机车轴式
（重定向自轴式）
在铁路技术上，机车轴式，或称机车轮式，是指用英文字母和阿拉伯数字的组合来表达铁路机车走行部车轴排列结构和特点的系统化分类方式。世界上各地使用的机车轴式表达系统主要有三种。
- 华氏轮式：这是最早出现的机车轴式分类系统之一，广泛应用于蒸汽机车的识别，主要为美国、加拿大、英国、爱尔兰等地采用。
- AAR轴式：是一种由美国铁路协会所制定的轴式分类法，主要应用于美国和加拿大的柴油机车和电力机车。
- UIC分类法：是一种由國際鐵路聯盟制定的轴式分类法，广泛应用于欧洲和亚洲国家。
不同机车轴式之對比 编辑
UIC軸式
VDEV/VMEV/UIC-System華氏式別
（Whyte-Notation）美式稱呼 簡單圖解
左方為機車前進方向A1 0-2-2 Oo A2 0-2-4 Ooo 1A 2-2-0 Planet oO 1A1 2-2-2 Patentee oOo 1A2 2-2-4 oOoo 2′A 4-2-0 Crampton, Norris, Jervis ooO 2′A1 4-2-2 Single Driver ooOo 2A2 4-2-4 ooOoo 3A 6-2-0 Crampton oooO N/A 0-3-0 OOO B 0-4-0 Four-Wheel-Switcher OO B1 0-4-2 OOo B2′ 0-4-4 Forney OOoo B3′ 0-4-6 OOooo 1B 2-4-0 Hanscom oOO 1′B1′ 2-4-2 Columbia oOOo 1B2′ 2-4-4 oOOoo 1B3′ 2-4-6 oOOooo 2′B 4-4-0 American, Eight-Wheeler ooOO 2′B1′ 4-4-2 Atlantic ooOOo 2′B2′ 4-4-4 Jubilee ooOOoo 2′B3′ 4-4-6 ooOOooo C 0-6-0 Six-Wheel-Switcher OOO C1 0-6-2 OOOo C2′ 0-6-4 OOOoo 1′C 2-6-0 Mogul oOOO 1′C1′ 2-6-2 Prairie oOOOo 1′C2′ 2-6-4 Adriatic oOOOoo 1′C3′ 2-6-6 oOOOooo 2′C 4-6-0 Ten-Wheeler ooOOO 2′C1′ 4-6-2 Pacific ooOOOo 2′C2′ 4-6-4 Hudson, Baltic ooOOOoo D 0-8-0 Eight-Wheel-Switcher OOOO D1 0-8-2 OOOOo D2′ 0-8-4 OOOOoo D3′ 0-8-6 OOOOooo 1′D 2-8-0 Consolidation oOOOO 1′D1′ 2-8-2 Mikado oOOOOo 1′D1′ 2-8-2T MacArthur oOOOOo (1′D1′)(1′D1′) 2-8-2+2-8-2 Double Mikado, Garrett oOOOOo+oOOOOo 1′D2′ 2-8-4 Berkshire oOOOOoo 1′D3′ 2-8-6 oOOOOooo 2′D 4-8-0 Twelve-Wheeler, Mastodon ooOOOO 2′D1′ 4-8-2 Mountain, Mohawk (NYC) ooOOOOo 2′D2′ 4-8-4 Northern, General Service (SP), Golden State (SP), Niagara (NYC), Wyoming ooOOOOoo 2D3 4-8-6 ooOOOOooo 3′D3′ 6-8-6 nameless (Pennsylvania Railroad Steam Turbine) oooOOOOooo E 0-10-0 Ten-Wheel Switcher OOOOO E1′ 0-10-2 Union OOOOOo 1′E 2-10-0 Decapod oOOOOO 2′E 4-10-0 Mastodon ooOOOOO 1′E1′ 2-10-2 Santa Fe oOOOOOo 1′E2′ 2-10-4 Texas oOOOOOoo 2′E1′ 4-10-2 Southern Pacific, Overland ooOOOOOo F 0-12-0 Pennsylvania, Twelve-Wheel-Switcher OOOOOO 1′F 2-12-0 Centipede oOOOOOO 1′F1′ 2-12-2 Javanic oOOOOOOo 2′F1′ 4-12-2 Union Pacific ooOOOOOOo 2′G2′ 4-14-4 ooOOOOOOOoo nameless (AA) 0-2-2-0 O O B′B 0-4-4-0 nameless (Mallet) OO OO B′B1 0-4-4-2 nameless (Mallet) OO OOo 2′BB2′ 4-4-4-4 nameless (Pennsylvania Railroad Duplex) ooOO OOoo 3′BB3′ 6-4-4-6 oooOO OOooo 2′CB2′ 4-6-4-4 nameless (Pennsylvania Railroad Duplex) ooOOO OOoo C′C 0-6-6-0 Erie (Mallet) OOO OOO (1′C)C 2-6-6-0 nameless (Mallet) oOOO OOO (1′C)C1′ 2-6-6-2 Mallet Mogul (SP), Prairie Mallet (ATSF) oOOO OOOo (1′C)C2′ 2-6-6-4 nameless (Simple articulated) oOOO OOOoo (2′C)C2′ 4-6-6-4 Challenger (Simple articulated) ooOOO OOOoo (1′C)C3′ 2-6-6-6 Allegheny (Mallet/Simple articulated) oOOO OOOooo D′D 0-8-8-0 Angus (Mallet) OOOO OOOO (1′D)D 2-8-8-0 Bullmoose (Mallet) oOOOO OOOO (1′D)D1′ 2-8-8-2 Chesapeake, Mallet consolidation (Mallet) oOOOO OOOOo (1′D)D2′ 2-8-8-4 Yellowstone (Mallet/Simple articulated) oOOOO OOOOoo (2′D)D1′ 4-8-8-2 Cab Forward (Simple articulated) ooOOOO OOOOo (2′D)D2′ 4-8-8-4 Big Boy (Simple articulated) ooOOOO OOOOoo (1′E)E1′ 2-10-10-2 Virginian (Mallet) oOOOOO+OOOOOo (2′C1′)(1′C2′) 4-6-2+2-6-4 Double Pacific (Garratt) ooOOOo+oOOOoo (2′C2′)(2′C2′) 4-6-4+4-6-4 Double Hudson (Garratt) ooOOOoo+ooOOOoo (2′D)(D2′) 4-8-0+0-8-4 Double Mastodon (Garratt) ooOOOO+OOOOoo (2′D1′)(1′D2′) 4-8-2+2-8-4 Double Mountain (Garratt) ooOOOOo+oOOOOoo (2′D2′)(2′D2′) 4-8-4+4-8-4 Double Northern (Garratt) ooOOOOoo+ooOOOOoo
- ^ Colvin, Fred H. The railroad pocket-book: a quick reference cyclopedia of railroad information. New York, Derry-Collard; London, Locomotive Publishing Company (US-UK co-edition). 1906: L‑9.