机车轴式
不同机车轴式之對比

| 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. . New York, Derry-Collard; London, Locomotive Publishing Company (US-UK co-edition). 1906: L‑9.