Class E3s-45/P-12 (Locobase 8670)

Data from EP&SW 10-1924 locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.Works numbers were 57422-57431 in May 1917.

Similar to the P-6s of the Southern Pacific and the Texas & New Orleans, these EP&SW engines had more cylinder volume and considerably more superheater area. Firebox heating surface area included 29.7 sq ft (2.76 sq m) in arch tubes. They were also the heaviest Pacifics.

They were based in the Bisbee, Arizona region.

In 1924, the motive power of the EP&SW was merged with parent company Southern Pacific where they were placed in their own P-12 class. Even after the studs were combined, the P-12s had the most area of any SP Lines 4-6-2. It was then that the shops sleeved the original 27" diameter cylinders, reducing their diameters to 26" (660 mm). At the same time, they raised the boiler setting to 205 psi (14.1 bar). The combination of changes kept the calculated tractive effort very close to the original.

The entire class served through World War II. 3126 went to the scrapper in October 1947. The rest left the lines between 1949 and 1953.

Class P-1/P-3 (Locobase 4407)

Data from SP 7 - 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Reg Stocking for his 23 May 2018 email reporting the Alco provenance of the first five engines and Wes Barris of steamlocomotive.com for researching the builder's numbers.) See also data from"Report of Committe on Power-Chicago, Rock Island & Pacific Railway-Descriptions of Standard Types of Locomotives," American Engineer and Railroad Journal, Volume 79 ( March 1905), pp. 84-86.

P-1 was produced in small batches. The first five came from Alco's Schenectady Works and bore works numbers 30000-30004 in August 1904. Baldwin's began its long string of batches more than a year later, producing works numbers 27366-27369 in January 1906; 27465-66 in February; 28660, 28673-74 in July; 28714, 28737-38, 28797, 28826, 28867 in August; 30762-63, 30785-86, 30827, 30906, 30923-24 in May 1907. The identical P-3s all were manufactured in February 1911 as a single batch (36058-36067 in February 1911 ).

These Harriman Common Standard Pacifics were relatively light engines. Although they entered service with slide valves and inside valve gear, they were eventually superheated (see Locobase 8729). Eight were fitted with 23" cylinders, Walschaerts gear outside, feedwater heaters, and trailing-truck boosters in 1927-1929 and known as P-4s. See 5340 for an introduction to the basic HCS idea.

Class P-1/P-3 - superheated (Locobase 8729)

Data from SP 7 - 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange

First operated as saturated-boiler Harriman Common Standard Pacifics (see Locobase 4407), this class was superheated in a conversion that had some unusual features. The most striking was the replacement of 2 1/4" tubes with 2" tubes. The tube count didn't decline by quite so much. Moreover, when the superheater area was factored in, the engines now had more combined heating surface area than before.

Those locomotives that retained the inside Stephenson gear also retained their P-1 & P-3 designations. But eight were fitted with Walschaerts gear outside, feedwater heaters, and trailing-truck boosters in 1927-1929 and known as P-4s. They were otherwise identical to the P-1/P-3 superheated variant.

Class P-10 (Locobase 5878)

Data from [], last accessed 16 January 2010. See also DeGolyer, Volume 69, pp. 334+. (Thanks to Chris Hohl for his 30 May 2016 email noting the driver diameter as delivered as well as the loaded tender weight for the 1924 batch.) Works numbers were 57227-38, 57254-55, 57264, 57366 in October 1923 and 57630-57634, 57652-57654 in February 1924.

This class was very similar to the two-years-earlier P-8s, but had Worthington 3-B feed water heaters with capacity of 5,400 US gallons (20,439 litres) per hour. In addition, the last eight had trailing-truck booster engines. See notes on the P-8 design at Locobase 3290. The whistle was a melodious five-chamber chime. The booster was powered by superheated steam and the power reverser was an Alco Type E. The last eight locomotives were delivered with tenders weighing 236,000 lb (107,048 kg).

Page 337 features a list of "For Hereafter" notes that begin with defects in the engines already delivered and a list of changes to allow them to conform to SP shop practices. Perhaps the most important complaint concerned the mounting of the oil burner in the firebox: "Oil burner is fastened to the pan and the brace supporting the rear end of the burner and piping is fastened to the frame, so that when the boiler expands, the burner is pulled out of its natural postion. All bracing for the burner should be attached to the fire pan, which will make a more practical working proposition."

Locobase notes the oil burner specified in supplemental paragraph 97 was a Von Boden Ingles design supplied by E Sullivan of San Francisco "in accordance with Railroad company's blueprints." The Von Boden Ingles design had received a US patent number (760826) on 24 May 1904. It had been Baldwin's usual option for oil burning for decades. Locobase can't say whether other operators reported similar problems with the bracing.

The Espee steam locomotive roster and photo site

[] notes that many of these Pacifics wound up at the head of San Jose-San Francisco commuter service.

