Southern Pacific 4-8-4 "Northern" Locomotives in the USA

Southern Pacific

The Southern Pacific built a fleet of 4-8-2 Mountain type locomotives in the late 1920s in its Sacramento Shops. In 1930, the SP designed a locomotive similar to those Mountains that had a very large firebox (90.4 sq ft) and a four wheel trailing truck to support it. Thus, evolved the Southern Pacific 4-8-4 which was designated Class GS (Golden State) by the SP.

The first 10 "Golden States", Class GS-1 (road numbers 4400 through 4409), were built by the Baldwin Locomotive Works in 1930. They were oil burners with 73.5" drivers, 27 x 30 cylinders, and 250 psi boiler pressure, which resulted in a tractive effort of 62,200 lbs. They weighed 448,400 lbs and had 266,500 lbs of weight on the drivers.

In early 1937, six more "Golden States" arrived but this time from the Lima Locomotive Works. These were designated Class GS-2 and assigned road numbers 4410 through 4415 and were identical to the Class GS-1s except for the exterior styling, color scheme plus they weighed 6000 lbs more. The color scheme used bright orange, red, black and silver. The orange was applied to the pilot and in a broad band along the skirting and the tender. The red was applied in a band above the skirting and above and below the orange band on the tender. The rest of the locomotive was black except for the smoke box door, which was silver, and the hand rails, which were cadmium plated. The six Class GS-2s were purchased for brand new trains that updated passenger service between Los Angeles and San Francisco. They sported a "Daylight" emblem and regularly hauled "The Coast Daylight".

Late in 1937, 14 more "Golden States" (road numbers 4416 through 4429) were delivered from Lima. This group, Class GS-3 was similar in appearance to the GS-2s. However, they were designed for higher speeds with 80" drivers, 26 x 32 cylinders, and a boiler pressure of 280 psi giving them 62,800 lbs of tractive effort. They weighed 460,000 lbs and had 267,300 lbs over the drivers.

The Southern Pacific ordered 28 more Class GS-4 "Golden States" from Lima and took delivery of twenty (road numbers 4430 through 4449) in April and May of 1941 and the other eight (road numbers 4450 through 4457) in March and May of 1942. These were similar to the GS-3s except they had "all-weather" vestibule cabs and had a smaller cylinder diameter (25.5) with a higher boiler pressure (300 psi). They weighed 475,000 lbs and with 275,700 lbs on the drivers had a tractive effort of 64,800 pounds.

Two additional "Golden States" (road numbers 4458 and 4459), designated Class GS-5, were delivered from Lima in June of 1942 and were similar to the GS-4 except they had roller bearings on all axles and weighed 8,200 pounds more.

During World War II, the SP like most railroads were in need of more motive power and it wanted more GS Class 4-8-4s, but the War Production Board would not permit SP to build more "GS" passenger locomotives. The Southern Pacific redefined "GS" to stand for "General Service" instead of "Golden State" and specified that this group would be used for freight as well as in passenger service. The board then approved the purchase. From then on "GS" officially meant "General Service". Due to wartime shortages, these last 10 Class GS-6 (road numbers 4460 through 4469) Locomotives were built without skirting and were void of the orange and red paint and were delivered from Lima in 1943.

In 1976 4449 was one of three steam locomotives used in the American Freedom Train.

There are two survivors: number 4449, which is operational, at the Oregon Rail Heritage Center in Portland, OR and number 4460 at the Museum of Transportation in St. Louis, MO.

Texas & Louisiana

The Texas & Louisiana Lines, a subsidiary of the Southern Pacific, received the first Class GS-1 locomotives. These four "Golden States" were given road numbers 700 through 703. They had 73" drivers, 27 x 30 cylinders, a 250 psi boiler pressure, weighed 442,300 pounds and had a tractive effort of 62,200 pounds.

