A relatively small batch of tall-drivered Pacifics built over an 8-year period by the Canadian Pacific and the Montreal Locomotive Works.
The boiler had a coned second course and the steam dome on the first course. As delivered, the class was fitted with the 22-element Vaughan-Horsey superheater, which is very similar in basic design to the much-better-known Schmidt smoke-tube design. The data in the specifications reflect that installation.
At a later date, the CPR replaced the Vaughan-Horsey superheater with the more widely used Schmidt Type A in many of its early Pacifics. Locobase 4518, although it describes the G2a, has data exactly the same as the G1 after the change.
Locobase divides this class into several variants depending on the superheater and the cylinder volume. In the present entry, the class refers to the version using the Vaughan-Horsey superheater that was orginally installed when these engines were delivered in 1906-1907. They had 11" (279 mm) piston valves. Arch tubes added 16 sq ft to the firebox heating surface.
The principal difference between the Vaughan-Horsey and the Schmidt or Cole smoke-tube superheater was that the Vaughan-Horsey's superheater tubes were connected "separately and individually to the headers", as Vaughan put in his report to the 40th Annual Convention of the American Railway Master Mechanics' Association in 1906. (See pp. 286-287 for his comments on initial problems with the design.)
In later days, the tubes were shortened by 6" and most G2s had only 189 2" (15156) or 175 2 1/4" boiler tubes. (See Locobases 15156 and 10809, respectively.
For the Schmidt Type A variant, see Locobase 4518. Firebox heating surface for both versions included 24 sq ft of arch tubes.
Similar in most respects to the G1s of the same span (1906-1914), this much larger class had 70" drivers. They were supplied by Alco-Schenectady, Canadian Pacific shops, and Montreal Loco Works.
They stayed in service until 1940-1961.
Locobase 6556 for the original 1906 Vaughan-Horsey version of this Pacific.
As the G2's service career wore on, many of the locomotives were altered in one way or another. This entry shows the later version of the Vaughan & Horsey subtype fitted with larger-diameter tubes and pistons, but still using the 5" diameter flues. Firebox heating surface included 24 sq ft of arch tubes.
Locobase 6556 for the original 1906 Vaughan-Horsey version of this Pacific.
As the G2's service career wore on, many of the locomotives were altered in one way or another. This entry shows the later version of the Vaughan & Horsey subtype fitted with fewer tubes, larger-diameter flues, and more cylinder volume. Firebox heating surface included 24 sq ft (2.2 sq m) of arch tubes.
Locobase divides this class into two variants depending on the superheater that was added to the design some time after they were put in service in 1906-1914. This entry applies to those upgraded with the Schmidt Type A superheater. Unlike the upgraded Ten-wheelers, most Schmidt engines retained their 200-psi setting. Firebox heating surface for both versions included 24 sq ft of arch tubes.
Almost all of the conversions used the 30-flue Type A installation shown in the specs. Two were fitted with a 28-tube Type A with 5 1/2" flues and 147 2 1/4" tubes.
Other sub-classes (likely a few in each) offered combinations such as 21 1/4"-diameter pistons and 225-psi boiler, 20"-diameter pistons and a 250-psi boiler, and in some cases, retention of the original 21"-diameter piston and 200-psi boiler. By the diagram book's 1947 publication date, all G2s then in service had been converted to the Schmidt superheater variant. A few had been fitted with Elesco feed water heaters.
For the Vaughan-Horsey variant, see Locobase 6556.
Similar in most respects to the G1s of the same span (1906-1914), this much larger class had 70" drivers. They were supplied by Alco-Schenectady, Canadian Pacific shops, and Montreal Loco Works and stayed in service until 1940-1961.
First in a series of big, powerful Pacifics. The figure for number of engines in the class covers all versions of the G3. Winterrowd spells out all of the considerations behind this design in his Railway Review article.
A National Park Service Steamtown special history study on its G3c gives details on how these came to be produced:"William H. Winterrowd had become chief mechanical officer of the Canadian Pacific Railway (CPR) in April 1918 as the World War was winding down." The study describes the other types of locomotives Winterrowd developed, then notes:
"For passenger service, CPR needed heavier locomotives because "heavyweight" six-wheel truck all-steel cars had rapidly replaced the older, lighter wooden passenger cars on main line runs. Building on Vaughan's successful G-l and G-2 Pacifics manufactured well before the World War, Winterrowd's team produced plans for four G-3-a 4-6-2s with 75-inch drive wheels for service over relatively flat terrain and five G-4-a Pacifics with smaller 70-inch drivers [Locobase 4522] for main line service in hilly terrain. Numbered 2300 through 2303, one of the G-3-a locomotives appeared in July 1919 and the other three in August."
