Class H10s (Locobase 1035)

Similar to H-9s, but with a 1" larger piston diameter (2" larger than the H-8s) and built for Lines West. All had Belpaire fireboxes. (See Locobase 32 for a comment on the unique design of Pennsy's Belpaire firebox.) Data from Railway Age comparative table 13 May 1921.

According to the 1928 locomotive diagram offered on Robert Schoenberg's site (http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=H10s-E85283.gif&sel=ste&sz=sm&fr=, Consulted Sept 2002), however, the heating-surface areas had changed and now matched those of the H9 and H8s. This is borne out by the table from a Pennsylvania Railroad 1956 summary of locomotives.

273 built in 1913-1916 for Lines West -- 95 by ALCO-Pittsburgh, 75 by Baldwin, 73 by ALCO-Brooks, and 40 by Lima. Many H-8, H-9 converted as well.

Class H28 (Locobase 5374)

Data from table in July 1906 AERJ. Clearly two representatives of New York Central thinking sneaking onto Pennsy property. These had the radial-stay boilers, long piston stroke, inside valves, and large grate of the NYC Consolidation.

Bob Berkey of http://broadway.pennsyrr.com/Rail/Prr/Rosters/steam_class.html#class_j notes that Pennsy's development of large-boiler 2-8-0s followed these two.

Class H4 (2 1/4"") (Locobase 2818)

Data from diagram scanned in by Robert Schoenberg of http://prr.railfan.net . H4 designation covers two slightly different boiler layouts -- this one with 2 1/4" flues and another of 376 tubes of 2" diameter.

Class H4 (2"") (Locobase 2817)

Data from diagram scanned in by Robert Schoenberg of http://prr.railfan.net . H4 designation covers two slightly different boiler layouts -- this one with 2" flues and another of fewer tubes of 2 1/4" diameter. Built for Lines West operation. http://www.northeast.railfan.net/prr_steam2.html

Class H5 (Locobase 2819)

Data from diagram scanned in by Robert Schoenberg of http://prr.railfan.net . Like all other Pennsy engines of this time (and later), this class had Belpaire boilers. According to McShane (1899), preliminary tests with the H-5s yielded drags of 578 tons light and 643 tons loaded. This eclipsed the Class Rs by more than 200 tons. But they were used primarily as pushers. See http://www.northeast.railfan.net/prr_steam2.html

Class H6a (Locobase 4795)

See Railway and Locomotive Historical Bulletin #124 for a full account of this the most numerous single class built by the Pennsy (or any other US railroad). As Richard D. Adams explains, the original H6 had a narrow firebox that proved balky to fire properly. Pennsylvania designers and the Baldwin works applied the wide firebox (Belpaire of course) introduced by the E1 and E2 Atlantics to the Consolidation and a star was born. Adams notes that the need on the road was so great that Baldwin produced 1,017 H6a locomotives from 1902-1905.

Further development, including the introduction of larger piston valves and Walschaerts valve gear, led to the H6b, which see. 154 H6a were later superheated with larger cylinders (23" x 28") and piston valves, but retained their Stephenson motion.

Class H6b (Locobase 1030)

See Railway and Locomotive Historical Bulletin #124 for a full account of this quite numerous class. Although like its H6a predecessors in the essential dimensions of its Belpaire boiler and firebox, the H6b had 12" piston valves and introduced Walschaerts valve gear. They were never fitted with automatic stokers.

All but 38 were later superheated as H6sb with a few being fitted with 23" x 28" cylinders. In this configuration, Adams reports, "they were one of the finest freight engines that the PRR ever owned ..."

Some data from Robert Schoenberg's equipment diagram collection http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=H6b-E85285.gif&sel=all&sz=sm&fr= (Consulted September 2002)

Class H6sa/H6sb (Locobase 5490)

Data from Robert Schoenberg's equipment diagram collection http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=H6sa-E80742.gif&sel=all&sz=sm&fr= (Consulted 11 April 2003)

Of the hundreds of H6a-class Consolidations built (Locobase 4795) 156 were later superheated as H6sa. The upgrade retained the Belpaire firebox and Stephenson link motion, but rearranged the boiler innards to accommodate the large superheater flues. The refit also replaced the slide valves with 12" piston valves. See Locobase 32 for a comment on the unique design of Pennsy's Belpaire firebox.

543 H6sb (Locobase 1030) that had been built with Walschaerts gear (and 4 H6a) received identical upgrades. Some of the 6sb kept their 22"-diameter cylinders (and the 205 psi boiler pressure) while others received the 23"-diameter cylinder and slightly lower, 195-psi rating.

