Class 2512 (Locobase 5316)

Data from report of Tests of Locomotives at the Louisiana Purchase Exposition published in Transactions of the American Society of Mechanical Engineers (Volume 27 - 1906), pp. 617-618. See also "Locomotive for Experiment, Pennsylvania Railroad," Railway Master Mechanic, Vol XXX, # 2 (February 1906), pp. 42-46. (Thanks to Chris Hohl for his 14 March 2018 email noting the tender's capacities.)

De Glehn compound bought from the Alsatian firm that built most of those in French service. Compared to US compound Atlantics, the boiler's sizable enough but the grate at the base of the Belpaire firebox was quite small. Also note the relatively small drivers. The committee that led the tests noted that during those trials on the test stand, the "...whole locomotive was unusually steady at all speeds, having very little motion of any kind."

Designed under a different philosophy from most US engines (but possessing a Belpaire firebox, like most other Pennsy locomotives), the 2512 had the large-diameter, internally finned Serve boiler tubes, a relatively high boiler pressure, and splashers with slots over the drivers.

RMM commented that it was "...a lighter machine than its American prototypes, and exemplifies the refinements worked out by ... DeGlehn in producing a locomotive with a minimum weight of driving gear by dividing the working stresses between the driving axles." That is, the HP cylinders were placed outside and drove the rear coupled axle while the LP cylinders lay between the frames and drove the leading coupled axle. Each of the four cylinders was driven by its own set of valve gear.

Never truly suited for PRR operation, the 2512 had a short term of service, being retired in 1912.

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Class E (Locobase 13123)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 30, p.203. Works numbers were 30370-30371 in March 1907.

Although in size these were repeats of the pair of 1899 Atlantics shown in Locobase 12355, the 1907 engines had more cylinder volume and a higher boiler pressure. They also were specified to have 72" drivers. Also in contrast to the haste with which the Pennsy disposed of the earlier engines was the decision instead to add superheaters to both locomotives in August 1923.

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Class E / Eodd (Locobase 12355)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 22, p.119. Works numbers were 16885-16886 in July 1899.

Locobase considers this pair of undersized Atlantics as Eight-wheelers with an extra truck under the firebox. They certainly didn't have most of the high-stepping, big-grate qualities of the classic express engine. After 20 years on the PNY & N, the Es went on the Pennsylvania's books as 06513 and 06516. 06513 was scrapped almost immediately while 06516 was sold in February 1922.

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Class E1 (Locobase 3877)

Data from "Atlantic Type Locomotive--Class E-1, No. 698", Railroad Gazette, Volume XXX1, No. 27 (7 July 1899), pp. 487-488; "Atlantic Locomotive for the Pennsylvania Railroad", Railway and Engineering Review, Volume XXXIX [39], No 34 (26 August 1899), pp. 474; and "Atlantic Type Fast Passenger Locomotives-E1-Pennsylvania", American Engineer and Railroad Journal, Volume 74, No 1 (January 1900), pp. 22-23. See also Paul T Warner, "The Development of the Anthracite-Burning Locomotive", Railway & Locomotive Historical Society Bulletin, Volume 52, pp. 11-28, as archived on [] . (Thanks to Chris Hohl for his 13 December 2020 email supplying two citations and several corrections.)

Comments in an article on the E-2, describes an "unsatisfactory cab arrangement of the class E-1" although the author does not elaborate. Locobase concludes that such a big grate meant that the fireman and engineer couldn't communicate across the footplate very easily.

In fact, [] (last accessed 20 February 2007) shows that this was a camelback with a Wooten firebox, a very rare type on the Pennsylvania. Locobase contends that this is one of the most stylish looking camelbacks, possibly because the cab rides relatively low on the boiler and the dome, stack, and headlight stand tallest on the profile.

Paul T Warner asserted that it was "...safe to say that, at the time of their construction, they represented the most careful designing and the f [49inest workmanship that could be found in this country. They met the 60-minute schedule without difficulty and demonstrated their ability to easily maintain an average speed of 75 miles an hour from Hammonton to Drawbridge, a distance of 27.4 miles, with trains weighing 300 tons behind the tender. "

Walter Mason Camp's R&ER report cited another example of the design's power and speed when it took "a 410-ton passenger train 33 miles in 35 minutes [56.6 mph/91 kph) from start to stop, and ...the entire run of 90 miles from Philadelphia to Jersey City in 109 minutes [49.5 mph/80 kph ]" including stops. "[A]t not time was it fully let out."