The firebox had a short combustion chamber and five arch tubes contributing to direct heating surface area. Fourteen-inch (356 mm) piston valves enjoyed 7" (179 mm) travel
After evaluating the relative performance of the two classes, Winterrowd concluded that the 75" driver was the appropriate size for the heavyweight expresses he wanted to pull. So a year later, CP's shops turned out five G-3b in August-September 1920 and another in January 1921. A year and a half later, the class went into series production with class G3c 2310-2318 appearing in June 1923 and 2320-2325 in July.
These all had Type A superheaters and Elesco feed water heaters. They would later trail larger tenders weighing 295,000 lb (133,810 kg) loaded with 14,400 US gallons (54,504 litres) of water and 21 long tons (23.2 short tons) of coal.
The G3d with nickel-steel boiler appears in Locobase 133, while later G3s with Type E superheaters are described in Locobases 5049 and 134."
Also had 28 2" tubes. G-3d firebox had combustion chamber and five arch tubes . A nickel-steel boiler allowed considerably higher boiler pressure (which led to a reduction in cylinder volume) and a reduction in the number of fire tubes. On balance, there was less total heating surface, but more of it was superheated.
3e, f, g, & h were later series with much more superheat surface; see Locobases 5049 and 134."
These were the first of the "superpower" G3s with smaller cylinder diameter, higher BP, and a Type E superheater that resulted in a much higher percentage of dry steam. The firebox had 33 sq ft of thermic syphons.
G3e 2351-2365 works #1944-1958 October-November 1938
G3f 2366-2377 1970-1981 April-June 1940
Data taken from specifications published by CLC in 1945 and reproduced in http://www.trainweb.org/oldtimetrains/altloco.html (consulted in May 2002). The table depicts the G3e, as indicated by a reference to a 1938 order; G3fs were identical except for slightly higher weights.. A later sub-class is described on Locobase 134.
Last G3 variant and the design that was produced in the greatest numbers. A shorter, obviously less crowded boiler had 14 fewer small tubes and 27 flues that were 1/2" (12.7 mm) larger in diameter.
G3g 2378- 2417 CLC works #1982-2021 January 1942 - February 1943
G3h 2418-2462 CLC 2126-2170 August 1944 - April 1945
G3j 2463-3427 MLW 76116-76125 June 1948
This design pulled not only passenger, but also freight trains.
These were the only G4s because WH Winterrowd, Chief Mechanical Engineer, compared their utility to the identical G3 class shown in Locobase 2738 and found that the latter's 75" were more to his liking. So production of this 70" variant stopped at 18.
Firebox heating surface included 40 sq ft (3.7 sq m) of arch tubes and a short combustion chamber. Fourteen-inch (356 mm) piston valves served the cylinders.
The class could trail one of two tenders, either the 12,000 Imperial gallon/21 ton coal version or, for those G4s operating as oil burners, 8,000 ImpGal (36,336 litres) of water and 3,000 ImpGal (13,626 litres) of oil. According to Chris Hohl, the coal burners were 2708, 2710-2715 and the oil burners were road numbers 2700-2707, 2709, 2716-2717. 2711 was tested with smoke deflectors in 1941.
This satisfactory design carried on until 1954-1965."
"They proved as fast and as efficient as they were handsome," says OS Nock (RWC VI, pl 33), " and 'saw steam out' on many secondary lines of the CPR."
A February 1954 article in Trains magazine by FH Howard, reproduced on http://www.trainweb.org/oldtimetrains/destinedtodie.html (consulted in May 2002), agreed and provided many details on the class. Howard noted that the 1944 design had "scores of improvements", most notably a front-end throttle, roller bearings on the leading engine truck, and a Signal Foam Meter. Housing the throttle in the front allowed use of a dry pipe with slots along the underside, an arrangement "used", according to Howard, "for some years on this railroad instead of a steam dome".
Under the firebox was "probably the simplest trailing truck ever devised: not a truck at all, but an axle carried in the rigid frame with overwide pedestals set at a backward angle so when the axle moved laterally on curves, the journals were displaced longitudinally, giving truck action"
After successful trials in the East (1201) and West (1200), Montreal Locomotive Works delivered 30 G-5bs with mechanical stokers and Elesco exhaust steam injectors. 1946 saw 20 more from MLW and 20 from CLC and 1948 closed out the class with 30 from Canadian Loco.
