Alabama & Vicksburg / Illinois Central / Vicksburg, Shreveport & Pacific 4-6-2 "Pacific" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 1000 (2) (Locobase 9386)

Data from IC 1913ca Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

As described in Locobase 5327, this engine was originally procured from Rogers as a Prairie in 1901 to test against an Atlantic (4-4-2) design. The

Sometime later, it was again rebuilt with 24" x 26" cylinders; see Locobase 7047.


Class 1000 (2) - superheated (Locobase 7047)

Data from IC 1930 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

After the original conversion from Prairie to Pacific shown in Locobase 9386, the IC later enlarged the basic design to take bigger cylinders, and added a superheater and 22 sq ft of arch tubes to the firebox. The result was a locomotive with almost the same amount of heating surface, but using drier steam admitted through 14" (356 mm) piston valves.


Class 1031 / 1054 (Locobase 6946)

Data from 1928 Illinois Central locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Schenectady supplied five in November 1905 (works numbers 29542-29546), five in October 1906 (40355-40359), and eight in September 1907 (43463-43470). Brooks followed with fifteen in 1910 (49176-49190) that weighed a ton less each.

This series of small batches represented the IC's first Pacifics.They arrived as saturated-steam locomotives pressed to about as high a boiler pressure as was deemed feasible. The cylinder diameter, which seems small, was in fact among the greatest for the early orders of 4-6-2s.

On the heels of the last of these "wet" Pacifics came the first of those built from scratch with superheaters. See Locobase 6947. This earlier group was later converted to the same boiler standard as those that were delivered with superheaters. Measurement quirks probably account for the slight discrepancies in heating surface measurements.


Class 1049 (Locobase 9388)

Data from 1928 Illinois Central locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also Locobase, Volume 33, p. 113. (Thanks to Chris Hohl for his 9 May 2015 email noting an error in the cylinder diameter.) Works numbers were 33774-33775, 33813-33814, and 33824 in September 1909.

Five "Harriman Common Standard" Pacifics according to Drury (1993). They were delivered by Baldwin in three small batches in 1909;. Firebox heating surface included 28 sq ft of arch tubes and steam admission came through 12"(305 mm) diameter piston valves. A note in the Baldwin specs reports that as National Tube Company didn't make charcoal iron flues, they would be manufactured by Worth Tube Company. The front 4-wheeled truck was a swing-motion design that allowed 4" (102 mm) swing to either side; the rear two-wheel truck was a Rushton Radial.

The superheated update is found on Locobase 1355.


Class 1049 - superheated (Locobase 1355)

Data from 1928 Illinois Central locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl's 5 April 2015 email reporting the tender's fuel and water capacity.)

Five "Harriman Common Standard" Pacifics according to Drury (1993). They were delivered by Baldwin in three small batches in 1909; works numbers were 33774-33775, 33813-33814, and 33824. Firebox heating surface included 28 sq ft of arch tubes and steam admission came through 14"-diameter piston valves.


Class 1069 (Locobase 6947)

Data from 1913ca and IC 9 - 1928 Illinois Central locomotive diagram books supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also data for 1138 from reproduction of 1913 Alco Bulletin 1016 on Richard Leonard's http://www.railarchive.net/alcopacifics/index.html (accessed 16 June 2006). Works numbers were Brooks: 50095-50099 in July 1911, 50419-50428 in August, 50834-50843 in January 1912, 52143-52162 in October; followed by Richmond works numbers 53196-53199 in February 19813, 53200-53220 in March.

As soon as the Schmidt superheater began appearing in some American locomotives, it began appearing almost everywhere. In the case of the IC's Pacifics, the railroad had just added fifteen saturated-steam engines to its growing stud of 4-6-2s when it ordered a quartet (builder's numbers 50095-50099) that repeated most of the specifications of the 1054s (Locobase 6946), but rearranged the boiler to house a moderately sized superheater installation. Firebox heating surface included 28.1 sq ft (2.6 sq m) of arch tubes. The new engines also featured a significant increase in cylinder volume from enlarging their diameters to 25"; 14" (356 mm) piston valves now supplied those cylinders.

Apparently pleased with the result, the IC ordered 65 more over the next two years.


Class 1139 (Locobase 3304)

One of the locomotives to which James Partington, Estimating Engineer for Alco, compared his company's #50000 in "Avoidable Waste in Locomotive Operation as Affected by Design", Railway Age, Volume 95, No. 11 (5 November 1921), pp. 673-677. Annoyingly, he chose not to identify any of these rivals.

Locobase had been carrying this locomotive as "unknown". According to Partington, one of his comparison locomotives had 79" drivers and 26" x 28" cylinders. After review of the IC 9 - 1928 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange, Locobase believes that the class shown above is such a close match that it must be the one to which Partington referred, except for the driver diameter. In addition to the cylinder dimensions and boiler pressure, the grate area and weights match exactly while the heating surface areas were within a few sq ft.

This big class followed an even larger class of Pacifics of somewhat smaller dimensions; see Locobase 6947.