In the article cited above, Warner described the firebox in great detail, reporting that it "... had a combustion chamber with a brick wall built across the back of it, in accordance with Mr. Wootten 's design, but following Pennsylvania practice the Belpaire System of staying was employed. The crown and roof sheets were flat and horizontal, and the water spaces were of liberal width throughout. The grates were of the rocking type arranged to shake in four sections, and particular attention was given to the arrangement of the ash-pan and smoke-box. All these features contributed to the success of the locomotives."

Camp noted another advantage of the combustion chamber in increasing the distance of the flues from "the body of the fire". The effect, he added, would to "considerably increasae their life and lessen the tendency to leak after an exceptionally severe trip."

Long travel valves offered "an unusually large inside clearance of 5.32 in on each side," Camp noted, and as "the link motion has a remarkably good scheme all the way up the quadrant, the engine should, and does, clear itself very freely while running at high speed." Such absence of choking, he contended, was "a matter of vital importance in this service."

Warner also called its construction the "high-water mark in the development of the hard-coal burning locomotive."

And yet their design was not repeated as a camelback. Locobase notes that the Pennsy only tried out the camelback layout a few times, disliking the separation of the two crew members.. The long combustion chamber so vaunted by the analysts soon lost favor in camelback design and no other engine combined camelback and Belpair firebox. And very few Pennsy designs featured much of a combustion chamber until the M1 4-8-2s and the T1 4-4-4-4s. The strains imposed on "unusually long main rods" and lightly built components in the drive train may have demanded more maintenance time than their performance merited.

Regardless of the actual blend of causes, the three locomotives were sent to the Long Island where they served only a few years before being scrapped in 1911.

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Class E2 (Locobase 3878)

Data from "The Pennsylvania's Class E2 Experimental Locomotive," Railroad Gazette, Volume XXXII, No. 29 (29 July 1900), pp.492-493;"The Pennsylvania Class E-2 Locomotive," Railroad Gazette, Volume XXXII, No 29 (29 July 1900), p. 605; "The New Class E2 Locomotive--Pennsylvania Railroad," Railroad Gazette, Volume XXXIII, No. 24 (14 June 1901), pp.409-410; and from PRR Steam Locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

The RG articles reported that "new features had been introduced in the spring rigging [caused] the engine to ride very smoothly on tracks in the ordinary condition, but with perfect ease on the roadbed of the West Jersey & Seashore, which is the nearest approach to perfection which can be produced."

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Class E28/E2B (Locobase 115)

Data from Bruce (1952), supplemented by DeGolyer, Volume 7, p. 267.. See also "Locomotive for Experiment, Pennsylvania Railroad," Railway Master Mechanic, Vol XXX, # 2 (February 1906), pp. 42-46. (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 25548 in April 1905, 25606 in May.

Unusual Pennsy locomotives in that they used balanced four-cylinder compoundng based on Alfred de Glehn's divided drive layout in which the inside, high-pressure cylinders drove the first axle and the outside, low-pressure ones drove the second driver set. Valve motion was inside with each 15"(381 mm)-diameter piston valve feeding the two cylinders on each side.

Like most PRR locomotives, it had a Belpaire boiler. Compared to the Alcos described in Locobase 5382, these had fewer but larger-diameter tubes in the boiler. They were otherwise virtually identical.

Adding a layer of comparison among the four balanced compounds, the Pennsy sent one of each builder's pair to the Lines East in Pennsylvania and one to the Pittsburgh, Fort Wayne & Chicago subsidiary in the Lines West region. As with the Alcos, the Lines East engine 2759 was never simpled and went for scrap in September 1917. The Lines West engine 7451 was simpled and placed in class E2b. In 1923 it was reclassified E7s in recognition of its superheater upgrade, but went to the scrapper in November 1925.

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Class E29/E2B (Locobase 5382)

Data from table in the June 1907 issue AERJ. See also "Locomotive for Experiment, Pennsylvania Railroad," Railway Master Mechanic, Vol XXX, # 2 (February 1906), pp. 42-46. Works numbers were 31245 in August 1905 and 37776 in September..