Roster

Qty.ClassRoad NumbersYear BuiltBuilder
10GS-14400-44091930Baldwin
6GS-24410-44151937Lima
14GS-34416-44291937Lima
20GS-44430-44491941Lima
8GS-44450-44571942Lima
2GS-54458-44591942Lima
10GS-64460-44691943Lima

Some of the Last Runs of the GS Class
Jan 22, 1957 SP GS-4 4430, San Fransisco -> San Jose, last commuter run assigned to steam
May 4, 1958 SP GS-6 4460 pulled the "Oakland-Sacramento Senator" over Sutter Basin branch north of Sacramento
Jul 27, 1958 SP GS-6 4460 deadheaded to San Fransisco then pulled the "Suntan Special" to Watsonville Jct. A diesel finished the trip to Santa Cruz over lighter rail.
The above trip was repeated three weeks later.
Oct 12, 1958 SP GS-6 4460, San Fransisco -> Fresno and return over the Dumbarton Bridge, through Niles Canyon, and down the west side of the San Joaquin Valley.
Oct 18, 1958 SP GS-6 4460, excursion from Sacramento -> Donner Pass -> Reno.
Oct 19, 1958 SP GS-6 4460, excursion from Reno -> Sacramento.

Class Details by Steve Llanso of Sweat House Media

Class GS-1 (Locobase 279)

Data from SP 7-1951 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 82, pp.566+. Works numbers were 61390-61391 in May 1930 (T & NO), 61408-61415 in June (first 2 for T & NO), and 61430-61433 in July.

First of the Golden State (or General Service) wheel arrangement. Four delivered to the Texas & Louisiana Lines. The design offered a relatively austere firebox layout with the only supplemental direct heating surface area provided by the 109 sq ft (10.1 sq m) in the combustion chamber. Boiler feed water was heated by a Worthington Type S, No. 5.

Locobase notes that the Menke book shows 2,565 sq ft (238.30 sq m) for the superheater of all of the early GS series of 4-8-4s. Each of these entries also has a page with a lower area -- 1,866 sq ft in this case -- and a revision date of 3/1/1950 or later. Locobase suspects that some of the superheater was blocked off in the late 1940s to lower maintenance costs.


Class GS-2 (Locobase 280)

Data from SP Menke All Time Steam locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also "Engines of the Coast Daylight" on the Southern Pacific Coast Daylight website at

[], both last accessed 11 April 2020. (Thanks to Chris Hohl for supplying the valve gear identification. His 25 October 2021 email pointed out the booster's TE, the correct tender water capacity), and the resulting total wheelbase.) Works numbers were 7646-7651 in 1936.

The oil-fired GS-2 is essentially a streamlined GS-1 (Locobase 279) and was the first of a series of streamliners from Lima that became steadily more colorful and powerful. The class had Worthington No 5-SA feedwater heaters.

Locobase is puzzled by the Menke book, which shows 2,565 sq ft for the superheater of all of the early GS series of 4-8-4s. Each of them also has a page with a lower area -- 1,834 sq ft in this case -- and a revision date of 3/1/1950 or later. Locobase suspects that the superheater elements were shortened in the late 1940s to lower maintenance costs by moving the rear tube bends further away from the firebox tube sheet..


Class GS-3 (Locobase 1404)

Data from SP 7-1951 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. ( "Engines of the Coast Daylight" on the Southern Pacific Coast Daylight website at

[], both last accessed 11 April 2020. Thanks to Chris Hohl for supplying the valve gear identification.) Works numbers were 7721-7731 in 1937.

As the Espee explored the implications of the power implied in the high-drivered 4-8-4 layout, they worked with Lima to recast the the GS-2 (Locobase 280). The result was a longer stroke balancing a smaller cylinder diameter; the piston speed of the longer stroke was ameliorated by a set of taller drivers. Boiler pressure rose 15% to more than compensate for the slight decrease in cylinder volume. The class also had 20" (508 mm) longer combustion chambers that added to direct heating surface area. Like the GS-2s, the -3s had Worthington No 5-SA feedwater heaters.

These were part of the well-known series of 4-8-4s that pulled most Espee long-haul passenger service and were ordered specifically to handle a new range of lightweight expresses dubbed the Noon Daylight, San Joaquin Daylight, and the Lark.

Locobase is puzzled by the Menke book, which shows 2,565 sq ft for the superheater of all of the early GS series of 4-8-4s. Each of them also has a page with a lower area -- 1,834 sq ft (170.38 sq m) in this case -- and a revision date of 3/1/1950 or later. Locobase suspects that some of the superheater was blocked off in the late 1940s to lower maintenance costs.