Many 6sb remained in service until dieselization and were fitted with power reverse. According to Richard Adams in Railway and Locomotive Historical Bulletin #124, 117 still carried on in 1947. By 1954, however, only 2 were left.

Class H8a (Locobase 1032)

Hundreds of H-8s built in several slight variations, most of which were converted to superheating, reclassified as H-8sb (Locobase 5492) or H-9s (Locobase 1034). All used the by-now trademark Belpaire fireboxes.

25 H-8 (242,000 lb) by Juniata in 1907

117 H-8a (235,000 lb, 14" piston valves) for Lines West 1907-1911 -- 50 Baldwin, 55 Juniata, 12 ALCO-Pittsburgh

238 H-8b (240,700 lb, 12" piston valves) -- 158 Juniata, 80 Baldwin -- and 114 H-8sb (252,500 lb) -- all Juniata-built -- for Lines East in 1908-1913

160 H-8c (239,500 lb, designed for mechanical stokers) and 32 H-8sc (249,500 lb) for Lines West in 1910-1913

-- 115 ALCO-Brooks, 25 ALCO-Pittsburgh, 20 Juniata H-8c and 32 Juniata H-8sc

Class H8sa/H8sb (Locobase 5492)

Data from Robert Schoenberg's equipment diagram collection http://prr.railfan.net/diagrams/PRRdiagrams.html/Steam//sm_H8sb.gif (Consulted 11 April 2003)

Like the earlier H6 series, most H8's were delivered as saturated steamers -- like virtually all Pennsy engines, these had Belpaire boilers. Soon, many of them were superheated, apparently through the expedient of removing about half of the firetubes and replacing them with 5 1/2" flues. 35 H8a and 228 H8b were so converted, the H8as weighing less (219,500 lb on the drivers). Of the H8sb group, 143 were later fitted with 25" cylinders, thus being transformed into H9s.

Like the other superheated Consolidations, many of the H8 series kept working until the late 1940s.

Class H9as (Locobase 5477)

Data from Rob Schoenberg's prr.railfan.net/diagrams/PRRdiagrams.html treasury consulted 9 April 2003. Very similar to the H9s on the Pennsy, but with less superheater area. The first driving axle had a high loading compared to the other 3.

The Pittsburg, Cincinnati, Chicago and St. Louis Railroad Company was formed through the consolidation of the Chicago, St Louis & Pittsburgh; the Pittsburg, Cincinnati & St. Louis Railway Co., the Cincinnati & Richmond Railroad Co. (No. 2), and the Jeffersonville, Madison & Indianapolis Railroad Co on June 10, 1890. A later combination involved the Vandalia; Pittsburgh, Wheeling & Kentucky Railroad Co., the Anderson Belt Railway Co.; and Chicago, Indiana & Eastern Railway Co -- this agglomeration was confirmed on Sseptember 28, 1916. The Pennsylvania negotiated a 999-year lease of the line on March 26, 1921.

Class H9cs (Locobase 5482)

Data from Rob Schoenberg's prr.railfan.net/diagrams/PRRdiagrams.html treasury consulted 9 April 2003. The full name of this Pennsy subsidiary was Pittsburgh, Cincinnati, Chicago and St. Louis Railroad Company as of 1916, when it also incorporated the Vandalia and several others. The PRR leased the line for 999 years in 1921.

Rebuilds similar to the Pennsy's H9s, but with smaller superheaters. For some reason, these 11 did not have arch tubes. Berkey (http://broadway.pennsyrr.com/Rail/Prr/Rosters/steam_class.html#class_l -- 1 Feb 2004), says three were later converted to H-10s by installing 26" x 28" cylinders.

Class H9s (Locobase 1034)

Similar to H-8, but with a 1-in larger piston diameter; all had Belpaire firebox. See Locobase 32 for a comment on the unique design of Pennsy's Belpaire firebox.

274 built in 1913-1914 for Lines East -- 194 by Baldwin, 80 by Juniata. 279 H-8, H-8sb converted to H-9s as well.

18 H-9sa (237,200 lb) converted.

11 H-9sc (240,945 lb)

Data for the heating surfaces come from the Pennsylvania's 1956 summary of locomotives, as confirmed by several diagrams from Rob Schoenberg's PRR website.-- http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=H9s-45442_2.gif&sel=ste&sz=sm&fr= (visited 11 June 2004).

