St Louis-San Francisco 4-6-2 "Pacific" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 1000 (Locobase 8628)

Data from StLSF 1904, StLSF 1908 description, and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers ran from 28690-28699 in February 1904.

These were the first Pacifics on the Frisco and almost the first 4-6-2s in North America. They had small boilers and grates and rode on medium-height drivers; on the other hand, they were fitted with piston valves. Baldwin supplied another 5 in the same year.

Some time later they were superheated; see Locobase 8629.


Class 1000 - superheated (Locobase 8629)

Data from StLSF 1904, StLSF 1908 description, and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 8628 describes the first Frisco Pacifics from Brooks. Small though they were, the class was still deemed suitable for superheating. In the process, the 2 1/4" tubes were replaced by 2" tubes and a 22-flue superheating assembly installed. Unusually for such conversions, the boiler pressure remained set at 200 psi. Piston valves measured 11" in diameter.

All of the class carried on until the late 1940s. 1000 was "dismissed from service" first in September 1946. The others followed with 1005 closing out the class in December 1948.


Class 1010 (Locobase 8630)

Data from StLSF 1904, StLSF 1908 description, and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 23744, 23751-52, 23844, 23903 in March 1904.

In the same year as the Brooks Pacifics came these Baldwin Pacifics. The Brooks engines used piston valves, the Baldwins continued with slide valves. Otherwise, the two designs were quite similar. Locobase noted that the 1904 diagrams showed clearly a firebox heating surface area of 102.5 sq ft. As small as that figure is, he has retained it because he can find no documentation for another number. Later this class was credited with 171.1 sq ft, but that included 2 Nicholson thermic syphons.

Some time later this class superheated; see Locobase 8631.


Class 1011 - superheated (Locobase 8631)

Data from StLSF 1904, StLSF 1908 description, and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 23744, 23751-52, 23844, 23903 in March 1904.

The Frisco's makeover of the Brooks locomotives (Locobase 8630) took significant liberties with the original design. What they did to the Baldwins ran even deeper. The same reduction in tube diameter occurred - from 2 1/4" to 2"and the cylinders were bored out to 21". But the superheater ratio ran even higher as more small tubes were sacrificed for superheater flues and elements. At the same time, the slide valves of the original design were replaced by relatively capacious 12" piston valves. Moreover, the firebox was extensively reworked, gaining 2 Nicholson thermic syphons in the process.

Of the class, the last 4 were retired beginning in March 1949 and ending in September 1951.


Class 1015 - delivered (Locobase 13528)

Data from Baldwin Locomotive Works Specification for Engines, 1888, as digitized by the DeGolyer Library of Southern Methodist University, Volume 33, pp. 218-219. Works numbers were 34154-34159, 34193-34195, 34209-34212, 34227, 34234 in January 1910; 34251-34253, 34265, 34328 in February 1910 35275-35278 in September; and 35352 in October. (Thanks to Antonio Fontanelli, whose 3 March 2013 email pointed out a discrepancy in the builder's numbers.)

These were among the first North American locomotives to be delivered with superheaters. Notice the low boiler pressure of 160 psi, a setting probably derived from an expectation that superheating steam would allow a reduction of boiler pressure. (Later thinking said, "Take both the superheat and the higher pressure for even more power and accept the higher maintenance cost.").

The boiler would be substantially made over; the result is seen in Locobase 8632.


Class 1015 - rebuilt (Locobase 8632)

Data from StLSF 1908 description, StLSF 1930, StL&SF 11 - 1943, and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 13528 details this class as it was delivered in 1910. When the Frisco overhauled the set some time in the late 1920s and early 1930s, they went with a new boiler that had smaller-diameter tubes. Fourteen -- 1015, 1019, 1021, 1023, 1025, 1036, 1027, 1033, 1031, 1034-1035, 1016, 1018, 1017 -- were fitted with 24"-diameter cylinders and boilers pressed to 200 psi. Thus, although the cylinder volume dropped, the increase in BP increased tractive effort. Five retained Walschaert valve gear; the rest were refitted with Baker gear.

Three--1018, 1025, and 1031--would be streamlined in 1939; see Locobase 8633. Three more locomotives--1025, 1034, and 1036 -- would share the power dimensions.

The class stayed in service for about 40 years each and were "dismissed from service" between 31 May 1949 and 11 December 1951.