In a 1 November 2016 email to Wes Barris at steamlocomotive.com, Gunnar Henrioulle recalled his "last daytime view of GS-3 in action. [it]was notable. 3 consecutive (4420/4421/4422) trains working hard, about 12 hour apart, [each] with orange reefers Eastbound over the 29th & "B" Street overpass sometime in October 1956. "


Class GS-4 (Locobase 281)

Data from tables in 1947 Locomotive Cyclopedia, supplemented by diagrams from several editions of Southern Pacific locomotive diagram books supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. "Engines of the Coast Daylight" on the Southern Pacific Coast Daylight website at

[], both last accessed 11 April 2020. Works numbers were 7798-7804 in March 1941, 7805-7812 in April, 7813-7817 in May, 7848-7854 in March 1942, and 7855 in April.

GS-4s were an enlargement of the basic SP 4-8-4 GS-3 (Locobase 1440) that had fewer small tubes and 22 more flues. Boiler pressure reached an even 300 psi and engine weight grew by 7 1/2 short tons (6.8 metric tons). The boiler had a Worthington Type 5 1/2 SA feed water heater. SPCD reports that these engines were the first GSs to use "an enclosed 'all weather' cab, which engineers really appreciated on those cold nights!"

Superheater area varies considerably just among three entries in the two sources shown above. Locobase found that the earlier diagrams showed the higher value for the GS-4 and GS-5 (Locobase 6680). The 1942 diagram for the GS-4 recorded 2,565 sq ft (238.30 sq m), which constituted a whopping 34.4% of the combined heating surface area. Lima's builder's card gives a more conservative 2,086 sq ft (193.80 sq m), which equates to 30% of CHS. The 1947 Locomotive Cyclopedia listing reports the area given in the specifications in this entry.

Within the Southern Pacific diagram listings, Locobase finds a GS-4 dated 31 July 1942 that agrees with the other heating surface areas, but gives 2,565 sq ft (238.3 sq m) for the superheater area. Another diagram that shows both the 1942 revision date and a later date of 1 March 1950 reports 1,834 sq ft. Similar areas at identical dates appear in all of the GS-1,-2, -3. and -4 diagrams. Could this difference reflect the removal of some superheater elements from some of the flues some time after 1942? Perhaps more likely, the SP shortened the superheater elements themselves to move the bends further away from the firebox tube sheet.

The class was needed to handle the twelve-car Daylight over a hilly route between San Francisco and Los Angeles. Although they had 80-in drivers, the great bulk of the engine, especially with the air-smoothing casing, dwarfed the running gear. These huge engines had a broad orange valence over the wheels below a smaller red trim band that came halfway up the cab windows. They were oil-fired, used rapid-responding electro-pneumatic braking, and a trailing-truck booster that raised starting and hill-climbing tractive effort by 13,000 lb.


Class GS-5, GS-5a (Locobase 6680)

Data from SP Menke All Time Steam locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also "Southern Pacific Class GS-5 Semi-Streamlined Steam Locomotive" on the ClassicStreamliners website at []; and "Engines of the Coast Daylight" on the Southern Pacific Coast Daylight website at

[], both last accessed 11 April 2020. (Thanks to Chris Hohl for his 3 April 2020 email noting that he and Hunter Rubison supplied Lima's data card and noting several differences between that card and the Espee's diagrams, including tender weight (Hohl) and others mentioned below.) Works numbers were 7856-7857 in June 1942.

According to Classic Streamliners, "The GS-5s are identical in appearance to the GS-4s [Locobase 281], the only difference being the roller bearings that gave the locomotive a smoother ride and added weight." Like the GS-4s, the pair used Worthington 5 1/2 SA feed water heaters. Trailing truck boosters contributed 13,200 lb (5,987 kg or 58.72 kN) in starting tractive effort.

Hohl noted several levels of oil capacity in the six-axle R-2 tenders. Lima's builder's card gives 5,880 US gallons (22,256 litres) and the SP tender diagram give a maximum capacity of 6,275 gallons (23,751 litres) and a "marker bar" level of 5,978 gallons. Locobase chose the middle quantity as it was part of the SP's calculation of the tender's loaded weight in the version equipped with roller bearings..

Rubison pointed out a disparity between the builder's card superheater area (2,086 sq ft/193.80 sq m) and the 1,834 sq ft shown in the SP diagram and in Locobase's specs. As noted in the GS-4 entry, Locobase found that the earlier diagrams showed the higher value for the GS-4 and GS-5. The 1942 diagram for the GS-4 recorded 2,565 sq ft (238.30 sq m), which constituted a whopping 34.4% of the combined heating surface area. Lima's builder's card gives a more conservative 2,086 sq ft (193.80 sq m), which equates to 30% of CHS. The 1947 Locomotive Cyclopedia listing reports the area given in the specifications in this entry.