There are other figures, however. One of Schoenberg's scans was:

Class: H9s - 2-8-0 Steam Loco

Tracing#: 45442(B) (Other revisions available: (none) - 45442(A) - E45442 - E428887)

Although all the basic data seems the same (number of tubes & flues and their length, e.g.) as other diagrams and the numbers shown in the 1956 summary. But the superheater is credited with 782 sq ft, while the firebox area is 190 sq ft.

The 45442(A) drawing shows yet a different set of areas:

187 sq ft in the firebox, 1173.9 sq ft of superheater. Were these both experiments?

Class I/H1 (Locobase 1141)

Most of the data comes from diagram scanned in by Robert Schoenberg of http://prr.railfan.net . Class data from Bob Berkey's The Broad Way website. http://broadway.pennsyrr.com/Rail/Prr/Rosters/steam_class.html#class_j (visited 16 Feb 2003).

One of the classes established by Alexander J. Cassatt in 1867 when he became Master of Machinery. In fact, it is this class that is credited with re-invigorating the 2-8-0 layout after a very slow acceptance rate following its introduction on the Lehigh Valley (Locobase ).

John White (1968) reported that after its 1876 adoption, the new I class regularly moved trains of 80-90 cars at 14 mph.

A chronology of 1875 events put up in February 2006 -- http://64.233.161.104/search?q=cache:IOfRgoFtrK0J:www.prrths.com/Hagley/PRR1875%2520Feb%252006.pdf+pennsylvania+railroad+H1&hl=en&gl=us&ct=clnk&cd=9&client=safari, accessed 2 June 2006, notes that the type were also called "Modocs" after the Modoc Indians for their hauling power. They had a steel boiler barrel and "....firebox sloping to the rear with the space between the roof sheet and crown sheet filled with water, called the "Altoona boiler"; possibly influenced by Isaac Dripps's firebox on Camden & Amboy Crampton locomotives in late 1840s; "Altoona boiler" possibly influences Collin's adoption of Belpaire firebox 10 years later. (RyW, Warner, PRRTHS)"

Richard Adams's article on the Belpaire boiler on the Pennsylvania, hosted on the http://www.prrths.com/PRR_Belpaire.html, last accessed 2 June 2006, gives more detail on the "sloping firebox": "...top front of the firebox was 9 1/2" lower than the top of the boiler barrel and the sloped steeply to the rear. The space between the roof sheet and the crown sheet, which were flat and had the same slope, was filled with water. This type of construction became so closely identified with the PRR that is was officially known as the "Altoona Boiler". Its mechanical appeal was that it had the roof and crown sheets on the same plane, which meant they could be tied together effectively with stay bolts."

Adams comments on the limitations of the design as well: "Although experts claimed the sloping firebox had superior steaming qualities, there was a problem of fluctuating water levels in the sight glass while the engine was being worked. The reduction in water space made it difficult to carry water at the proper level. Generally, engineers carried their water higher than necessary. Despite problems, the boiler and sloping firebox remained on PRR freight locomotives until 1885."

57 of this class were later converted to Class B5 0-6-0s. See also Locobase 2453 for the Frisco entry covering some pass-alongs.

Class R (GR&I) (Locobase 3177)

Data from diagram scanned in by Robert Schoenberg of http://prr.railfan.net .

Class R/H3 (Locobase 1150)

Data from diagram scanned in by Robert Schoenberg of http://prr.railfan.net . Replaced I class. Freight traffic or heavy freight trains. Also represented the first use of a Belpaire boiler on a Pennsy locomotive. Tonnage rating on the Pittsburgh division was 350 tons light, 383 tons loaded.

Class R/H3A (Locobase 2816)

Data from diagram scanned in by Robert Schoenberg of http://prr.railfan.net . Later R class with smaller boiler, longer boiler tubes, more weight on the drivers; all had Belpaire fireboxes. Note on the diagram notes that this is the R class "built after 12/31/89." Building dates (1890-1893) confirmed by Class data from Bob Berkey's The Broad Way website. http://broadway.pennsyrr.com/Rail/Prr/Rosters/steam_class.html#class_j (visited 16 Feb 2003).

Class S/H2 (Locobase 1151)

Data from diagram scanned in by Robert Schoenberg of http://prr.railfan.net . http://www.northeast.railfan.net/prr_steam2.html

Replaced I class. Virtually identical to R, but lower axle load. Note the high boiler demand factor. 105 additional engines were delivered as H2a.