Class H / Ps-3 (Locobase 6090)

Data from the 1927 New Orleans & North-Eastern locomotive diagram book supplied in March 2004 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Voume 50, pp. 249+. Works numbers were 41580-41584 in August 1914.

Built in the same year as the Class I Mikados (Locobase 6095), these were identical locomotives except for the driver size. And like the 2-8-2s, they ran on 75 lb/yard (37.5 kg/metre) rail up 1% grades and around 6 degree curves. Indeed, the Pacific quintet were next in line to the first 3 Mikes on the builder's floor.

Renumbered by the Southern in 1916 and designated Ps-3, the five rendered satisfactory service for 30 more years. Four retired in June 1947 and the class leader was withdrawn in February 1948.

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Class H/H-2 (Locobase 13797)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 35, p. 80. Richmond works numbers were 42915-42918 in 1907, Baldwin works numbers were 36411-36415 in April 1911.

The P class was the standard Pacific in the Southern system in the first decade of the 20th Century and both Richmond and Baldwin were more than willing to add to the total.

In later years under the Southern numbering system, engines in the class used one of two power combinations. 6451-6452, 6455-6457, 6459 were fitted with 24" cylinders and had their boiler pressures reduced to 200 psi. The others retained their original setup. None was ever superheated.

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Class H/H1 (Locobase 9345)

Data from the 1917 AGS MB locomotive diagram book supplied in March 2004 by Allen Stanley from his extensive Rail Data Exchange. Alco works numbers included 42915-42918 (road 251-253), ; Baldwin's were 33802-33803, 33815-33816, 33846 in September 1909 (road 248-249, 254-256).

One of surprising number of Pacifics that were delivered with saturated boilers. This design had a tiny firebox area recorded as 167 sq ft in the AGS book. The figure did not include arch tubes that added 28 sq ft to the firebox heating surface.

These were later superheated and some received 24" diameter cylinders.

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Class P (Locobase 5161)

Some data from Southern Railway diagrams hosted on southern.railfan.net/images/archive/southern/steam_loco_diagrams (viewed September 2002) and Prince (1965); DeGolyer, Volume 27, pp. 150. Alco's Richmond Works numbers were 29819-29828 in 1904. Baldwin works numbers were 23195, 23205, 23219, 23265, 23272 in November 1903; 24292-24294, 24301, 24319, 24324, 24357, 24368, 24378, 24421 in June 1904.

Compared to most of the Pacifics built for US railroads in the same period, the Southern design's firebox had one of the smallest percentage of heating surface area to total evaporative heating surface area. The Baldwins were equipped with the company's traction increaser, which shifted about 12,000 lb (5,443 kg) to the drivers.

Some of these early Pacifics were slowly converted to a Ps standard (Locobase 166) when superheated using the Universal valve chest that adapted a piston valve to the slide-valve chest. Those converted with 24" cylinders are shown above.The

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Class P (Locobase 13668)

Data fro m Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University,Volume 35, p. 80. (Thanks to Chris Hohl for finding the tender's capacity and loaded weight in the Baldwin specifications and reporting them in his 26 November 2015 email.) Works numbers were 34650-34653, 34704-34705, 34719-34720, 34735 in May 1910; 34779 in June; 35392-35393, 35415-35420, 35451-35454 in October; 35507-35514, 35559-35561, 35626 in November; and 35668 in December.

When the Southern first bought this combination of wheel arrangement and cylinder volume in 1906 (Locobase 11704), they took the first 10 ten with 63" drivers and operated them as freight engines. The other five had 72 1/2" drivers.

Four years later the Southern went back to Baldwin for another ten passenger engines, this time outfitted with outside radial valve gear. Other than that change, the formula stayed the same. This order included six more engines for the Georgia Southern & Florida; see Locobase 13669.

By 12 September 1910, a letter from R L Ettinger of the "Railway [probably the Southern] reported trouble from broken cylinders."

All but the 1242 were superheated as Ps locomotives (see Locobase 16194).

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Class P (Locobase 13669)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 35, p. 80. (Thanks to Chris Hohl for finding the tender's capacity and loaded weight in the Baldwin specifications and reporting them in his 26 November 2015 email.) Works numbers were 34780-34838 in June 1910, 35388-35391 in October 1910.

Continuing the long line of standard Southern 4-6-2s, this sextet was part of a larger order that sent ten more locomotives to the Southern itself. It repeated the relatively conservative formula of small cylinder volume, saturated boiler, slide valves, and drivers scaled for passenger service.

After the Southern took over the GS&F, these engines were renumbered in July 1915.