Locobase supposes that the greater complexity of the Type E superheater, which tended to plug in the tighter bends created by the smaller-diameter tubes, led to installation changes that reduced the overall superheater surface area.

Although the GS-4s used roller bearings on the engine and tender trucks, the GS-5s added them to the driving axles, main and side rods. 4458 (GS-5) was fitted with Timken bearings, 4459 (GS-5a) with SKFs. (Side-by-side photographs on the SPCD site show the Timkens' rollers could were not completely hidden by external casing; the SKF rollers were entirely shielded by thick casings.)

SPCD notes that the SP was cautious about using roller bearings, possibly because each bearing cost $27,000 more than the journal bearings. Engine and roundhouse crews noticed the reduced friction immediately. Planning ahead for a scheduled stop included earlier brake applications and roundhouse crews "knew they 'really had to tie 'em down, or they'd just start rolling away.'" Picture a 440-ton engine and tender "just rolling away" and imagine the surprise the first time that happened!

The two engines hauled the well-known SP expresses for most of their careers, hauling the Valley Daylight in later years, that service ending in 1956.


Class GS-6 (Locobase 282)

Data from SP Menke All Time Steam locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 8013-8016 in July 1943 and 8248-8253 in August.

These last ten engines in the GS series reverted to the GS-2/3 cylinder proportions and driving-wheel diameter for dual-service (freight and passenger) work. They could be seen hauling the San Joaquin Daylight and the San Jose-San Francisco Peninsula Commute service.

They were oil-fired (as were virtually all SP locomotives) and had neither streamlining nor color.. Although they lacked the splash of color, the distinctive smokebox nose, extended casing along the top, and the tall Boxpok drivers revealed their membership in the SP's GS fraternity.

The last of the class to pull a train in revenue service was class leader 4460 in 1958.

