Class 1/ 3685 (Locobase 12028)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 17, p. 252. See also "Compound Consolidation Locomotive for the Cornwall & Lebanon Railroad", Railroad Gazette, Volume 24, No (17 June 1892), p. 441. Works number was 12632 in April 1892.

This Vauclain compound Consolidation was described by the Railroad Gazette as "one of the largest, if not the largest, compound locomotive yet built". The two cylinders on each side were mounted outside of the smokebox with the larger, LP cylinder over the smaller, HP cylinder. Each pair was supplied steam through a single 10 1/2" (267 mm) diameter piston valve.

Of course, by the time of the 2's delivery eight years later, it was no longer among the largest of compound locomotives. The only significant change was an increase in the tender's water capacity from 3,600 US gallons (13,625 litres) through widening the tank was widened by 18" (457 mm).

Apparently not converted to simple-expansion during their career, both served the C & L until that short line was absorbed by the Pennsylvania in 1918. The 3686 was sold for scrap in short order to Michlovitz in February 1922 while the 3865 evaded the ferro-knacker's torch until it was sold to J Caplan for scrapping in July 1923.

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Class 110 (Locobase 8458)

Data from DeGolyer, Volume 15, p. 254. Works number is 9739-9740 in January 1889.

(Note: Official name for the Cotton Belt was St. Louis-Southwestern.)

This pair of Consolidations was delivered to the WNY&P Railroad, a railroad incorporated in 1887 as a result of the organization of the Buffalo, New York & Philadelphia. The design was a relatively large and powerful 2-8-0 when delivered.

(The WNY&P Railway emerged from the railroad's bankruptcy in 1895 and was leased by the Pennsylvania in 1900.)

After a renumbering to 158-159, the two 2-8-0s went to the Pennsylvania in 1902 as 6284-6285.

The PRR sold both to locomotive rebuilder/reseller Southern Iron & Equipment in May 1908. SI&E sold the ex-6284 to the Pittsburgh, Somerset & Westmoreland of Ligonier, PA as their #6. Ex-6285 went to the Saint Louis-Southwestern (aka the Cotton Belt) in 1908.

This latter engine didn't stay on the Cotton Belt for long, moving to the Blytheville, Leachville & Arkansas Southern in December 1910; see Locobase 16069 for the 7's career and new boiler..

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Class 14 (Locobase 11689)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 16, p. 16. Works number was 10801 in April 1890.

This relatively hefty Consolidation served the C & L for almost 30 years before that railroad was taken over by the Pennsylvania and renumbered 3690. Never given a class ID, the engine was soon scrapped.

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Class 163/H odd (Locobase 11648)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 15, p. 232. Works numbers were 10567-10568, 10575, 10597, 10608, 10610 in January 1890.

Although its evaporative heating surface fell in the upper half of Consolidations built in that period, this class's firebox and grate were quite small for the time.

When the PRR bought the WNY & P in 1902, it took the class and put them in H odd along with several other orphan 2-8-0s. All had been sold to Southern Iron & Equipment by 1913.

6291 found a buyer early as it traveled to Cimmaron, Colo August 1907 to operate on the Cimmaron & Northern as the road's #1.

6289 went to the Gilmore & Pittsburg of Armstead, Idaho in September 1909 as their #13. Scrapping came in December 1920.

6294 stay at SI&E ended in July 1912 when the Cornie Valley of Wesson, Ark bought the engine and gave it number 9. The road was dismantled in 1928 and presumably the 9 was scrapped.

6293 ventured north to Massachusetts in September 1912 to operate as #15 on the Hoosac Tunnel & Wilmington.

6292 languished for six years at SI&E before the reseller found a buyer May 1913 in the Tennessee Railway as their #23. Logger Sabine Tramway bought the 23 in 1917 when the TRR folded and owned it until its scrapping in 1931.

6290's stay at SI&E lasted until September 1913 when she was bought by Louisiana Saw Mill of Alexandria, La.

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Class 169/H odd (Locobase 16215)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 17, p. 49. Works numbers were 11990, 11992-11993, 11997, 11999 in June 1891; and 12008 in July 1891.

This sextet was an only slightly different design from the 1890 locomotives shown in Locobase 11648, but it included cylinders with two-inch (50.8 mm) longer strokes and a wider, shallower firebox.

Locobase 11994 shows the original Vauclain compound built as a variant of this class. Before too long, it too emerged as a simple-expansion sister to the other six. In 1902, the Pennsylvania absorbed the WNY&P and placed thes engines in the H odd class as 6294-6301.

