| Canadian National U-1-a and U-1-b | |
| Powertype: | Steam |
| Builder: | Canadian Locomotive Company |
| Builddate: | 1923–1924 |
| Totalproduction: | 16 (U-1-a) 21 (U-1-b) |
| Rebuilddate: | 1947 (1) |
| Numberrebuilt: | 1 ( 6001) |
| Whytetype: | 4-8-2 |
| Uicclass: | 2′D1′ h2 |
| Leadingdiameter: | NaN3NaN3 |
| Driverdiameter: | 733NaN3 |
| Trailingdiameter: | 433NaN3 |
| Minimumcurve: | 16° |
| Wheelbase: | Loco: 41feet |
| Length: | 90feet |
| Width: | 10feet |
| Weightondrivers: | 233790- |
| Locoweight: | 355570- |
| Locotenderweight: | 602600- |
| Fueltype: | Coal or oil |
| Watercap: | 9500impgal10000impgal |
| Boilerpressure: | 210lbf/in2 |
| Firearea: | 66.7square feet |
| Tubesandflues: | 3730square feet |
| Fireboxarea: | 319square feet |
| Totalsurface: | 4049square feet |
| Superheatertype: | Schmidt |
| Superheaterarea: | 810- |
| Cylindercount: | Two, outside |
| Cylindersize: | 26x |
| Valvegear: | Walschaerts |
| Tractiveeffort: | 49590lbf |
| Factorofadhesion: | 4.71 – 4.74 |
| Trainheating: | Steam heat |
| Locobrakes: | Independent air |
| Trainbrakes: | Automatic air |
| Operator: | Canadian National Railways |
| Powerclass: | 50% |
| Numinclass: | 16 (U-1-a) 21 (U-1-b) |
| Fleetnumbers: | 6000–6015 (U-1-a) 6016-6036 (U-1-b) |
| Retiredate: | 1950 (6004) 1951-1962 |
| Preservedunits: | 6015 |
| Disposition: | 6015 preserved remainder scrapped |
| Notes: | References for above:[1] |
[2] The Canadian National U-1-a U-1-b class locomotives were three subclasses of 37 4-8-2 Mountain-type steam locomotives built for the Canadian National Railways between 1923 and 1924. They were retired between 1951 and 1962 .
| Year | Subclass | Quantity | Manufacturer ! | Serial nos. | CN Nos. | Notes | |
|---|---|---|---|---|---|---|---|
| 1923 | U-1-a | 16 | 1696–1711 | 6000–6015 | 6015 preserved in Jasper, Alberta, since 1972 | ||
| 1924 | U-1-b | 21 | 1744–1758, 1764–1769 | 6016–6036 | All scrapped | ||
On 1 September 1947, locomotive 6001 was involved in the Dugald rail accident. It collided with another CN 4-8-2 numbered 6046. 6001 was later rebuilt by CN.
On 21 November 1950, locomotive 6004 was severely damaged a head-on collision with S-2-a 2-8-2 3538 at Canoe River, British Columbia. It was scrapped in June 1951 (as was the 3538). There was a gap of four years before the next U-1-a or U-1-b went: two were scrapped in 1955, four in 1957, six in 1958, six in 1959, eight in 1960, seven in 1961, and the last two, 6000 and 6001 in 1962.[3]
U-1-a 6004 is the subject of a 1924 publicity poster by C. Norwich. It depicts the locomotive speeding along in the foreground, while in the background is a pine-covered, snow-capped mountain peak. Across the top is the "Canadian National Railways" logotype; across the bottom are the words, "Across Canada", and in the lower left, above the artist name and date is "The Continental Limited in the Canadian Rockies"[4]
One locomotive has been preserved:
