Wheel Leading Truck
2-6-4		Adriatic	2 Wheel Leading Truck
2-8-0		Consolidation	2 Wheel Leading Truck
2-8-2		K-36	2 Wheel Leading Truck
2-8-2		Mikado	2 Wheel Leading Truck
2-8-4		Berkshire	2 Wheel Leading Truck
2-10-0		Decapod or Russian	2 Wheel Leading Truck
2-10-2		Santa Fe	2 Wheel Leading Truck
2-10-4		Texas	2 Wheel Leading Truck
4-2-2		Bicycle	4 Wheel Leading Truck
4-2-0		Jervis	4 Wheel Leading Truck
4-2-4		CP Huntington	4 Wheel Leading Truck
4-4-0		American	4 Wheel Leading Truck
4-4-2		Atlantic	4 Wheel Leading Truck
4-4-4		Reading, Jubilee	4 Wheel Leading Truck
4-6-0		Ten Wheeler	4 Wheel Leading Truck
4-6-2		Pacific	4 Wheel Leading Truck
4-6-4		Hudson	4 Wheel Leading Truck
4-8-0		Twelve Wheeler	4 Wheel Leading Truck
4-8-2		Mountain or Mohawk	4 Wheel Leading Truck
4-8-4		Northern or Niagra	4 Wheel Leading Truck
8-8-8		Breitspurbahn	8 Wheel Leading Truck
4-10-0		Mastedon	4 Wheel Leading Truck
4-10-2		Southern Pacific or Super Mountain	4 Wheel Leading Truck
4-12-2		Union Pacific	4 Wheel Leading Truck
4-4-6-4		PRR Q2	4 Wheel Leading Truck
0-6-6-0		Erie	Articulated Locomotives
0-8-8-0		Angus	Articulated Locomotives
2-4-4-2		Little River	Articulated Locomotives
2-6-6-0		Denver & Salt Lake	Articulated Locomotives
2-6-6-2		H-4-A	Articulated Locomotives
2-6-6-4		Norfolk & Western	Articulated Locomotives
2-6-6-6		Alegheny	Articulated Locomotives
2-8-8-0		Bull Moose	Articulated Locomotives
2-8-8-2		Chesapeake	Articulated Locomotives
2-8-8-4		Yellowstone	Articulated Locomotives
2-10-10-2		Virginian	Articulated Locomotives
4-6-6-4		Challenger	Articulated Locomotives
4-8-8-2		Cab Forward	Articulated Locomotives
4-8-8-4		Big Boy	Articulated Locomotives
2-8-8-2		Beye - Garratt	Special Articulated Locomotives
4-8-8-2		Cab Forward Articulated	Special Articulated Locomotives
2-8-8-8-2		Triplex (Erie RR)	Special Articulated Locomotives
2-8-8-8-4		Triplex (Virginia RR)	Special Articulated Locomotives
6-2-0		Crampton	Non Articulated Locomotive
		Shay-Class A 2 Cyl. 2 Truck	Geared Locomotive
		Shay-Class B 3 Cyl. 2 Truck	Geared Locomotive
		Shay-Class C 3 Cyl. 3 Truck	Geared Locomotive
		Shay-Class D 3 Cyl. 4 Truck	Geared Locomotive
		Heisler 75 Ton 3 Truck	Geared Locomotive
		Heisler 90 Ton 3 Truck	Geared Locomotive
		Heisler 2 Truck	Geared Locomotive
		Climax- Class A 2 Truck	Geared Locomotive
		Climax -Class B 2 Truck	Geared Locomotive
		Climax-Class C 3 Truck	Geared Locomotive