During the American Civil War, when all the major locomotive works were busy producing for the war factions, the Central Pacific was in search of locomotives for its eastward expansion. Since no powerful tender locomotives could be found, the two small 4-2-4T tank locomotives with the names “C.P. Huntington” and “T.D. Judah” were purchased from Cooke. The former was named after Collis Potter Huntington, who was one of the “Big Four” and thus played a key role in the realization of the First Transcontinental Railroad.

After the procurement of more powerful locomotives, the No. 3 quickly lost importance due to its low power and small supplies and was used in front of construction trains. After being taken over by the Southern Pacific, it was assigned number 1 because of its importance and took on lighter duties in northern California. It was on display from 1888, but ended up in storage as early as 1891, only to be converted into a mobile weed incinerator ten years later.

“C.P. Huntington” in the California State Railroad Museum

Joe Ross

A new life for the locomotive began in 1910 when it was restored to working order. In the decades that followed, it participated in many parades and exhibitions, including the opening of Union Station in Los Angeles. In 1964 it was sold to the State of California, which has exhibited it at the California State Railroad Museum since 1981 after it had been at two other locations in Sacramento. Since 1960, more than 400 scaled-down replicas have been manufactured in two feet gauge, which have been available with different types of power for several years.

When the First Transcontinental Railroad was completed at Promontory Summit in Utah on May 10, 1869, the Union Pacific's No. 119 and the Central Pacific's No. 60 “Jupiter” met. CPRR President Leland Stanford was transported by the “Jupiter” on the final leg to Promontory Summit, where he hammered in the Golden Spike.

The locomotive was built in Schenectady together with the identical numbers 61 to 63 and 84 and brought to San Francisco by ship. After the ceremony, she remained in mixed service for a long time and received, among other things, a new boiler and was rebuilt from wood to coal firing. She remained in use when the CPRR was taken over by the Southern Pacific and was scrapped in 1901. After the “Genoa” and “Inyo” of the Virginia & Truckee had to serve as “Jupiter” in fairs and movies, a replica was built in 1979. This can be seen today along with the 119 at Golden Spike National Historic Park.

Although the Baltimore and Ohio had procured a locomotive with a 4-8-0 wheel arrangement in 1855 with the “Centipede”, the “Mastodon” was the first successful locomotive with this wheel arrangement. Completed in 1882, it was the heaviest locomotive in the world at the time. Shortly after its roll-out, test runs were undertaken in the Sierra Nevada with the locomotive number 229, during which, as expected, it performed significantly better than the existing Americans and Ten-Wheelers. When the operation was taken over by the Southern Pacific, it was renumbered 2925.

The shape of the boiler had some special features, including a firebox with a lower ceiling in the area of the driver's cab, which was around 13 feet long. The cylinders each had four slide valves, two of which were operated by one valve gear each. This type of cylinders was also inherited by “El Gobernator”, the even larger locomotive with 4-10-0 wheel arrangement.

Built by the Central Pacific workshops, number 229 was later sent to the Cooke Locomotive and Machine Works in New Jersey to set up series production. Depending on the source, 20 or 25 other machines were made, which had slightly larger cylinders. The first locomotive was later modernized and converted to oil firing, which probably also applies to the production locomotives. They were scrapped in June 1935.

In search of an even more powerful locomotive than the GE class with the 4-8-0 wheel arrangement, A.J. Stevens expanded this with another driving axle. The only locomotive built with this wheel arrangement was christened “El Gobernator”.

In order to still be able to run through all curves, the last driving axle was mounted so that it could be moved sideways and the third and fourth were designed without wheel flanges. The cylinders were only 21 inches in diameter, but had an extremely long stroke of 36 inches to achieve the power required. The valve gear was of a design Stevens had developed himself.

Although the locomotive was presented to the public, no use was found for this size class at the time. It also turned out that the boiler did not produce enough steam for the large cylinders. It was scrapped about ten years after completion.

At the beginning of the 20th century when the Union Pacific, Southern Pacific, Kansas City Southern and others were under the same ownership, several locomotive types were standardized in the Harriman Common Standard. One of the HCS Atlantics was the class A-3 of the Southern Pacific. 47 had been built between 1904 and 1908 by ALCO and Baldwin, of which most were oil-fired. They are said to have hauled the Daylight Limited over the 223 miles (359 km) from Los Angeles to San Luis Obispo without a refueling.

