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..

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 is 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 a short term of service, being retired in 1912.

Class E1 (Locobase 3877)

Notice the big anthracite-burning firebox. Data from an article in Railroad Gazette (3 August 1900). Comments in an article on the E-2, which see (RG, 14 September 1900), comment on the "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, http://www.northeast.railfan.net/images/prr820s.jpg (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.

Class E2 (Locobase 3878)

Data from an article in Railroad Gazette (14 September 1900) and from PRR Steam Locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

The RG article reported that "new features had been introduced in the spring rigging [caused] the engine to ride very smoothly on tracs 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."

Class E28/E2B (Locobase 115)

Data from Bruce (1952). See also "Locomotive for Experiment, Pennsylvania Railroad," Railway Master Mechanic, Vol XXX, # 2 (February 1906), pp. 42-46. Works numbers were 25548 in April 1905, 25606 in May.

Unusual Pennsy locomotive in that it used compounding (balanced, 4-cylinder 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 and 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.

Class E29/E2B (Locobase 5382)

In the same year that the Pennsy bought 2 Baldwin balanced compounds, Alco delivered 2 Cole 4-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.

Data from table in the June 1907 issue AERJ. Later simpled, these were reclassified E2b along with the two Baldwins.

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 http://broadway.pennsyrr.com/Rail/Prr/Rosters/steam_class.html#class_e (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).

Class E2D (Locobase 8416)

Data from 1908 Annual Convention of the American Railway Master Mechanics Association (in Atlantic City), p. 301.

These Atlantics were virtually identical to the E2As supplied a few years earlier, but there were interesting differences. For one thing, the E2Ds had 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 away from the three carrying axles.

Class E2sd (Locobase 9483)

Data from Rob Schoenberg's scanned-in diagrams at http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=E2sd_E3sa_E3sd-E85286.gif&sel=ste&sz=sm&fr= (visited 5 February 2003) and PRR Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

As the Pennsy superheated its large stud of saturated Atlantics, it adopted a standard boiler for all of the earlier classes. As usual in North American superheater conversion projects, the boiler lost almost half of its 2" tubes in favor of 24 larger flues.

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.

Class E3A (Locobase 5329)

Data from http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=E2a_E3a-E85285.gif&sel=ste&sz=sm&fr= (visited 5 Feb 2003) and AERJ July 1903. The website http://broadway.pennsyrr.com/Rail/Prr/Rosters/steam_class.html#class_e (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.

Class E3sd/E4s/E5s (Locobase 452)

Data from Rob Schoenberg's scanned-in diagrams at http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=E2sd_E3sa_E3sd-E85286.gif&sel=ste&sz=sm&fr= (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.

Class E6s (Locobase 109)

These engines were a development of the earlier E3s. Chief Mechanical Engineer Axel Vogt wrung still more power out of the E3 design by enlarging the boiler diameter from 65 to 76 inches, adding a combustion chamber to the firebox, and installing a superheater. The piston load per pound of reciprocating parts was 83 lb, according to Railway Age (21 July 1916), which was 5.1% more than the Reading Pacifics.

Richard M. Gladulich summarizes the impact of the superheater in his Pennsylvania Railroad Museum (http://www.rrmuseumpa.org/about/roster/e6.htm, 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.

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 http://www.rrmuseumpa.org/membership/milepost/lindy/taletwomemos.htm (viewed 27 Dec 2002).

James Alexander, Jr. notes that engine #460 hit 115 mph 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 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 over the 216 miles 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.

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

Data from Angus Sinclair (ed), Railway and Locomotive Engineering, January 1903, p. 19.

These were the first Atlantics for the Vandalia Line and were typical 4-4-2s of the time, except perhaps for the use of slide valves.

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

Class VE-2 / E22 (Locobase 4094)

Taken from a table in Paul T Warner's article on Atlantics in the Railway & Locomotive Historical Society Bulletin #62 (1943, p 20). Compared to most 4-4-2s, this design had a somewhat higher percentage of total weight on the drivers. Additional data from table in AERJ July 1904

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