Another note from the same site: "3 P-10's were streamlined with skyline casing and side skirts in 1941, coming out looking very much like a 'baby' Gs-4. #2484-2486 were used to haul the San Joaquin Daylight between Oakland and Bakersfield." Connelly's Baldwin list shows five road numbers that were altered (2481-2482, 2488-2489, 2491).

Class P-11 (Locobase 8731)

Data from SP 7 - 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange; and DeGolyer, Volume 30, p. 251. Works numbers were 32437, 32446-32448, 32470-32473, 32502 in December 1907; 32526 in January 1908.

Pretty interesting set of small Pacifics offering relatively small compact cylinders and low drivers, but a larger boiler for the cylinder volume and a small, wide firebox.

Such dimensions didn't last very long; see Locobase 8732.

Class P-11 - superheated (Locobase 8732)

Data from SP 7 - 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works #32437, 32446-32448, 32470-32473, 32502 produced in December 1907 with 32526 following in January 1908.

Apparently the EP & SW recognized that their new Pacifics were under-powered and over-boilered. So, soon after they took delivery, the shops took out 157 tubes and replaced them with 27 large flues for the superheater. They also replaced the cylinders with larger jugs fed by 14" piston valves and rolled the locomotive on 5" taller drivers. Even the firebox was tweaked slightly with the addition of 15 sq ft of arch tubes. Although the boiler was designed for 200 psi, the railroad set the safety valve at a very precise 176 psi.

In this configuration, the class hauled its passenger trains for decades, the first of the class departing in 1939, the last surviving until 1950.

Class P-13 (Locobase 168)

Data from T&NO 3 -1932 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 82, pp. 539+. (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error.) Works numbers were 60513-60514 in June 1928 and 60564 in July.

After the T&NO bought 9 P-9s in 1923 (Locobase 8669), it returned to Baldwin five years later for another three in June-July 1928. The latter group was dubbed P-13, possibly because of the 6,500 lb (2,948 kg) weight gain.

The firebox had combustion chamber that contributed 68 sq ft (6.32 sq m) to direct heating surface and the boiler was fitted with a Worthington feed water heater. Travel in the 14" (356 mm) diameter piston valves at 75% cut-off was 6 1/2" (165 mm). Said to be near-duplicates of the P-10.

Retired in 1954-1955 from Espee's Texas lines.

Class P-14 (Locobase 8733)

Data from SP Menke All-Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also "Southern Pacific Streamliners", Railway Age, Volume 103, No 14 (2 October 1937), pp. 442-444.

Locobase 8668 showed the P-6 as it was delivered. As streamlining became the rage on railroads around the world in the 1930s, the Espee couldn't help but join the fun. They enshrouded three of their P-6s in bullet-nosed casings and set them to work pulling the Texas & New Orleans Sunbeam and the Hustler. The Sunbeam's color scheme emulated the Daylight's brilliant oranges and the effect was of a compressed GS-4 (Locobase 281) and accompanying train as it averaged 59 mph (95 kph) hurried the 264 miles (425 km) between Houston & Dallas in less than 4 1/2 hours.

Total seating capacity using the specially designed cars was 326 in four articulated coaches, a single coach, one parlor car, one diner-lounge, and a baggage car. Measuring 581 feet long without locomotive and tender (672 ft 9 3/4 in with), the Sunbeam's total train weight came to 785,610 lb (392.8 short tons or 356.8 metric tons). And "a pleasant, but persuasive, dual -tone air whistle is provided to augment the conventional six-chime steam-whistle."

One key to the higher speeds was the use of Boxpok drivers, which were easier to counterbalance and were rated at 100 mph (161 kph). As many of the motion components as possible came in a lightened form. Even so, the streamlined P-14s weighed almost ten tons more and axle loading climbed to 65300 lb )26,620 kg).

This premium service endured until 1955.

Class P-4 (Locobase 8730)

Data from SP 7 - 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange

As noted in Locobase 8729, many of the Harriman Common Pacifics were later superheated. Eight were further modified with Walschaerts gear outside, feedwater heaters, and trailing-truck boosters in 1927-1929 and known as P-4s. They also carried cylinders measuring one inch more in diameter and put 7 tons more weight on their drivers.

All of the P-4s lasted into the 1950s.

Class P-5 (Locobase 3289)

See Railway Age 2 July 1921 for data; DeGolyer, Volume 42, p. 66+; and the SP Menke All Time Steam Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange collection. Works numbers ran 38137-38144 (road 2445-2452), 38168-38169 (road 2438-2439), and 38192-38196 (road 2440-2444), all in August 1912.

These oil-burners were essentially P-3s (Locobase 4407), but with Walschaert gear. Piston valves bushed to an inside diameter of 12" (305 mm) supplied steam to the cylinders. These were the last class of Harriman Common Standard Pacifics. Vanderbilt tenders carried the water and bituminous coal.

The Texas & New Orleans also received P-5s with larger tenders in the same year; see Locobase 8666.

Retirements began in 1947 and extended to 1953.