(See Locobase 2413 for the very similar New South Wales C38. The two classes were designed separately for two very different railways, yet they have a striking resemblance)
|Specifications by Steve Llanso|
|Class||G1||G2 - Vaughan-Horsey - 1st mod||G2d - Vaughan-Horsey||G2f - Vaughan-Horsey||G2p-u Type A - 30 unit||G3a/G3b/G3c||G3d||G3e/G3f||G3g/G3h/G3j||G4a/G4b||G5|
|Railroad||Canadian Pacific||Canadian Pacific||Canadian Pacific||Canadian Pacific||Canadian Pacific||Canadian Pacific||Canadian Pacific||Canadian Pacific||Canadian Pacific||Canadian Pacific||Canadian Pacific|
|Builder||several||several||several||several||several||Angus Works||Montreal LW||Canadian Locomotive Co||several||Canadian Pacific||Several|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.39||0.39||0.39||0.39||0.39||0.38||0.38||0.38||0.38||0.38||0.39|
|Overall Wheelbase (engine & tender)||59.27'||59.96'||64.54'||64.54'||64.54'||67.83'||73.81'||75.62'||67.09'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||139000 lbs||139300 lbs||155000 lbs||155000 lbs||155000 lbs||181500 lbs||183900 lbs||198000 lbs||199600 lbs||193000 lbs||151000 lbs|
|Engine Weight||212000 lbs||214300 lbs||237000 lbs||237000 lbs||237000 lbs||299000 lbs||306500 lbs||321000 lbs||323000 lbs||318000 lbs||229500 lbs|
|Tender Light Weight||122700 lbs||122700 lbs||142000 lbs||169000 lbs||169000 lbs||178000 lbs||238000 lbs||222000 lbs||196760 lbs||295000 lbs||191000 lbs|
|Total Engine and Tender Weight||334700 lbs||337000 lbs||379000 lbs||406000 lbs||406000 lbs||477000 lbs||544500 lbs||543000 lbs||519760 lbs||613000 lbs||420500 lbs|
|Tender Water Capacity||5000 gals||5000 gals||5000 gals||7000 gals||8400 gals||9600 gals||9500 gals||12000 gals||12000 gals||14388 gals||9600 gals|
|Tender Fuel Capacity (oil/coal)||10 tons||10 tons||12 tons||12 tons||12 tons||12 tons||12 tons||18 tons||18 tons||21 tons||14 tons|
|Minimum weight of rail (calculated) on which locomotive could run||77 lb/yard||77 lb/yard||86 lb/yard||86 lb/yard||86 lb/yard||101 lb/yard||102 lb/yard||110 lb/yard||111 lb/yard||107 lb/yard||84 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||200 psi||200 psi||200 psi||200 psi||200 psi||200 psi||250 psi||275 psi||275 psi||205 psi||250 psi|
|Cylinders (dia x stroke)||21" x 28"||21" x 28"||21" x 28"||22.25" x 28"||22.5" x 28"||25" x 30"||23" x 30"||22" x 30"||22" x 30"||24.5" x 30"||20" x 28"|
|Tractive Effort||27989 lbs||29988 lbs||29988 lbs||33664 lbs||34425 lbs||42500 lbs||44965 lbs||45254 lbs||45254 lbs||44826 lbs||34000 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.97||4.65||5.17||4.60||4.50||4.27||4.09||4.38||4.41||4.31||4.44|
|Firebox Area||180 sq. ft||191 sq. ft||199 sq. ft||199 sq. ft||199 sq. ft||297.60 sq. ft||291 sq. ft||291 sq. ft||291 sq. ft||298 sq. ft||199 sq. ft|
|Grate Area||45.60 sq. ft||48 sq. ft||45.60 sq. ft||45.60 sq. ft||45.60 sq. ft||65 sq. ft||65 sq. ft||65 sq. ft||65 sq. ft||65 sq. ft||45.60 sq. ft|
|Evaporative Heating Surface||2957 sq. ft||3122 sq. ft||2914 sq. ft||2926 sq. ft||2610 sq. ft||3530 sq. ft||3272 sq. ft||3497 sq. ft||3176 sq. ft||3530 sq. ft||2576 sq. ft|
|Superheating Surface||528 sq. ft||530 sq. ft||433 sq. ft||433 sq. ft||675 sq. ft||803 sq. ft||864 sq. ft||1473 sq. ft||1475 sq. ft||803 sq. ft||744 sq. ft|
|Combined Heating Surface||3485 sq. ft||3652 sq. ft||3347 sq. ft||3359 sq. ft||3285 sq. ft||4333 sq. ft||4136 sq. ft||4970 sq. ft||4651 sq. ft||4333 sq. ft||3320 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||263.44||278.14||259.61||232.21||202.55||207.11||226.81||264.94||240.62||215.65||253.02|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||9120||9600||9120||9120||9120||13000||16250||17875||17875||13325||11400|
|Same as above plus superheater percentage||10488||11040||10306||10306||11035||15470||19663||23238||23595||15857||13908|
|Same as above but substitute firebox area for grate area||41400||43930||44974||44974||48158||70829||88028||104033||105633||72697||60695|