In the same year that the Pennsy bought two Baldwin balanced compounds, Alco delivered two Cole four-cylinder compounds. Valve motion was inside and like most PRR locomotives, it had a Belpaire boiler. The HP cylinders inside drove the front axle, the outside LP cylinders drove the second axle.

Locobase 115 shows the Baldwin variant that had larger-diameter tubes.

As noted in Locobase 115, the Pennsy divided the balanced compound pairs, sending one of each builder's pair to the Lines East in Pennsylvania and one to the Pittsburgh, Fort Wayne & Chicago subsidiary in the Lines West region. As with the Baldwins, the Lines East engine 2776 was never simpled and went for scrap in September 1917. The Lines West engine 7452 was simpled and placed in class E2b. In 1923 it was reclassified E7s in recognition of its superheater upgrade, but went to the ferro-knacker in April 1925.

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Class E2A (Locobase 8415)

Data from 1908 Annual Convention of the American Railway Master Mechanics Association (in Atlantic City), p. 300, and from table in AERJ July 1903.

The website [] (visited 5 February 2003) hosts Bob Berkey's corrected PRR roster and is the source for the number in the class and for the fact that as built the Belpaire-boilered engine had slide valves and Stephenson valve gear. Although Altoona supplied most of these Lines West engines, Schenectady contributed 32. Ten of the Alcos had piston valves.

A total of 25 of these engines were later converted to other classes, being superheated in the process: E3sa (2), E3sd (10), and E7s (13).

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Class E2d (Locobase 8416)

Data from Classification of Locomotives and Tenders, No. 109-H (1925), Pennsylvania Railroad, p. 8, supplied by Allen Stanley (PRR 11-1925 109-H). See also 1908 Annual Convention of the American Railway Master Mechanics Association (in Atlantic City), p. 301.

These Atlantics were virtually identical to the E2a supplied a few years earlier, but there were interesting differences. For one thing, the E2ds had 12" (305 mm) piston valves actuated by the then-controversial Walschaert gear. Also, the E2ds concentrated their weight much more firmly on the driving axles, taking 5 tons (4,536 kg) away from the three carrying axles.

All but three were superheated in the mid-'teens; see Locobases 9483 (E2sd) and 432 (E3sd).

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Class E2sd (Locobase 9483)

Data from Classification of Locomotives and Tenders, No. 109-H (1925), Pennsylvania Railroad, p. 8, supplied by Allen Stanley (PRR 11-1925 109-H).. See also Rob Schoenberg's scanned-in diagrams at [] (visited 5 February 2003) and PRR Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

As the Pennsy superheated its large stud of saturated Atlantics, it adopted a standard boiler for all of the earlier classes. In the case of the E2sd, the familiar Belpaire firebox and 12" (305 mm) piston valves remained as did the original cylinder volume.

As usual in North American superheater conversion projects, the boiler lost almost half of its 2" tubes in favor of 24 larger flues.

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Class E3a (Locobase 5329)

Data from [] (visited 5 Feb 2003) and AERJ July 1903. The website [] (visited 5 February 2003) hosts Bob Berkey's corrected PRR roster and is the source for the number in the class and for the fact that as built the Belpaire-boilered engine had slide valves and Stephenson valve gear.

A total of 15 of these engines were later converted to other classes, being superheated in the process: E3sa (11), E3sd (4).

It's not clear from Rob Schoenberg's diagram at what boiler pressure the E3a ran. It's grouped with the E2a, which AERJ data tells us pressed 205 psi. But its cylinders are 1 1/2" larger, which either translated into that much more tractive effort or a lower boiler pressure for the same TE. In fact, another diagram shows the engines ran at either 195 or 205 psi.

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Class E3sd/E4s/E5s (Locobase 452)

Data from Rob Schoenberg's scanned-in diagrams at [] (visited 5 February 2003).