The first batch of 40 came from Brooks in 1916 and 1918; their builder's numbers were 56083-56102 (1916) and 58185-58204 (1918). These had 235 boiler tubes which resulted in about 20 sq ft more heating surface than the Schenectady engines that followed in 1920. Schenectady's builder's numbers were 62516-62540 and they had the areas and tube count shown in the specs.


Class B (Locobase 6085)

Data from the 1926 Alabama & Vicksburg locomotive diagram book supplied in March 2004 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 68, pp. 86+. (Thanks to Chris Hohl for his 24 April 2015 email and spreadsheet spelling out the specs for the A&V engines.) Works numbers were 57639, 57655-57656 in February 1924.

These were the largest engines procured by the A & V, bigger even than the 2-10-2s they'd bought a few years earlier. Their frames were to be made "extra heavy to withstand severe service and to guard against breakage." Baldwin's estimate for adhesion weight was 164,000 lb and for engine weight 282,000 lb; as the specs show, these figures were very close to operational weights.

Firebox heating surface included 62 sq ft (5.75 sq m) of Nicholson syphons and steam was delivered through 14" (356 mm) diameter piston valves. The valve gear in use on this class was the rare Young gear; see Locobase 6082 for a description of the gear.

When the IC took control of the Vicksburg Route, this class was renumbered 1310-1312.


Class B (Locobase 6084)

Data from the 1926 Alabama & Vicksburg locomotive diagram book supplied in March 2004 by Allen Stanley from his extensive Rail Data Exchange. See also IC 1955 Locomotive Diagrams and DeGolyer, Volume 59, pp. 81+ and Volume 68, pp. 76+. (Thanks to Chris Hohl for his 24 April 2015 email and spreadsheet spelling out the specs for the A&V engines.) Works numbers were 51199, 51259 in February 1919 and 55416 in May 1922.

The Vicksburg, Shreverport & Pacific Pacifics were confined to these three, the third of which was originally delivered to the Alabama & Vicksburg as their 480. The only signficant difference between it and the other two was the choice of Young valve gear. Very similar to the 1914 NO & NE locomotives (see Locobase 6090), these had the same superheater area and 13" (330 mm) diameter piston valves, but a larger firebox fitted with the patented Gaines combustion chamber. Their operating environment wasn't taxing, offering 1% grades and 6 degree curves. Rail weight ran to 75 lb/yard (37.5 kg/metre).

When taken up by the Illinois Central, they were renumbered three times, ending with 1000-1002. In 1943, all three were substantially rebuilt with results that are implausible at best. The IC diagram shows an engine with 26" x 28" (660 x 711 mm) cylinders, 58 sq ft (5.4 sq m) of thermic syphons, and 220 psi of boiler pressure. Tractive effort soared to 52,052 lb (23,610 kg). Locobase suspects these numbers were incorrectly brought over from another, larger design because the factor of adhesion derived from this new tractive effort and the same weight on the drivers is an impossible 2.7. Locobase suspects that all that changed in this trio was the adoption of thermic syphons and the deletion of the arch tubes and ten small tubes from the boiler.

1001 was scrapped first in March 1954; 1000 and 1002 followed 14 months later in May 1955.

Specifications by Steve Llanso of Sweat House Media
Class1000 (2)1000 (2) - superheated1031 / 105410491049 - superheated
Locobase ID9386 7047 6946 9388 1355
RailroadIllinois Central (IC)Illinois Central (IC)Illinois Central (IC)Illinois Central (IC)Illinois Central (IC)
CountryUSAUSAUSAUSAUSA
Whyte4-6-24-6-24-6-24-6-24-6-2
Number in Class113355
Road Numbers100010001031-1048, 1054-10681049-10531049-1053
GaugeStdStdStdStdStd
Number Built335
BuilderICICAlcoBaldwinIC
Year19071920190519091920
Valve GearBakerBakerWalschaertBakerBaker
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.33 / 4.0613.33 / 4.0613 / 3.9613.33 / 4.0613.33 / 4.06
Engine Wheelbase (ft / m)32.83 / 10.0133.83 / 10.3133.83 / 10.3133.33 / 10.1633.33 / 10.16
Ratio of driving wheelbase to overall engine wheebase 0.41 0.39 0.38 0.40 0.40
Overall Wheelbase (engine & tender) (ft / m)63.62 / 19.3945.12 / 13.7565.12 / 19.8564.10 / 19.5464.10 / 19.54
Axle Loading (Maximum Weight per Axle) (lbs / kg)48,00054,000 / 24,494
Weight on Drivers (lbs / kg)144,250 / 65,431147,970 / 67,118147,600 / 66,950141,000 / 63,957151,850 / 68,878
Engine Weight (lbs / kg)215,500 / 97,749231,070 / 104,812224,000 / 101,605222,000 / 100,698242,150 / 109,838
Tender Loaded Weight (lbs / kg)164,000 / 74,389179,400 / 81,375161,240 / 73,137161,240 / 73,137161,240 / 73,137
Total Engine and Tender Weight (lbs / kg)379,500 / 172,138410,470 / 186,187385,240 / 174,742383,240 / 173,835403,390 / 182,975
Tender Water Capacity (gals / ML)9000 / 34.099000 / 34.099000 / 34.099000 / 34.099000 / 34.09
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)15 / 13.6015 / 13.6015 / 13.6010 / 9.1010 / 9.10
Minimum weight of rail (calculated) (lb/yd)8082827884
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)75 / 190575 / 190575 / 190577 / 195677.50 / 1969
Boiler Pressure (psi / kPa)200 / 13.80180 / 12.40210 / 12.40200 / 13.80180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)20" x 28" / 508x71124" x 26" / 610x66022.5" x 26" / 572x66022" x 28" / 572x71124" x 28" / 610x711
Tractive Effort (lbs / kg)25,387 / 11515.3630,551 / 13857.7231,327 / 14209.7129,920 / 13571.5031,840 / 14442.40
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.68 4.84 4.71 4.71 4.77
Heating Ability
Firebox Area (sq ft / m2)201 / 18.68223.40 / 20.76186.50 / 17.33174 / 16.17146 / 13.56
Grate Area (sq ft / m2)51 / 4.7450.60 / 4.7051 / 4.7449.50 / 4.6049.50 / 4.60
Evaporative Heating Surface (sq ft / m2)3709 / 344.702967 / 275.743332 / 309.553048 / 283.272853 / 265.05
Superheating Surface (sq ft / m2)658 / 61.15626 / 58.16
Combined Heating Surface (sq ft / m2)3709 / 344.703625 / 336.893332 / 309.553048 / 283.273479 / 323.21
Evaporative Heating Surface/Cylinder Volume364.30217.94278.48247.42194.60
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,200910810,71099008910
Same as above plus superheater percentage10,20010,74710,710990010,514
Same as above but substitute firebox area for grate area40,20047,45039,16534,80031,010
Power L111,57516,5389356816314,617
Power MT530.71739.20419.24382.90636.65