Class 1018 streamlined (Locobase 8633)

Data from StLSF 11 - 1943 and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 8632 describes the original class of Pacifics from which this small group of rebuilds was drawn. The three were taken in hand to properly grace the Firefly, a new streamlined train service between Kansas City and Oklahoma City via Tulsa. Note the variety of tweaks applied to a design that already had garnered smaller cylinders and a higher boiler pressure: taller drivers, oil-burning firebox, a bigger tender, and substantially more weight on the drivers and overall. 1018 & 1031 had Walschaert gear, 1026 had Baker gear.

The streamline casing that now shrouded the boiler had a bullet nose, faired stack, and thick valence over the open running gear. A broad band of color along the valence and the tender was simply lettered "Frisco Lines." As Drury (1993) points out, "Streamlined or no, the bell and the whistle were out front where they could be heard."

As far as pictures can show, the trio retained their shrouds throughout the rest of their careers. 1026 was first to be "dismissed from service" on 31 May 1949. 1031 followed on 4 October while 1018 ran until 22 May 1950.


Class 1040 (Locobase 7586)

Data from reproduction of 1913 Alco Bulletin 1016 on Richard Leonard's http://www.railarchive.net/alcopacifics/index.html (accessed 16 June 2006). Data also from StLSF 1930, StL&SF 11 - 1943, and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

According to Drury (1993), this class of Pacifics (works# 50553-50572) shared many components with the 1306-class Consolidations. Later, the Frisco rebuilt this class into oil-burners with 24" x 28" cylinders and 73" drivers; see Locobase 8634.

They were "dismissed from service" in the 13 months between 30 November 1950 and 27 December 1951.


Class 1040 - rebuilt 69"" (Locobase 8634)

Data from StLSF 1930, StL&SF 11 - 1943, and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Most of the class profiled in Locobase 7584 was reworked in the late 1920s and early 1930s. Almost all were converted to oil-burning beginning in 1924, cylinder diameter dropped by 2 inches, boiler pressure rose by 30 psi, and the brick arch was removed from the firebox. This last alteration was offset by installation of a Nicholson thermic syphon, which increased firebox heating surface. One of this class rode on 73" drivers.

Five others had a further makeover; see Locobase 8635.

They were "dismissed from service" in the 13 months between 30 November 1950 and 27 December 1951.


Class 1042 - rebuilt 73"" (Locobase 8635)

Data from StLSF 1930, StL&SF 11 - 1943, and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 8634 shows the results of the Frisco's rebuilding program in the late 1920s and early 1930s. For seven of the locomotives, that was not the end of the makeover. Tubes were removed in favor of more superheater area, which now achieved superpower proportions.


Class 1060 (Locobase 8535)

Data from reproduction of the Frisco Man newsletter, Vol XI, # 7 (July 1917), pp. 13-16, found on the Frisco Lines history website -- http://198.209.8.207/lochist/frisco/magazines/fm_1917_07/fm_1917_07.pdf, accessed 4 July 2007. (Thanks to Chris Hohl for his 24 October 2015 email describing the change from Baker to Walschaert gear.) See also DeGolyer, Vol 55, pp. 273+. Works numbers were 45358, 45387 in March 1917; 45464-45466, 45511-45512 in April; 45580, 45631 in May; and 45701 in June.

According to the Frisco Man article, these new Pacifics were fitted with the Jacobs-Shupert welded firebox. The author then gives a detailed description of the construction of this unusual variation. Among other features were the 13"-diameter (331 mm) piston valves, Street mechanical stoker, and Ragonnet power reverse mechanism.

Certainly in comparison with the earlier class of Frisco Pacifics, these were much bigger and more powerful locomotives. But the fireboxes leaked, which sapped the design's potential. There may also have been issues with the Baker valve gear; Chris Hohl points out that the 1060s were refitted with Walschaert's gear before they were extensively rebuilt.

Two decades after their delivery (they didn't want to rush things?), Frisco reconstructed the class as bigger and better 4-6-4s; see Locobase 165.