Beginning in the twenties, all were superheated. In this process, most got a feedwater heater and a trailing truck booster. In the example of the four locomotives rebuilt by the Texas & New Orleans, they even got smaller drivers with a diameter of 77 instead of 81 inches. Another four were rebuilt to the even more modern class A-6 in 1927.

All A-3 Atlantics built from 1904 onwards were fitted with a superheater from 1920 and most of them also received a feedwater heater and a booster on the trailing axle. Four underwent an even bigger rebuild in the Southern Pacific workshops, resulting in the class A-6. Two each were completed in August 1927 and October 1928.

As opposed to other rebuilds with a driver diameter of 77 inches, the A-6 retained the original 81 inches. In addition, the diameter of the cylinders was increased by two inches and the boiler pressure was increased by ten psi. The tube heating surface has been increased by about five percent and the frame has been strengthened. In total, this resulted in a service mass increased by around 20 tons. Their duties included the haulage of the Sacramento Daylight.

After the class F-1 2-10-2s, the Southern Pacific ordered 15 F-3 in 1921 from Lima. They had larger cylinders, a larger boiler and had a trailing truck booster like their predecessors. Like most SP steam locomotives, they were oil-fired. To improve running characteristics in curves, they got lateral motion boxes on the lead drivers.

Since the SP didn't want to use the name „Santa Fe” for this wheel arrangement and didn't have real Decapod locomotives, they called all their 2-10-2s “Decks” as short form for “Decapods”. In 1922, they ordered 50 very similar locomotives from Baldwin which were designated class F-4 and delivered in a single train.

All 15 F-3 were converted to coal burning in 1924. Between 1940 and 1944, they were converted back to oil burning. Both classes were retired between 1951 and 1958.

In 1930, the Southern Pacific used its Mountains as a base and installed a larger firebox, now supported by a two-axle bogie. This resulted in the GS-1, which was intended for passenger and express trains with a driver diameter of 73.5 inches or 1,867 mm and was built by Baldwin. GS stood for “Golden State” or later “General Service”. Ten GS-1 were delivered directly to the Southern Pacific and four to the Texas & Louisiana Lines.

GS-2 Nr. 4415 in January 1937 in East St. Louis, Illinois

R.J. Foster / collection Taylor Rush

In 1937 six GS-2s were delivered from Lima. They were almost identical to the GS-1, but had colorful streamlined fairing, making them about 6,000 pounds heavier. The famous GS-3 to GS-5, which had larger drivers, were later built with the same fairing. Since the GS-1 and -2 soon no longer had to pull the fastest trains, they were considered for heavy commuter trains. Especially in the San Francisco area, they had to prove their power in demanding schedules until the second half of the 1950s.

After the GS-1 and GS-2, Southern Pacific decided to design additional express locomotives in the “Golden State” series for higher speeds. By increasing the size of the drivers from 73.5 to 80 inches, the GS-3 was created, which also pulled the “Coast Daylight”. Since there were many gradients on the line between Los Angeles and San Francisco, the tractive force was compensated for by a longer cylinder stroke and higher boiler pressure.

Like the GS-2, the GS-3 stood out with its partial streamlined fairing and striking color scheme of orange, red, silver and black. After 14 GS-3s built in 1937, a total of 28 GS-4s were built in 1941 and 1942. These differed from the GS-3 mainly in a booster in the trailing bogie. They also had a faster-acting, electro-pneumatic brake, which was later removed.

During World War II, the Southern Pacific wanted to build more locomotives of this type, but the government only allowed the construction of freight locomotives. Thus, the abbreviation GS was reinterpreted from “Golden State” to “General Service”, which would indicate that these locomotives were suitable for freight and passenger trains.

In 1942 only two GS-5s were built, which now had roller bearings on all axles. The later developed GS-6 again had smaller wheels and was actually suitable for mixed service. The GS-3 to GS-5 were retired in 1957 and 1958 and largely scrapped. Among the only two members of the GS series that still exist today is the GS-4 No. 4449, which is operational.

A total of 105 of these Moguls were commissioned by the Southern Pacific beginning in 1899. They were from ALCO, most of them from Cooke and the rest from Schenectady. They were rebuilt from 1920 with a superheater. They were used in mainline service up until the 1940s and as switchers into the 1950s. Preserved today is number 1673, which is in Tucson, Arizona and has been optically refurbished since 2000.