In October 1911, the Pennsy sold the 6301 to locomotive recycler/reseller Southern Iron & Equipment, which sold it on 28 April 1913 to the Atlantic & Western of Sanford, NC as their #6. The A & W ran it until the early 1920s.

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Class 175 (Locobase 11994)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 17, p. 97. works number was 12031 in July 1891.

A variant of the Consolidations that were delivered to the WNY&P at the same time (Locobase 16215), this Vauclain compound had relatively large 10 1/2" (267 mm) piston valves that jointly served both the HP and LP cylinders. Before long, the 175 was rebuilt with 19" x 26" cylinders; see Locobase 16215.

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Class 176/H odd (Locobase 6631)

Data from 1919 MD&G [Memphis, Dallas & Gulf] locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 22, p. 184. Works numbers were 17119-17122 in October 1899.

These were the last Consolidations built for the WNY&P and showed a signficant rise in tractive effort from the earlier engines shown in Locobases 11648, 16215, and 11994. This was particularly due to the substantial increase in boiler pressure as well as a slightly larger boiler. Otherwise, the locomotives didn't represent ground-breaking changes.

After their takeover by the Pennsylvania and subsequent exile to Class H odd, the four were sold to locomotive rebuilder/reseller Southern Iron & Equipment. 6302 was sold in December 1909 to the Tennessee Central as their 23. Soon renumbered 23 and again to 330. A little more than a year later, SI&E sold 6304 to the TC in March 1911 and took first 31 then 331. 331 suffered a boiler explosion in May 1942 and was scrapped a month later.

6303 went first to the Tennessee Railway in February 1910 and took road 22. The TRR sold it back to SI&E in , SI&E bored the cylinders out to 20", then sold it to the TC as their 32/332.

6305 took an entirely different path when the SI&E sold it in September 1911 to Louisiana Railway & Navigation as their 88. Successor Louisiana & Arkansas kept #88 until its scrapping in March 1934.

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Class 27/H61a, H61 (Locobase 16492)

Data from NC&StL 9 - 1921 Locomotive Diagrams-CLR CHTS supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 14, p. 78. Works numbers were 8999-9000 in January 1888.

Locobase plays a hunch with this entry when he uses the firebox area from the Birmingham Southern #9 described in Locobase 6868. He checked both Baldwin specifications and found the firebox dimensions (length, width, and both front and back heights) matched to the 1/8 ", the boiler tube diameters, counts, and tube length also were identical. Only the rail gauge differed. Baldwin used templates widely and this order seems to have adopted the specs of the BS locomotive.

Like the BS engine, this pair served two railroads. The CA&C renumbered 27 as 976 in 1901 and later as 947. The 28 may have taken #35, but certainly was renumbered 975 and later 998. All was resolved when the Pennsylvania bought the CA&C in 1911, gave the two engines consecutive road numbers and placed the pair in its own class H61a. In 1915, each road number gained a leading 1.

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Class 37/H odd (Locobase 12017)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 17, p. 194. Works numbers were 12436-12440, 12445-12447, 12460 in January 1892; 12496, 12464 in February.

Part of the rush of Vauclain compound orders, these ten engines were typical Consolidations as fitted with the system that featured HP and LP cylinders on each side driving on common crossheads and fed by 10 1/2" diameter piston valves.

Within months of the P&NW's absorption by the Pennsy, the class was converted to simple expansion using two 20" x 24" cylinders. Given their small size, however, it isn't difficult to understand why the Pennsy would scrap the class entirely in 1912 (2) and 1913 (8).

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Class 39 (Locobase 9155)

Data from Clinch 1943ca Locomotive Diagrams book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 11, p.65. Baldwin works numbers were 6698, 6701, 6709, 6713 in April 1883, 6765 in May.

The BNY & P's Consolidations featured a firebox with corrugated sidewalls (for strength, presumably, because the corrugations were only 1/4" deep).

The Western New York Railroad Archive ([], last accessed 14 February 2012) offers a tidy summary of the explosive expansion of this road after the board renamed the Buffalo & Washington in April 1871: "During its explosive growth by acquisition phase, the BNY&P purchased the Olean, Bradford & Warren Railroad, the McKean & Buffalo Railroad, 16,000 acres of land, and the 121 mile main line of the Western New York & Pennsylvania Railway in Pennsylvania. During 1883 the BNY&P purchased the Kendall & Eldred Railroad, The Buffalo, Pittsburgh and Western Railroad Company, The Olean and Salamanca Railroad Company, Bradford Railroad, Kinzua Railroad, Genesee Valley Canal Railroad, The Oil City and Chicago Railroad Company, and the Rochester, New York & Pennsylvania Railroad."

