Class U-1-a (Locobase 7102)

Data from CV 1957 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

These Mountains were owned by the CV's parent Canadian National Railway and leased to the Vermont railroad. The firebox heating surface included a combustion chamber, 14 sq ft in 2 arch tubes, and 76 sq ft in Nicholson thermic syphons. They also mounted Coffin feedwater heaters. Relatively small and light as North American 4-8-2s went, the U-1s were charged with moving The Montrealer over the CV's portion of the New York-Montreal express. Drury (1993) comments that they "were about the same size as the Florida East Coast 400 series ..." (See Locobase 1348). Indeed, a comparison of the specs shows them to have been virtually identical in every respect except for the CV engines having a higher boiler pressure.

Retirements came only in the late 1950s.

Class U-1-f (Locobase 197)

Last in a series of U-1 4-8-2s. The earlier series were:

U-1a 16 Canadian Loco 1923 6000-6015 (Locobase 7333)

U-1b 21 same 1924 6016-6036 (Locobase 7333, Locobase 7334)

U-1c 5 Baldwin 1925 6037-6041 (had 26-in diameter pistons, 210-lb BP, 9,600-lb TE, combustion chamber 36 1/2 in long, 22.75 between tube sheets.)

U-1d 5 Canadian 1929 6042-6046

U-1e 12 Montreal 1930 6047-6058

The U-1fs were updates of this design delivered 14 years later. The biggest improvement was the cast steel frame; almost as useful was the exhaust steam injector. The boiler layout took on a Superpower look as well, with the small tubes reduced to a handful and the larger flues dominating the vessel. The website for the 6060, a restored U-1-f -- http://www.6060.org/6060development.htm, accessed 16 September 2007 -- gives a detailed description of the development considerations for this class:

"Dimensionally similar,the U-1-f class was a far cry from the U-1-a in mechanical and cosmetic details. The new locomotives were built on and around a one piece cast frame, made by General Steel Castings, which included the pilot, cylinder and valve block and hefty mounting brackets for the air compressor and exhaust steam injector ...

"Considerable design work had gone into the 'internal' streamlining of the 6060's. Tests, experiments and the experience of other railways had proven conclusively that if the steam flow from boiler to cylinders to smokestack was along a smooth and gently curved and totally unrestricted passage, then the engineer could anticipate reduced back pressure, swifter throttle response and reduced fuel consumption."

There was more innovation, according to the account. To reduce stress on the rail and on the frame, the class used a "complex" suspension setup that virtually eliminated nosing and allowed reduced counterbalancing. Although equipped with relatively small 73" drivers, which incidentally suited the class well for fast-freight duties, the engines were able hit very high speeds as passenger haulers. One account gives a 125-mph top speed, although one suspects that wasn't officially timed.

The engine was colorfully trimmed and graceful in appearance, with a blunted cap covering the smokebox door. This feature inspired the nickname "Bullet-Nosed Betty".

Class U-1a/U-1b - Robinson (Locobase 7333)

Data from CN to 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

The CLC supplied 37 Mountains to the CN in two years. A majority was fitted with the Robinson superheater while the others, shown in Locobase 7334, had Schmidt Type A superheaters. The Robinson engines showed in this entry had works #1696-1711 (1923) and 1764-1769 (1924).

All had the 14" piston valves that would be standard on these 4-8-2s, but unlike later sub-classes, U-1a and U-1b engines did not have thermic syphons. A later CN diagram says that the Robinson superheaters were replaced by the Schmidt design - the diagram's superheater surface area difference was not changed, however.

Class U-1b - Schmidt (Locobase 7334)

Data from CN to 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

The CLC supplied 37 Mountains to the CN in two years. A majority was fitted with the Robinson superheater; these are shown in Locobase 7333. This clutch of 15 supplied by the CLC in 1924 (works #1744-1758) had Schmidt Type A superheaters that added more surface area.

All had the 14" piston valves that would be standard on these 4-8-2s, but unlike later sub-classes, U-1a and U-1b engines did not have thermic syphons. One oddity in the diagrams is that the firebox is shown with the 4-ft-long combustion chamber, but the longer tubes and flues

Class U-1c (Locobase 5303)

Firebox had arch tubes.

Steamtown's Special History Study of 6039 -- http://www.cr.nps.gov/history/online_books/steamtown/shs2h.htm (visited 4 Jan 2003) is the source for the data. Much of boiler information comes from the reproduced original specification card, which also contains test strengths, thread pitches for the staybolts and all the other information that validates the boiler as being properly constructed.

Steamtown's history notes that these engines were delivered with feedwater heaters, power reverse gear, and automatic or mechanical stokers. They were the first GTW locomotives to offer both the all-weather cab and the Vanderbilt tender. They were also Grand Trunk's only Mountains; the railroad soon added a trailing axle to the design, creating some relatively light 4-8-4s.

Originally put in service on heavy passenger runs, the U-1c proved equally capable of hauling fast freights.

In the 30s, the friction bearings on all engine and tender axles were replaced by roller bearings. Later most were refitted with vanadium steel frames and Boxpok drivers.

Class U-1d/e (Locobase 7332)

Data from CN to 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

These followed the U-1c (Locobase 5030) by 3 years and came from different builder. Canadian Locomotive Works delivered the first five (works #1853-1857) in 1929; these had Walschaert valve gear. Montreal Locomotive Works followed in 1929-1930 with 12 more (works #68343-68354) fitted with Baker gear.

Although the grate was essentially the same, tubes and flues were 7" shorter and the combustion chamber was a foot longer. The firebox also had thermic syphons. As with all the 4-8-2s in this series, piston valves measured 14" in diameter.

Some were oil-fired (4,000-gal tender capacity) and most had smoke deflectors (6047-6049, 6051-6056).