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Class P (Locobase 16193)

Some data from Southern Railway diagrams hosted on southern.railfan.net/images/archive/southern/steam_loco_diagrams (viewed September 2002) and Prince (1965); DeGolyer, Volume 28, p. 150; and "Pacific Type Passenger Locomotive - Southern Railway," American Engineer and Railroad Journal, Volume 80, No. 4 (April 1906), pp.144-145. Alco's Richmond Works numbers were 29819-29828 in 1904, 37610-37619 in 1905 and Baldwin works numbers 27556-27557, 27598, 27614, and 27635 in 1906.

This group repeated the P class Pacifics of 1903 (Locobase 5161). The only noticeable difference was a 1/2" (12.7 mm) driver diameter increase.

These early Pacifics were all converted to a Ps-2 standard (Locobase 166) when superheated using the Universal valve chest that adapted a piston valve to the slide-valve chest. Those converted with 24" cylinders are shown above.

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Class P-1 (Locobase 11074)

Data from "Pacific Type Passenger Locomotive", American Engineer and Railroad Journal (April 1906), pp. 144-145; 1910 List and Specification of Locomotives supplied in March 2004 and SRY 5 - 1929 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange; DeGolyer, Volume 28, p. 140 (1286-1300) and Volume 29, p. 32 (1276-1285); and Prince (1965). For the Lonesome Pine Special, see Ed Wolfe, "The Lonesome Pine Special's Journey into History", Classic Trains, Volume 6, No 3 (Fall 2005), pp. 22-29. Works numbers were 27339-27344, 27402 in January 1906; 27422, 27447-27448, 27467, 27491-27492, 27530-27531 in February; 28310, 28360, 28379-28380, 28413-28414, 28457-28458, 28491-28492 in June.

This was a class of freight Pacifics, an unusual application for a wheel arrangement predominantly adopted for passenger service. Most of the 63" engines remained essentially unchanged - they were not superheated. Four locomotives--1277-1278, 1285, and 1295--received new boilers pressed to 215 psi and 67" drivers; tractive effort for this quartet increased to 36,800 lb (16,692 kg or 163 kN).. Adhesion weight rose to 147,400 lb (66,860 kg), engine weight to 220,600 lb (100,063 kg).

Most of the class were later equipped with radial valve gear. Southern gear actuated valves on the 1275-1277, 1281-1283, 1285, 1287-1288, 1290, 1292, 1296-1297, and 1299. 1278, 1284, 1286, 1289, 1291, 1294-1295, and 1298 used Walschaert's gear.

One of the latter was 1298, which was lettered in 1926 as the Lonesome Pine Special. This engine pulled the trans-Appalachian train in far southwestern Virginia from Bristol, Va on the Tennessee border northwest to St Charles, Va, hard by the Kentucky border. Wolfe summarized the impact of the Special and the Appalachia-Bristol known as the "Short Dog": For the residents of the rural areas they served, [these trains] were lifelines to the outside world."

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Class Ps (Locobase 16194)

The Southern updated all but four of its P class locomotives (Locobases 5161, 13668, 16193) with a superheated boiler and a universal steam chest containing a piston valve. Only 1207, 1216. 1232, and 1242 were not modified.

The 1201-1240 were delivered with Stephenson link motion while the 1241-1250 used Walschaert radial gear.

Of the 46 converted, 25 were further upgraded to Ps-2. See Locobase 166.

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Class Ps-2 - Southern vg (Locobase 9412)

Some data from Southern Railway diagrams hosted on southern.railfan.net/images/archive/southern/steam_loco_diagrams (viewed September 2002), Prince (1965), and SRY 5 - 1929 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 50, pp. 288+; and Walter Smith, "The Southern Locomotive Valve Gear," Railway Review, Volume 57, No. 7 (14 August 1915), pp. 214-215.

Locobase 166 shows the larger share of the Ps-2 class, those with Walschaert gear. But the last five of the 1913-14 Baldwin order (works numbers 41347-48, 41354-56, produced in April 1914) were fitted with Southern's own design of valve gear actuating 12" (305 mm) piston valves. Richmond added works numbers 54692-54701 in July 1914 as 1350-1359.

Walter Smith described the Southern gear in the 1915 Railway Review article, first noting some of the advantages. These included fewer parts (and thus less weight) and fewer points of wear. In addition, the "transformation of rotational motion to reciprocating motion is accomplished by direct movements on straight lines." Using a straight link, which allowed the elimination of the slip in the link block, the design also eliminated any cross-head connection. Smith's diagram clearly shows the layout.

At first the Southern went all in adopting this propietary design; by the July 1915 meeting where this report was first presented, 175 locomotives had been so equipped, "the number being added to as rapidly as engines come through the shop for repairs."