When the Buffalo was absorbed by the Western New York & Pennsylvania in 1887, the class retained its numbers until 1890, when they received 153-157.

The Pennsylvania Railroad gained control in 1902 and placed the 5 in its H odd class (for "odd" think "assorted"), but didn't keep them for long before selling them to locomotive rebuilder/reseller Southern Iron & Equipment. 6280 went in April 1903, 6279 in February 1905, 6281 and 6283 in May 1906, 6282 in May 1908.

SI&E sold 3 of the quintet to Virginia's South & Western Railroad. Ex-6279 took road number 35, 6281 wore 37, and 6283 was renumbered 36. The S & W was acquired by the Carolina, Clinchfield in 1908 and the trio now comprised class H-2. Clinchfield scrapped the 35 in July 1916, the 36 in October 1916, and the 37 almost a decade later in May 1925.

Ex-6280 served the Danville & Western for a few years before that Southern Railway affiliate sold it to locomotive rebuilder/reseller Georgia Car & Locomotive. GC&L found a buyer in Caryville, Florida's Henderson-Waite Lumber Company, which gave the engine road number 10.

Ex-6282 had a shorter second career after its sale to the Bentley Lumber Company of Brantley, Ala. Renamed the Ida Williams, the locomotive's later history is lost after the lumber company closed in 1913.

NB: The tube counts, diameters, and lengths are given as delivered in 1883, the heating surface area (which includes the firebox) was found in the 1943a Locomotive Diagram book.

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Class 80 / H6a/H6sa (Locobase 11548)

Data from Baldwin Locomotive Works Specification for Engines, 1903, as digitized by the DeGolyer Library of Southern Methodist University Vol 26, p. 37. Works numbers were 22774, 22839, 22844 in September 1903; 22923-22924, 22929-22930, 22963 in October; 23123-23124 in November. See also [] (last accessed 3 August 2010).

The CV was one of the oldest operating railroads in the United States when it ordered this decade of Consolidations. In 1859, the Pennsylvania bought a controlling interest in the profitable western Maryland line and from that time, the CVRR's motive power design took its cues from the much bigger road. These 2-8-0s were duplicates of the H6 engines (Locobase 4795) going into widespread service on the PRR at the same time.

When the Pennsy finally took over the CV in 1919, these locomotives were dropped into the H6 class and renumbered. Most were superheated (Locobase 5490), but all were scrapped in the late 1920s and early 1930s.

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Class 92 / H-3b (Locobase 12437)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 23, p. 78. Works numbers were 18034-18035 in August 1900.

Relatively small Consolidations with wider fireboxes than heretofore and based entirely on the large class of H3a delivered to the Pennsy beginning 1890; see Locobase 2816.

The Pennsy took them over in 1903 and renumbered them twice. But the Standard Railroad of the World apparently had no interest in keeping them and scrapped them in March 1915 (3284) and December 1916 (3279).

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Class GH-2/H-32 (Locobase 3177)

Data from diagram scanned in by Robert Schoenberg of [] . Works numbers were 12682-12687, 12694-12696, 12711-12717 in May 1892.

This was a subset of Pennsylvania's numerous R class of Consolidations (Locobase 1150) that was built for the quasi-independent GR&I.

Except for the 39, 42, and 44 (ex 304, 307, 309), which were retired before 1917, this class was given related ID H-33 when the GR&I's motive power was assigned Pennsylvania Railroad numbers. 09633 was cut up in 1920, the others sold for scrap between February 1923 and July 1924.

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Class GH-3/H-33 (Locobase 12031)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 17, p. 262 and Volume 18, p. 166. Works number was 12682-12687, 12694-12696, 12711-12717 in May 1892 and 13232-13233 in February 1893.

Light Consolidations of the late 19th Century that followed typical design practice including a radial-stay boiler.

Acquired by the Pennsylvania Railroad in 1920, they were quickly replaced and sold for scrap in 1923-1924.

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Class GH4/H34 (Locobase 11463)

Data from "Locomotive Building," The Railroad Gazette, Vol XXXVIII, No 15 (14 April 1905), p 119. Works numbers were 38596-38605 in December 1905.

