Locomotive Wheel Arrangement and Types

Whyte

System

Symbol

Front to Back Type
0-4-0 oo 4-wheel switcher
0-6-0 ooo 6-wheel switcher
0-8-0 oooo 8-wheel switcher
0-8-8-0 oooo oooo Mallet *
0-10-0 ooooo 10-wheel switch.
     
2-6-0 oUUU Mogul
2-6-2 oOOOo Prairie
2-6-6-2 oOOO OOOo Mallet *
2-6-6-4 oOOO OOOoo Mallet *
2-6-6-6 oOOO OOOooo Allegany
     
2-8-0 oOOOO Consolidation
2-8-2 oOOOOo Mikado
2-8-4 oOOOOoo Berkshire
2-8-8-0 oOOOO OOOO Mallet *
2-8-8-2 oOOOO OOOOo Mallet *
2-8-8-4 oOOOO OOOOoo Yellowstone*
2-8-8-8-2 oOOOO OOOO OOOOoo Triple *
     
2-10-0 oOOOOO Decapod
2-10-2 oOOOOOo Santa Fe
2-10-4 oOOOOOoo Texas
2-10-10-2 oOOOOO OOOOOo Mallet *
     
4-4-0 ooOO American
4-4-2 ooOOo Atlantic
4-4-4 ooOOoo  
4-4-4-4 ooOO OOoo 4-cyl **
4-4-6-4 ooOO OOOoo 6-cyl **
     
4-6-0 ooOOO 10-Wheel
4-6-2 ooOOOo Pacific
4-6-4 ooOOOoo Hudson
4-6-4-4 ooOOO OOoo 4-cyl **
4-6-6 ooOOO OOO Tank
4-6-6-4 ooOOO OOOoo 4-cyl *
     
4-8-0 ooOOOO 12-Wheel
4-8-2 ooOOOOo Mountain
4-8-4 ooOOOOoo Northern ***
4-8-8-2 ooOOOO OOOOo Mallet *
4-8-8-4 ooOOOO OOOOoo Mallet *
     
4-10-0 ooOOOOO Mastodon
4-10-2 ooOOOOOo Southern Pacific
     
4-12-2 ooOOOOOOo Union Pacific
     
* = Mallet articulated  
** = Not articulated  
*** = Aka-Niagra / Pocono  
Source: [AARQJ]