Specifications by Steve Llanso of Sweat House Media
Class10001000 - superheated10101011 - superheated1015 - delivered
Locobase ID8628 8629 8630 8631 13,528
RailroadSt Louis-San Francisco (Frisco/(SLSF)St Louis-San Francisco (Frisco/(SLSF)St Louis-San Francisco (Frisco/(SLSF)St Louis-San Francisco (Frisco/(SLSF)St Louis-San Francisco (Frisco/(SLSF)
CountryUSAUSAUSAUSAUSA
Whyte4-6-24-6-24-6-24-6-24-6-2
Number in Class10105525
Road Numbers1000-10091000-10091010-10141010-10141015-1039
GaugeStdStdStdStdStd
Number Built10525
BuilderAlco-BrooksFriscoBurnham, Williams & CoFriscoBaldwin
Year19041904190419301910
Valve GearWalschaertWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.33 / 3.7612.33 / 3.7612.33 / 3.7612 / 3.6612.50 / 3.81
Engine Wheelbase (ft / m)31.50 / 9.6031.67 / 9.6530 / 9.1430 / 9.1432.75 / 9.98
Ratio of driving wheelbase to overall engine wheebase 0.39 0.39 0.41 0.40 0.38
Overall Wheelbase (engine & tender) (ft / m)60 / 18.2957 / 17.3760.72 / 18.5162.12 / 18.9364.75 / 19.74
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)123,400 / 55,973139,400 / 63,231118,800 / 53,887131,700 / 59,738145,000 / 65,771
Engine Weight (lbs / kg)193,550 / 87,793204,900 / 92,941191,000 / 86,636210,100 / 95,300212,000 / 96,162
Tender Loaded Weight (lbs / kg)134,200 / 60,872134,200 / 60,872134,200 / 60,872165,200 / 74,934151,800 / 68,855
Total Engine and Tender Weight (lbs / kg)327,750 / 148,665339,100 / 153,813325,200 / 147,508375,300 / 170,234363,800 / 165,017
Tender Water Capacity (gals / ML)6000 / 22.736000 / 22.736000 / 22.737500 / 28.418100 / 30.68
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)13 / 11.8013 / 11.8013 / 11.8013 / 11.8011.50 / 10.50
Minimum weight of rail (calculated) (lb/yd / kg/m)69 / 34.5077 / 38.5066 / 3373 / 36.5081 / 40.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)69 / 175369 / 175369 / 175369 / 175369 / 1753
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80200 / 13.80200 / 13.80160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)20" x 26" / 508x66021" x 26" / 533x66020" x 26" / 508x66021" x 26" / 533x66026" x 28" / 660x711
Tractive Effort (lbs / kg)25,623 / 11622.4128,250 / 12814.0025,623 / 11622.4128,250 / 12814.0037,307 / 16922.19
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.82 4.93 4.64 4.66 3.89
Heating Ability
Firebox Area (sq ft / m2)164 / 15.24146.70 / 13.63102.50 / 9.53171.10 / 15.90185 / 17.19
Grate Area (sq ft / m2)42.10 / 3.9142.10 / 3.9143 / 443.30 / 4.0251 / 4.74
Evaporative Heating Surface (sq ft / m2)2958 / 274.912342 / 217.662928 / 272.122112 / 196.282851 / 264.86
Superheating Surface (sq ft / m2)531 / 49.35602 / 55.95626 / 58.16
Combined Heating Surface (sq ft / m2)2958 / 274.912873 / 267.012928 / 272.122714 / 252.233477 / 323.02
Evaporative Heating Surface/Cylinder Volume312.89224.70309.71202.63165.70
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation84208420860086608160
Same as above plus superheater percentage84209936860010,5659629
Same as above but substitute firebox area for grate area32,80034,62120,50041,74834,928
Power L1919117,332837018,50410,063
Power MT492.61822.32465.98929.25459.00