These apparently were designed to conform to Pennsylvania Railroad standards, at least as far as the Belpaire boiler was concerned. Perhaps a list of equipment suppliers may illuminate:

Westinghouse American air brakes

Pennsylvania Railroad specification axles and journal bearings

"Little Giant" bell ringers

Keasby and Mattison magnesia boiler lagging

National hollow brake beams

American Steel Foundry's brake shoes and wheel centers

Kelso couplers

Star headlights

Nathan and Sellers' injectors

United States and Jerome piston and valve rod packings

Kunnle safety valves

Leach sanding devices

Nathan sight-feed lubricators

Union Spring Company's springs

Crosby steam gages

Latrobe driving and truck wheel tires.

NB: The direct heating surface (firebox) is an estimate based on calculating the tube surface area and subtracting it from the given total evaporative heating surface.

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Class GH4/H34a (Locobase 11422)

Data from "Locomotive Building," The Railroad Gazette, Vol XLIII, No 11 (13 September 1907), p 307. Works numbers were 44852-44855 in March 1908.

See Locobase 9513 for details on this Michigan railroad's beginnings and expansion. When the GR&I bought this quartet of Consolidations, it had just seen its peak passenger volume in 1907. All were renumbered in 1910, superheated in 1915-1918 and redesignated H34s

In 1918, the Pennsylvania bought the GR&I and these engines went with the deal. They were renumbered in 1920 and served a few more years before being scrapped between April 1925 (9603) and September 1926 (9602).

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Class H10s (Locobase 1035)

Data from 1928 locomotive diagram offered on Robert Schoenberg's site ([], Consulted September 2002). See also Baldwin's specification in the DeGolyer Library collection, Volume 49, pp. 292+ and Volume 51, pp. 161+.

Similar to H9s (Locobase 1034) with identical heating surface and grate areas, but with a 1" larger piston diameter (2" larger than the H8s) and built for Lines West. All had Belpaire fireboxes. (See Locobase 32 for a comment on the unique design of Pennsy's Belpaire firebox.) In addition, piston valve diameter increased from 12" (305 mm) to 14" (356 mm), but that was soon reduced to the 12" found in the H9s.

Baldwin's 1915 spec explicitly states (supplement 27) "Arch tubes not required. Not necessary to arrange staybolts to provide for arch tubes." The spec gave the firebox heating surface area as 175 sq ft (16.26 sq m), but by 1925, the area quoted had risen to 211 sq ft, which suggests to Locobase that 36 sq ft (3.44 sq m) of supplemental heating surface, possibly arch tubes, had been added.

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.

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Class H28/E-45 (Locobase 5374)

See also "Locomotive for Experiment, Pennsylvania Railroad," Railway Master Mechanic, Vol XXX, # 2 (February 1906), pp. 42-46. Works numbers were 32777 in August 1905 and 31246 in September.

Bob Berkey of [] notes that Pennsy's development of large-boiler 2-8-0s followed these two.

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.

7748 was retired by 1917, but 2762 was sold December 1916 to the Toronto, Hamilton, & Buffalo iin 1917 as their class G-1, road number 60. The TH&B sold the 60 in February 1920 to the Raleigh Lumber Company as their 60. Raleigh Lumber sold the 60 to the Cincinnati, Indianapolis & Western, which renumbered the engine 331. The CI&W was then absorbed by the Baltimore & Ohio.in 1927. At that point, the B&O renumbered the 331 as 439 and placed it in its own class E-45, operated it for about six years and retired it in 1933.

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Class H2a (Locobase 16436)

Data from PRR 3 109-D 1904 Class and Description of Locomotives supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection.

The significant difference between the H2 Consolidations shown in Locobase 1151 and built in the same years and the H2a was the crown-bar firebox fitted in the latter. Other changes included the addition of ten boiler tubes that increased heating surface area by 76 sq ft (7.06 sq m) and lower weight. Like the H2s, these were all intended for the Lines West railroads

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Class H34s, H34as (Locobase 16440)

Data from PRR 11 - 1925 109-H Class and Description of Locomotives supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection.

The original design with saturated boiler appear in Locobases 11463 and 11422 as GR&I GH4 class engines. Updated with a superheater between July 1915 and July 1918 , the new locomotives retained their 11" (279 mm) piston valves and Belpaire firebox.

Taken into the Pennsylvania Lines West proper in September 1920, the H34 served a few more years before being sold for scrap between April 1925 and October 1926.