Enthusiasm faded, however, and all of the surrendered their Southern gear in the 1930s in favor of the Walschaert gear setup.

Almost all of the class operated through World War II before being retired and scrapped in the late 1940s-early 1950s.

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Class Ps-2 - Walschaert vg (Locobase 166)

Some data from Southern Railway diagrams hosted on southern.railfan.net/images/archive/southern/steam_loco_diagrams (viewed September 2002) and Prince (1965). 1345 to 1359 used Southern valve gear; see Locobase 9412. (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.) Alco's works numbers for 1251-1265 were 50197-50211 in August 1911 and Baldwin's 1266-1270 were works numbers 37741-37745. In 1912, Alco's Richmond supplied 1325-1334 (works# 52314-52323). 1913-14 saw Baldwin's 1335-1344 (works 40765-770, 40788-40791, and 41347-48, 41354-56).

The Ps-2 class included new-built locomotives and 25 Ps-class engines (Locobase 16194) further upgraded with 24" cylinders and Walschaert gear.

Most built by Richmond, some by Baldwin. Ps-2 boiler pressure later increased to 195 psi, 36,872 lb TE. More than half of the earlier Ps engines (22 x 28" cyls, 220 psi, 35,000 lb TE) -converted to Ps-2 standard. Their road numbers were 1201-1203, 1208-1215, 1217, 1219-1220, 1222-1223, 1225-1227, 1230-1230, 1234, 1236, 1240, 1248, 1250, 1302, 1306-1307, 1310, 1313-1315, 1317-1319, 1321-1322. (Note: Ps-2 1311 was the second so numbered and had first entered service as CNO&TP 808 and later been renumbered 6458.)

At the same time, the Cincinnati, New Orleans, Texas & Pacific subsidiary bought 809-820 in 1911 and 1913., which were renumbered 6459-6471. The five that arrived in 1911 were works # 50212-50216; seven more -- 53271-53277 -- were delivered in 1913.

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Class Ps-4 (Locobase 167)

Data from tables in 1930 Locomotive Cyclopedia. (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 64852-63 from Alco-Schenectady went into service in 1923 as 1375-1386 followed in 1924 by Alco-Richmond's 66059-66064 -- numbered 1387-1392 and Schenectady's 66065-73, given the lower 1366-1374.

Firebox had combustion chamber, boiler had feedwater heater. Based on the USRA heavy Pacific (Locobase 173) but fitted with 73" drivers (vs 79"/2007 mm) and a shorter boiler. Compared to earlier Southern pacifics, the cylinders were more square in that the stroke remained the same, but the cylinder diameter increased. Boiler pressure was later raised to 210 psi (14.48 bar), but the railway's tractive effort value read 45,000 lb (20,412 kg).

A later batch introduced the famous Virginia Green color in 1926; see Locobase 5076.

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Class Ps-4 (Locobase 5076)

Data from Wescott (1960), SRY 5 - 1943 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange, and DeGolyer, Vol 80, pp. 690. Alco-Richmond works numbers were 66880-66902 in July 1927, Baldwin works numbers were 60461-60465 in April 1928.

It was this batch of Ps-4s that introduced the Virginia Green paint scheme to the Southern passenger power. All the lettering and striping was limned in gold and the brass and other metals highly polished. The four Washington-Atlanta locomotives bore Crescent Limited on their tenders.

Seven went to the Southern's Cincinnati, New Orleans & Texas Pacific to pull the Queen & Crescent Limited from Detroit, Cleveland, and Cincinnati through to New Orleans and other named trains to Florida such as the Royal Palm, Ponce de Leon, and Florida Sunbeam.

Four more were designated for the Alabama Great Southern.

Steam distribution came through 14" (356 mm) piston valves with an outside lap of 1 1/4"(31.75 mm), full-gear lead of 1/4"(6.35 mm), and a total travel covering 7 1/2"(191 mm). The fire box had 28 sq ft (2.6 sq m) of arch tubes and 62 sq ft (5.75 sq m) in the combustion chamber contributing to heating surface area. An cylindrical Elesco feedwater heater lay athwart the smokebox ahead of the stack.

Westcott (1960) says the Ps-4s could pull 14-car trains at 80 mph (129 km/h) even with the 73" drivers. The Smithsonian's "America on the Move" website ([], viewed 22 Sept 2004) gives the tonnage rating of the above train as 700-1000 tons on the level. (It adds: "The 'hill and dale' profile of the Charlotte Division, however, kept average speeds to about 50-60 mph.") The 150-mile run on the Charlotte Division consumed virtually all of the 14,000 gallons of water in the tender (although the train usually watered up along the way for safety's sake) and all 16 tons of coal.