Class P-5 (Locobase 8666)

Data from T&NO 3 -1932 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 42, pp. 54+

Produced in two batches in June 1912 (works #37959-37964 and 37981-37984), this class preceded the slightly larger P-5s (Locobase 3289) that went to the Southern Pacific in August. The 900-902 was assigned to the Morgan's Louisiana & Texas subsidiary, 903-905 went to the Louisiana Western, and 906-909 to the Texas & New Orleans.

All enjoyed a long working life with the first two going for scrap in June 1952 and the last two in November 1955.

Class P-6 (Locobase 8667)

Data from T&NO 3 -1932 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 53321-53332 in June 1913.

Apparently it was acceptable practice on the Espee to buy Pacifics from a builder other than Baldwin. This class of 12 was part of a single batch delivered both to the T&NO and to its partner (and later owner), which took six, slightly lighter engines (see Locobase 8668).

The jump in size from the P-5s delivered just a year earlier is striking. The grate is considerably larger and boiler has more tubes and flues and each has a greater diameter than its 1912 counterpart. Such evaporative generosity was occasioned by an equal increase in cylinder volume. The result was a significant step up from the Harriman Common Standard design.

Class P-6 (Locobase 8668)

Data from T&NO 3 -1932 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.(Thanks to Bob Williams for his 20 February 2021 email, which led me to correct this batch's original owners.). Works numbers were 53333-53338 in June 1913.

Locobase 8667 discusses all of the changes wrought in the Pacific design once the Southern Pacific chose to transcend the Harriman Common Pacific. This six-engine class, delivered as part of the larger order that sent twelve of the class to the T&NO (Locobase 8667), was quite similar, possessing two more tubes, but otherwise identical. These engines also had a slightly lower axle loading.

Two ex-Arizona Eastern Pacifics built to the same specifications rolled on smaller drivers and came from Lima in 1917 as a separate P-7 class; see Locobase 16530.

See Locobase 8733 for the streamlined P-14s turned out in 1937 for the T&NO from the 2455-2457. The other three remained with the SP until the mid-1950s when they were scrapped.

Class P-7 (Locobase 16530)

Data from SP Menke All Time Steam Locomotive Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Bob Williams f0r his 20 February 2021 email pointing out key differences between the Texas & New Orleans sextet and this pair.) Works numbers were 5424-5425 in 1917.

Locobase 8668 describes the six T&NO Pacifics by Brooks in 1913. Souther Pacific subsidary AE bought this pair from Lima four years later. In his email, Bob Williams pointed out the smaller drivers on the AE locomotives.

Class P-8 (Locobase 3290)

Data from "Heavy Locomotives for the Southern Pacific", Railway Age, Volume 71, No 1 (2 July 1921), pp. 15-17. See also DeGolyer, Volume 69, pp. 281+; and Paul W Kiefer, "Research and Steam Passenger Locomotives", Railway Mechanical Engineer, (September 1914), p. 345. Works numbers were 54396-54397, 54468-54480 in January 1921.

RA reported that these engines were to serve the Ogden, Utah-Carlin, Nev. section. This 247-mile stretch of road included a maximum grade of 1.5% over which one P-8 would take an eleven-car, 875-ton trailing load.

Said by Farrington (Railroading Coast to Coast, 1976) to be a duplicate of 613 on the Espee's Texas Lines. Piston valves measured 14" (356 mm) in diameter. Power reverser was the Ragonnet Type B. (The fourteen P-10s delivered in 1923 had feedwater heaters and the last eight had trailing-truck booster engines, but were otherwise similar to the P-8s; see Locobase 5878.)

RA notes the long stroke of these passenger engines and acknowledges that it's longer than was usual practice at the time. Its adoption, says RA, "was based on the results of numerous tests ... which justified the use of a longer stroke with superheated steam." RA added that the locomotives' performance had proved "that no mistake was made."

Twenty years later, Frank E Russell, Espee mechanical engineer, commented on Kiefer's New York Central results, saying that the long stroke was a result of tests on 2-10-2s with superheaters, the railroad concluded that "we should get away from saturated steam practice and that in order to obtain maximum fuel economy the cylinder diameter should be decreased and the stroke increased over the proportions normally used at that time."

Echoing the 1921 report, Russell said that these engines "were so satisfactory in passenger service, not only in high-speed hauling capacity but also in their ability to start heavy trains without taking slack, that we have continued the practice of using a relatively long stroke."

This class endured to the end of steam on the Espee, being retired in 1953-1958.

Class P-9 (Locobase 8669)

Data from T&NO 3 -1932 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 69, p. 297. Works numbers were 56313-56321 in March 1923 and 56484-56488 in May.

Baldwin produced these near-sisters of the Espee P-8s (Locobase 3290) in two 1923 batches; they preceded the Espee's own P-10s (5878) by about six months. Their cylinders also used 14" (356 mm) piston valves to supply steam and Worthington 3-B feed water heaters with 5,400 gallons/hour (20,439 litres) capacity. Compared to the SP's engines, these ran a slightly higher boiler pressure and weighed more.