Boiler pressure, driving wheel diameter, and grate area were the same for all Pennsy E-types, but the subclasses reflect differences in piston diameters, round-topped or Belpaire fireboxes. E-3d began life with 205-psi operating pressure and a saturated boiler (see Locobase 5329), later reduced to 195 psi during the addition of superheat in 1912-1914 Most E-2d-class engines (Locobase 8416) also were converted to E-3sd. Piston diameter of E-series before E-6 eventually standardized at 22 in.

Note that E4s and E5s were heavier at 208,000 lb engine weight.

NB: There's a mysterious disagreement within Stanley's diagram collection. For the E2 through E5 classes, superheater flue diameters differ depending on diagram. For some it's 5 1/2", for others 5 3/8". Even odder, the 5 3/8" version is credited with much more superheater area than the 5 1/2" diagrams, even allowing for the "equivalent superheater" calculation briefly in vogue that credited superheaters with 1 1/2 times as much area as a similar area of small tubes.

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Class E6 (Locobase 16457)

Data from "A New Atlantic Type Locomotive Built by the Pennsylvania RR", Railway Review, Volume 51, No 9 (4 March 1911), pp. 175-176. Works number was 2179 in December 1911.

This locomotive's design illustrates the care with which the Pennsylvania's Alex Vogt approached locomotive innovation. Not all passenger locomotives in the Pennsy's vast system required the power offered by the new Pacifics. Atlantics could serve on a "class of service, consisting of the very best and fastest, though not the heaviest, trains for which the lighter engine ...is much to be preferred." The Pennsylvania Special's 18-hour schedule from New York to Chicago was a good example.

E3 class engines provided the basic power dimensions under a much larger boiler. Vogt traded length for quantity "to produce a steam generator of unquestioned reliabilty", the RR reported. 14" (356 mm) piston valves admitted that steam to the cylinders.

The E6 gained a short period of fame for its size, power, and speed, but it was soon clear that a superheated boiler would do that much and more through drier steam. See Locobase 109 for the world-famous E6s that appeared in 1914.

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Class E6s (Locobase 109)

Data from PRR Steam Locomotive Diagrams, prepared by Robert Schoenberg, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also Pennsylvania Railroad, Comparison of Passenger Locomotives, Locomotive Testing Plant Bulletin No. 22 (Altoona, Pa: Pennsylvania Railroad Company, 1915); and Pennsylvania Railroad, "Classification and Description of Locomotives and Tenders -- No. 109-H", issued November 16, 1925, p. 18 supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection. (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 . Hohl's 14 October 2019 email noted differences in tender capacities and superheater area measurements.) Juniata works numbers were 2779-2815, 2817-2824, and 2826-2860, all between February and August 1914.

These engines were a development of the earlier E3s and the single E6 from 1911 (Locobase 16457). Chief Mechanical Engineer Axel Vogt wrung still more power out of the E3 design by enlarging the boiler diameter from 65 to 76 inches and adding a combustion chamber to the firebox. The E6s boosted the E6's power by increasing piston diameters by 1 1/2" ( 39 mm), , and installing a superheater. Surprisingly, the deletion of 236 tubes in favor of 242 tubes of 12" greater length and 36 5 1/2" flues achieved very nearly the same amount of combined heating surface area.

The piston load per pound of reciprocating parts was 83 lb (37.65 kg), according to Railway Age (21 July 1916), which was 5.1% more than the Reading Pacifics. The Locomotive Testing Plant bulletin reported that savings in steam consumption of between 27% at 1,100 ihp and 31% at 1,700 ihp.

Richard M. Gladulich summarizes the impact of the superheater in his Pennsylvania Railroad Museum ([], 17 August 2004) description of the E6:

"The effect of the superheater on the E6 design was astounding. During four years of testing at the PRR Altoona Test Plant, the superheated E6 demonstrated a 30% increase in power, with a corresponding 23% to 46% drop in water and coal consumption, depending on train weight and track gradient." Notable, too, was the patience with which Pennsy engineers would examine a proposed innovation.

Hohl's comment observed that some sources gave the superheating surface area as 721 sq ft (66.98 sq m) and others 613 sq ft. PRR diagrams do not often state superheater area separately; the one example that does state a value (613 sq ft) refers to the class as built "after 6-1-1913". Given that the first production example emerged from Juniata in February 2014, the 721 sq ft value may reflect a prototype or a different method of measurement. Locobase adopts the 613 sq ft figure as it appears consistently in later PRR documents.

