Canadian National class S 2-8-2
Canadian National Railway Class S locomotives were a Class of wheel arrangement in the Whyte notation, or 1′D1′ in UIC classification. These locomotives were designed for 16° operating curvature. The first examples of this very successful class were built for the Grand Trunk Railway in 1913. Major purchases of the class continued through 1924. Sub-classes S-3 and S-4 employed higher pressure boilers with smaller diameter cylinders to achieve similar tractive effort with higher efficiency. The class remained in freight service until the final replacement of steam with diesel-electric locomotives. 53 were renumbered between 4045 and 4097 in 1956.
Sub-classes
Note - sub-class letters as assigned by Canadian National. CN received the GT engines after the CGR engines, thus the later-built engines received lower sub-class letters.| Sub-class | Builder | Works numbers | Dates | CN numbers | Notes |
| S-1-a | CLC | 1353–1402 | 1916–1917 | 3200–3249 | 50 built as CGR numbers 2800–2849 3239 preserved at the Canadian Railway Museum. Rest scrapped. |
| S-1-b | CLC | 1459–1508 | 1917–1918 | 3250–3299 | 50 built as CGR numbers 2850–2899. 3254 preserved in Steamtown. Rest scrapped |
| S-1-c | MLW | 58347–58376 | 1917 | 3300–3329 | 30 built as CGR numbers 2900–2929 |
| S-1-d | CLC | 1535–1594 | 1918–1919 | 3330–3389 | 60 built as CGR numbers 2930–2989. 3377 source parts for 3254. Rest scrapped |
| S-1-e | CLC | 1673–1687 | 1920–1921 | 3390–3404 | 15 built |
| S-1-f | ALCO | 52788–52812 | 1913 | 3405–3429 | 25 built as GT numbers 500–524 |
| S-1-f | BLW | 40210–40211 40255–40258 40269–40274 40339–40342 40365–40370 40379–40381 | 1913 | 3430–3454 | 25 built as GT numbers 525–549 |
| S-1-f | MLW | 53920–53969 | 1913 | 3455–3504 | 50 built as GT numbers 550–599 |
| S-1-g | CLC | 1449–1458 | 1917 | 3505–3514 | 10 built as GT numbers 485–494 |
| S-1-g | ALCO | 59950–59954 | 1918 | 3515–3519 | 5 built as GT numbers 480–484 |
| S-1-h | ALCO | 58315–58319 | 1918 | 3520–3524 | 5 built as GT numbers 495–499 |
| S-1-j | CN | 53928, 53954 | 1926 | 3198–3199 | 2 built |
| S-2-a | MLW | 64475–64509 | 1923 | 3525–3559 | 35 built. 3538 was wrecked in 1950 Canoe River train crash, remainder scrapped. |
| S-2-b | CLC | 1712–1721 | 1923 | 3560–3569 | 10 built |
| S-2-c | MLW | 65633–65662 | 1924 | 3570–3599 | 30 built |
| S-3-a | ALCO | 59563–59577 60300–60324 | 1918 | 3700–3739 | 40 USRA Light Mikados built as GT numbers 440–479. 3734 preserved. |
| S-3-b | ALCO | 64510–64517 | 1923 | 3740–3747 | 8 built |
| S-3-c | ALCO | 65317–65326 | 1924 | 3748–3757 | 10 built |
| S-4-a | CN | 1623 | 1930 | 3800 | 1 built |
| S-4-b | CLC | 1914–1918 | 1936 | 3801–3805 | 5 built |
The S-1-g/h classes were rebuilt by the GTW as 0-8-2 locomotives, making them capable transfer and switching engines while also hosting an improved ride quality due to the trailing truck. Their ride quality was so good that crews would come to nickname them "the Queen Mary". They also had their valve gear swapped, the "g" and "h" subclasses receiving Baker and Young valve gear respectively.