Specifications by Steve Llanso of Sweat House Media
Class10691139BB
Locobase ID6947 3304 6085 6084
RailroadIllinois Central (IC)Illinois Central (IC)Alabama & Vicksburg (IC)Vicksburg, Shreveport & Pacific (IC)
CountryUSAUSAUSAUSA
Whyte4-6-24-6-24-6-24-6-2
Number in Class706533
Road Numbers1069-11381139-1203480-482 / 1310-1312380-382
GaugeStdStdStdStd
Number Built706533
BuilderAlcoAlcoBaldwinBaldwin
Year1911191619241919
Valve GearWalschaertWalschaertYoungWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13 / 3.9613 / 3.9613 / 3.9612 / 3.66
Engine Wheelbase (ft / m)33.83 / 10.3134.33 / 10.4636.08 / 1132.92 / 10.03
Ratio of driving wheelbase to overall engine wheebase 0.38 0.38 0.36 0.36
Overall Wheelbase (engine & tender) (ft / m)63.33 / 19.3067.04 / 20.4370.77 / 21.5767.42 / 20.55
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)150,500 / 68,266169,500 / 76,884163,480 / 74,153141,000 / 63,957
Engine Weight (lbs / kg)245,000 / 111,130280,000 / 127,006279,780 / 126,906217,500 / 98,656
Tender Loaded Weight (lbs / kg)176,000 / 79,832182,200 / 82,645166,000 / 75,296160,000 / 72,575
Total Engine and Tender Weight (lbs / kg)421,000 / 190,962462,200 / 209,651445,780 / 202,202377,500 / 171,231
Tender Water Capacity (gals / ML)9000 / 34.099000 / 34.098500 / 32.208500 / 32.20
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)15 / 13.6015 / 13.6017 / 15.5017 / 15.50
Minimum weight of rail (calculated) (lb/yd)84949178
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)75 / 190575 / 190573 / 185468 / 1727
Boiler Pressure (psi / kPa)180 / 12.40190 / 13.10200 / 13.80220 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)25" x 26" / 635x66026" x 28" / 660x71125" x 28" / 635x71122" x 28" / 559x711
Tractive Effort (lbs / kg)33,150 / 15036.6040,758 / 18487.5440,753 / 18485.2737,268 / 16904.50
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.54 4.16 4.01 3.78
Heating Ability
Firebox Area (sq ft / m2)186.50 / 17.33244.20 / 22.70276 / 25.65199.80 / 18.56
Grate Area (sq ft / m2)51 / 4.7455 / 5.1166.70 / 6.2058 / 5.39
Evaporative Heating Surface (sq ft / m2)2905 / 269.983625 / 336.903565 / 331.322572 / 238.94
Superheating Surface (sq ft / m2)611 / 56.78826 / 76.77918 / 85.32546 / 50.72
Combined Heating Surface (sq ft / m2)3516 / 326.764451 / 413.674483 / 416.643118 / 289.66
Evaporative Heating Surface/Cylinder Volume196.66210.68224.10208.78
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation918010,45013,34012,760
Same as above plus superheater percentage10,74112,43616,00815,057
Same as above but substitute firebox area for grate area39,27755,21466,24051,868
Power L114,22116,95020,20217,173
Power MT624.95661.39817.31805.53

Reference