Specifications by Steve Llanso of Sweat House Media
Class1015 - rebuilt1018 streamlined10401040 - rebuilt 69""1042 - rebuilt 73""
Locobase ID8632 8633 7586 8634 8635
RailroadSt Louis-San Francisco (Frisco/(SLSF)St Louis-San Francisco (Frisco/(SLSF)St Louis-San Francisco (Frisco/(SLSF)St Louis-San Francisco (Frisco/(SLSF)St Louis-San Francisco (Frisco/(SLSF)
CountryUSAUSAUSAUSAUSA
Whyte4-6-24-6-24-6-24-6-24-6-2
Number in Class25320157
Road Numbers1015-10391018, 1026, 10311040-10591040-10591042, 44-45, 51, 59
GaugeStdStdStdStdStd
Number Built20
BuilderFriscoFriscoAlco-SchenectadyFriscoFrisco
Year1939191219291930
Valve GearBakerBaker or WalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.50 / 3.8112.50 / 3.8112.50 / 3.8112.50 / 3.8112.50 / 3.81
Engine Wheelbase (ft / m)32.75 / 9.9832.75 / 9.9833.08 / 10.0833.12 / 10.0933.12 / 10.09
Ratio of driving wheelbase to overall engine wheebase 0.38 0.38 0.38 0.38 0.38
Overall Wheelbase (engine & tender) (ft / m)64.72 / 19.7369.87 / 21.3056.94 / 17.3665.98 / 20.1165.98 / 20.11
Axle Loading (Maximum Weight per Axle) (lbs / kg)63,150 / 28,644
Weight on Drivers (lbs / kg)145,500 / 65,998153,700 / 69,717158,000 / 71,668159,200 / 72,212178,850 / 81,125
Engine Weight (lbs / kg)225,500 / 102,285239,200 / 108,499260,500 / 118,161262,600 / 119,113296,750 / 134,604
Tender Loaded Weight (lbs / kg)151,800 / 68,855208,000 / 94,347161,200 / 73,119175,600 / 79,651211,100 / 95,753
Total Engine and Tender Weight (lbs / kg)377,300 / 171,140447,200 / 202,846421,700 / 191,280438,200 / 198,764507,850 / 230,357
Tender Water Capacity (gals / ML)8100 / 30.6810,000 / 37.888100 / 30.688100 / 30.6810,000 / 37.88
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)11.50 / 10.503800 / 14.4014 / 12.704000 / 15.204000 / 15.20
Minimum weight of rail (calculated) (lb/yd / kg/m)81 / 40.5085 / 42.5088 / 4488 / 4499 / 49.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)69 / 175373 / 185469 / 175369 / 175373 / 1854
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80175 / 12.10205 / 14.10205 / 14.10
High Pressure Cylinders (dia x stroke) (in / mm)24" x 28" / 610x71124" x 28" / 610x71126" x 28" / 660x71124" x 28" / 610x71124" x 28" / 610x711
Tractive Effort (lbs / kg)39,736 / 18023.9737,558 / 17036.0440,805 / 18508.8640,729 / 18474.3938,497 / 17461.97
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.66 4.09 3.87 3.91 4.65
Heating Ability
Firebox Area (sq ft / m2)214 / 19.88215.70 / 20.05204 / 18.96236.40 / 21.97236.40 / 21.97
Grate Area (sq ft / m2)50.90 / 4.7350.90 / 4.7350.90 / 4.7350.90 / 4.7350.90 / 4.73
Evaporative Heating Surface (sq ft / m2)2831 / 263.012780 / 258.363676 / 341.643692 / 343.123743 / 347.86
Superheating Surface (sq ft / m2)679 / 63.08679 / 63.10759 / 70.54833 / 77.421041 / 96.75
Combined Heating Surface (sq ft / m2)3510 / 326.093459 / 321.464435 / 412.184525 / 420.544784 / 444.61
Evaporative Heating Surface/Cylinder Volume193.10189.62213.65251.83255.31
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,18010,180890810,43510,435
Same as above plus superheater percentage12,11412,21610,42212,31312,730
Same as above but substitute firebox area for grate area50,93251,76841,76957,18559,124
Power L115,70716,54713,48319,89324,318
Power MT713.98712.03564.40826.44899.28

Specifications by Steve Llanso of Sweat House Media
Class1060
Locobase ID8535
RailroadSt Louis-San Francisco (Frisco/(SLSF)
CountryUSA
Whyte4-6-2
Number in Class10
Road Numbers1060-1069
GaugeStd
Number Built10
BuilderBaldwin
Year1917
Valve GearBaker
Locomotive Length and Weight
Driver Wheelbase (ft / m)13 / 3.96
Engine Wheelbase (ft / m)33.92 / 10.34
Ratio of driving wheelbase to overall engine wheebase 0.38
Overall Wheelbase (engine & tender) (ft / m)71.58 / 21.82
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)190,000 / 86,183
Engine Weight (lbs / kg)296,000 / 134,264
Tender Loaded Weight (lbs / kg)190,000 / 86,183
Total Engine and Tender Weight (lbs / kg)486,000 / 220,447
Tender Water Capacity (gals / ML)10,000 / 37.88
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)18 / 16.40
Minimum weight of rail (calculated) (lb/yd / kg/m)106 / 53
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)73 / 1854
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)26.5" x 28" / 673x711
Tractive Effort (lbs / kg)45,791 / 20770.47
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.15
Heating Ability
Firebox Area (sq ft / m2)284 / 26.38
Grate Area (sq ft / m2)63.50 / 5.90
Evaporative Heating Surface (sq ft / m2)4200 / 390.19
Superheating Surface (sq ft / m2)996 / 92.53
Combined Heating Surface (sq ft / m2)5196 / 482.72
Evaporative Heating Surface/Cylinder Volume234.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation12,700
Same as above plus superheater percentage15,113
Same as above but substitute firebox area for grate area67,592
Power L119,854
Power MT691.11

Reference