Principal Dimensions by Steve Llanso of Sweat House Media

ClassGS-1GS-2GS-3GS-4GS-5, GS-5a
Locobase ID279 280 1404 281 6680
RailroadSouthern Pacific (SP)Southern Pacific (SP)Southern Pacific (SP)Southern Pacific (SP)Southern Pacific (SP)
CountryUSAUSAUSAUSAUSA
Whyte4-8-44-8-44-8-44-8-44-8-4
Number in Class14614282
Road Numbers4400-4409, 700-7034410-44154416-44294430-44574458-4459
GaugeStdStdStdStdStd
Number Built14614282
BuilderBaldwinLimaLimaLimaLima
Year19301937193719411942
Valve GearWalschaertWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)20 / 6.1020 / 6.1021.50 / 6.5521.50 / 6.5521.50 / 6.55
Engine Wheelbase (ft / m)45.83 / 13.9745.83 / 13.9747.67 / 14.5347.66 / 14.5347.67 / 14.53
Ratio of driving wheelbase to overall engine wheelbase 0.44 0.44 0.45 0.45 0.45
Overall Wheelbase (engine & tender) (ft / m)88.23 / 26.8994.04 / 28.6696.25 / 29.34
Axle Loading (Maximum Weight per Axle) (lbs / kg)67,000 / 30,39167,000 / 30,39167,000 / 30,39169,000 / 31,29870,000 / 31,752
Weight on Drivers (lbs / kg)262,000 / 118,841266,500 / 120,883267,300 / 121,245275,700 / 125,056278,700 / 126,416
Engine Weight (lbs / kg)442,300 / 200,624448,400 / 203,391460,000 / 208,653475,000 / 215,457483,200 / 219,176
Tender Loaded Weight (lbs / kg)291,000 / 131,996373,000 / 169,190358,880 / 162,785313,730 / 142,306398,600 / 180,802
Total Engine and Tender Weight (lbs / kg)733,300 / 332,620821,400 / 372,581818,880 / 371,438788,730 / 357,763881,800 / 399,978
Tender Water Capacity (gals / ML)16,150 / 61.1721,600 / 81.8222,000 / 83.3323,300 / 88.2623,300 / 88.26
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)4690 / 17,7526275 / 23,7516010 / 22,7486275 / 23,7515978 / 22,627
Minimum weight of rail (calculated) (lb/yd / kg/m)109 / 54.50111 / 55.50111 / 55.50115 / 57.50116 / 58
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)73.50 / 186773.50 / 186780 / 203280 / 203280 / 2032
Boiler Pressure (psi / kPa)250 / 17.20250 / 17.20280 / 19.30300 / 20.70300 / 20.70
High Pressure Cylinders (dia x stroke) (in / mm)27" x 30" / 686x76227" x 30" / 686x76226" x 32" / 660x81325.5" x 32" / 648x81325.5" x 32" / 648x813
Tractive Effort (lbs / kg)63,230 / 28680.6863,230 / 28680.6864,355 / 29190.9766,326 / 30085.0066,326 / 30085.00
Booster (lbs)13,71012,51013,00013,200
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.14 4.21 4.15 4.16 4.20
Heating Ability
Tubes (number - dia) (in / mm)49 - 2.25" / 5749 - 2.25" / 5749 - 2.25" / 5745 - 2.25" / 5749 - 2.25" / 57
Flues (number - dia) (in / mm)198 - 3.5" / 89198 - 3.5" / 89198 - 3.5" / 89220 - 3.5" / 89198 - 3.5" / 89
Flue/Tube length (ft / m)21.50 / 6.5521.50 / 6.5521.50 / 6.5521.50 / 6.5521.50 / 6.55
Firebox Area (sq ft / m2)356 / 33.07356 / 33.07388 / 36.05385 / 35.77388 / 36.05
Grate Area (sq ft / m2)90.20 / 8.3890.20 / 8.3890.40 / 8.4090.40 / 8.4090.40 / 8.40
Evaporative Heating Surface (sq ft / m2)4858 / 451.494858 / 451.324890 / 454.464887 / 454.184890 / 454.46
Superheating Surface (sq ft / m2)2565 / 238.382565 / 238.292565 / 238.381834 / 170.452086 / 193.87
Combined Heating Surface (sq ft / m2)7423 / 689.877423 / 689.617455 / 692.846721 / 624.636976 / 648.33
Evaporative Heating Surface/Cylinder Volume244.37244.37248.73258.30258.46
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation22,55022,55025,31227,12027,120
Same as above plus superheater percentage30,44330,44333,91834,44235,256
Same as above but substitute firebox area for grate area120,150120,150145,578146,685151,320
Power L145,78845,78856,80749,29854,131
Power MT1541.151515.121874.121576.841712.78

Principal Dimensions by Steve Llanso of Sweat House Media

ClassGS-6
Locobase ID282
RailroadSouthern Pacific (SP)
CountryUSA
Whyte4-8-4
Number in Class10
Road Numbers4460-4469
GaugeStd
Number Built10
BuilderLima
Year1943
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)
Engine Wheelbase (ft / m)45.83 / 13.97
Ratio of driving wheelbase to overall engine wheelbase
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)67,900 / 30,799
Weight on Drivers (lbs / kg)270,300 / 122,606
Engine Weight (lbs / kg)468,400 / 212,463
Tender Loaded Weight (lbs / kg)317,800 / 144,152
Total Engine and Tender Weight (lbs / kg)786,200 / 356,615
Tender Water Capacity (gals / ML)23,200 / 87.88
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)6080 / 23,013
Minimum weight of rail (calculated) (lb/yd / kg/m)113 / 56.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)73.50 / 1867
Boiler Pressure (psi / kPa)260 / 17.90
High Pressure Cylinders (dia x stroke) (in / mm)27" x 30" / 686x762
Tractive Effort (lbs / kg)65,759 / 29827.82
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.11
Heating Ability
Tubes (number - dia) (in / mm)49 - 2.25" / 57
Flues (number - dia) (in / mm)198 - 3.5" / 89
Flue/Tube length (ft / m)21.50 / 6.55
Firebox Area (sq ft / m2)350 / 32.52
Grate Area (sq ft / m2)90.20 / 8.38
Evaporative Heating Surface (sq ft / m2)4852 / 450.93
Superheating Surface (sq ft / m2)1834 / 170.45
Combined Heating Surface (sq ft / m2)6686 / 621.38
Evaporative Heating Surface/Cylinder Volume244.06
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation23,452
Same as above plus superheater percentage29,784
Same as above but substitute firebox area for grate area115,570
Power L137,022
Power MT1207.83

Reference

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