(The Locomotive Testing Plant report stated (p. 47) that although the E6s could not equal the K2sa Pacific in starting tractive effort, "that it can produce a drawbar pull equivalent to that of the K2sa at speeds above 22 mph [35 kph] is significant of what has been accomplished with the Atlantic type.)

Locobase's tender data appears as the baseline 70 P 66 tender variant in the 1925 Classification and Description. Chris Hohl's email reported a variety of tender weights and Locobase's review of the tender information in the 1925 document determined that all E6s tenders were classed as 70 P 66. The tender section shows seven 70 P 66 variants with water capacities ranging from 7,100-7,400 US gallons (26,874-28,009 litres) and coal weights from 26,900-34,350 lb (12,202-15,581 kg). Loaded weights were as low as 146,000 lb (70 P 66d - 7,200 gallons/29,200 lb (27,252 litres/13,245 kg) up to 169,150 lb (70 P 66f - 7,400 gallons, 26,900 lb coal).

Gladulich also notes that the E6 had three sets of equalizers - one a central longitudinal beam linking the front bogie and lead driving axle and one for each side's rear driver and trailing axles and KW trailing truck. The Atlantic had an "exceptionally smooth" ride and was much less punishing on the track.

Like most Pennsylvania engines, these locomotives were worked hard, but proved reliable and long-lived.

An account of the 1927 race between an E-6s and an airmail plane to bring newsreel footage of Lindberg's return to Washington, DC tells us what this design could do when pushed. See [] (viewed 27 Dec 2002).

James Alexander, Jr. notes that engine #460 hit 115 mph (185 kph) at some points. After recounting the smashing success of the railroad's run (achieved by processing the film on the train as it rocketed along), Alexander summarizes #460's achievement:

"The spirited locomotive had in fact set a number of records, overall and on various stretches. The entire trip of 224.6 miles (362 km) to Penn Station at an average speed of seventy-two miles per hour beat the previous record of the Coolidge inauguration newsreel run by more than 32 minutes. The three-hour, seven-minute run stood in contrast with the top passenger-train time on that route of five hours. The Special's average speed of 74 miles per hour [119 kph] over the 216 miles [348 km] of steam territory was the world+s record for such a distance and set a record for the Washington-to-Manhattan Transfer distance that was never beaten while steam ran on that busy corridor."

Virtually all E-6s survived to the late 1940s or early 1950s. Most bore numbers in the 2800 range.

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Class VE-1 / E-21 (Locobase 9479)

Data from Angus Sinclair (ed), Railway and Locomotive Engineering, January 1903, p. 19; and "New Power for the Vandalia Line", Railway Age, Volume 34 (7 November 1902), p 490. Works numbers were 25460-25463 in August 1902.

These were the first Atlantics for the Vandalia Line (whose corporate name at the time was the St Louis, Vandalia & Terre Haute Railroad) and were typical 4-4-2s of the time, except perhaps for the use of slide valves. The firebox wasn't huge in the round-top boiler.

The Vandalia Line , itself an amalgam of railroads principally including the Terre Haute & Indianapolis, was taken into the Pennsylvania system in 1917.

All four were sold to the ferro-knacker between September 1924 and September 1925.

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Class VE-2/E-22 (Locobase 4094)

Data from "Classification and Description of Locomotives and Tenders", Pennsylvania Railroad, No 109-H, p. 9 supplied by Allen Stanley from his extensive Rail Data Exchange collection. See also the table in Paul T Warner's article on Atlantics in the Railway & Locomotive Historical Society Bulletin #62 (1943, p 20); Works number was 29238 in December 1903.

Compared to most 4-4-2s, this design had a somewhat higher percentage of total weight on the drivers. It was the only Atlantic to operate on the TH&I. Within two years, the TH&I was absorbed by the Vandalia Line, an amalgam of railroads. In 1917, the Vandalia Line was taken into the Pennsylvania system.

Very little changed over the years. The engine was never superheated and its cylinders stil took their steam from balanced slide valves. At some point, the shops added some area to the firebox, raising its heating surface area from 177.1 sq ft 15,45 sq m) to 196 sq ft (18.21 sq m), most likely through installing arch tubes.