Steam locomotives operated in the United Kingdom with names beginning with I.
| Name | Railroad, # | Builder, s/n | Build date | Whyte type | Notes |
|---|---|---|---|---|---|
| Iago | GWR | 0-6-0ST | |||
| Ickenham Hall | GWR 5944 | 4-6-0 | |||
| Illustrious | LMS 5532 | 4-6-0 | |||
| Immingham | LNER 6097 | 4-6-0 | |||
| Impala | LNER 8303 | 4-6-0 | |||
| Implacable | LMS 5709 | 4-6-0 | |||
| Impregnable | LMS 5721 | 4-6-0 | |||
| Inchcape | GWR 3430 | 4-4-0 | |||
| India | LMS 5574 | 4-6-0 | |||
| Indomitable | LMS 5720 | 4-6-0 | |||
| Indore | LMS 5592 | 4-6-0 | |||
| Industry | B&GR | 2-4-0 | |||
| Inflexible | LMS 5727 | 4-6-0 | |||
| Inkermann (1st) | GWR | 4-2-2 | |||
| Inkermann (2nd) | GWR | 4-2-2 | |||
| Inverness-shire | LNER 329 | 4-4-0 | |||
| Invincible | LMS 5715 | 4-6-0 | |||
| Iris | GWR | 0-6-0 | |||
| Irish Free State | LMS 5572 | 4-6-0 | |||
| Irish Guardsman | LMS 6116 | 4-6-0 | |||
| Iron Duke | 4-2-2 | Operable replica of GWR's first Iron Duke locomotive. | |||
| Iron Duke | BR 70014 | Crewe | 6/1951 | 4-6-2 | Wd 12/1967; scr 4/1968. |
| Iron Duke (1st) | GWR | 4-2-2 | |||
| Iron Duke (2nd) | GWR | 4-2-2 | |||
| Ironside | SR 3458 | 0-4-0ST | |||
| Irresistible | LMS 5710 | 4-6-0 | |||
| Isambard Kingdom Brunel | GWR 5069 | 4-6-0 | |||
| Iseult | BR 73116 | Doncaster | 11/1956 | 4-6-0 | Wd 11/1964; scr 2/1965 at Eastleigh. |
| Iseult | SR 749 | 4-6-0 | |||
| Isinglass | LNER 2562 | 4-6-2 | |||
| Isle of Jersey | GWR 3284 | 4-4-0 | |||
| Isle of Man | LMS 5511 | 4-6-0 | |||
| Ivanhoe | GWR | 4-4-0 | |||
| Ivanhoe | GWR 2980 | 4-6-0 | |||
| Ivanhoe | LNER 9339 | 4-4-0 | |||
| Ixion | GWR | 2-2-2 | |||
| Ixion | SDR | 4-4-0ST |