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

Data from diagram scanned in by Robert Schoenberg of [] . H4 designation covers two slightly different boiler layouts -- this one with 2 1/4" flues and another of 376 tubes of 2" diameter (Locobase 2817). All of the locomotives ran on the lines west of Pittsburgh. Although

NB: The direct heating surface (including the firebox heating surface) is an estimate calculated by subtracting the calculated tube heating surface from the reported total evaporative heating surface.

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Class H4 (2") (Locobase 2817)

Data from diagram scanned in by Robert Schoenberg of [] . Baldwin works numbers were 17045-17054 in September 1899; 17847-17848, 17869, 17891 in June 1900; 17905-17906, 17952, 17965, 17985 in July; 18014-18015, 18026, 18055-18058 in August; 18089-18091 in September.

H4 designation covers two slightly different boiler layouts -- this one with 2" flues and another of fewer tubes of 2 1/4" diameter (Locobase 2818). Built for Lines West operation. The Baldwins were delivered to PRR subsidiaries Pittsburgh, Fort Wayne & Chicago (21) and the the Cleveland & Pittsburgh (8).

The design also featured the increasingly common Belpaire firebox.

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Class H5 - large tubes (Locobase 2819)

Data from diagram scanned in by Robert Schoenberg of [] and PRR 3 - 1904 109-D Class and Description of Locomotives dated 1 March 1904 supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange.

Like all other Pennsy engines of this time (and later), this class had Belpaire boilers. According to McShane (1899), preliminary tests with the H5s 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 [] . The 1904 109-D shows that the H5 boiler came in two version. This entry shows the 2 1/4" tube layout; see Locobase 16240 for the 2" tube boiler. Locobase hasn't been able to determine if one boiler was exchanged for another or if the class was split into two groups.

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Class H5 - small tubes (Locobase 16240)

Data from diagram scanned in by Robert Schoenberg of [] and PRR 3 - 1904 109-D Class and Description of Locomotives dated 1 March 1904 supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange.

Like all other Pennsy engines of this time (and later), this class had Belpaire boilers. According to McShane (1899), preliminary tests with the H5s 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 [] . The 1904 109-D shows that the H5 boiler came in two version. This entry shows the 2" tube layout; see Locobase 2819 for the 2 1/4" tube boiler. Locobase hasn't been able to determine if one boiler was exchanged for another or if the class was split into two groups.

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Class H6 (Locobase 15816)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 17, p. 262 and Volume 18, p. 166. Works numbers were 16819 -16822 in June 1899; 16868-16884, 16919-16922 in July; 18186, 18190-18193, 18225, 18226-18227, 18252-18253 in September 1900; 18273-18274, 18295, 18306, 18335-18336 in October; 18372-18373, 18403-18405 in November; 18430, 18432-18433, 18464-18465, 18489-18490, 18498-18499 in December; 18538-18539, 18557-18558, 18605-18608, 18634, 18645 in January 1900.

This was the last Consolidation narrow-firebox design delivered to the Pennsylvania. Its Belpaire firebox had a flat grate and proved difficult to fire properly. Increasing its width by 65% led to the 1901 H6a, one of the few locomotive classes to have more than 1,000 engines; see Locomotive 4795.

The H6 did not enter a superheater upgrade program. Most were retired in the mid-1920s.

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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). See also Charles Whiting Baker, "What is the Heating Surface of a Steam Boiler? , Niagara Falls Meeting (June 1898), Transactions of the American Society of Mechanical Engineers, Volume 19, (New York: ASME, 1898), pp. 571-600; "Locomotive Testing Plant of the Pennsylvania at St Louis", Railroad Gazette, Volume XXXVII [37], No 6 (22 July 1904), pp. 182-184; "The Laboratory Test of a Modern Locomotive", Railway Age, Volume XXXIX [39], No 18 (8 May 1905), p. 714; and Lawford H Fry, A Study of the Locomotive Boiler (New York: Simmons-Boardman Publishing, 1924), pp. 25-26.

Richard D. Adams explains that the original H6 (Locobase 15816) 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. Adopting the new firebox included increasing the width from 40" (1,016 mm) to 65 7/8" (1,673 mm), a 65% increase.

Locobase frequently reports both the fire side and water side tube heating surface areas, usually commenting that the latter measure, which uses the external diameter of each tube, was the preferred method in Great Britain and North America. An equally confident assertion that the fire side should be used appeared frequently in Anglo-American journals, particularly around the turn into the 20th century. Locobase found the Pennsylvania's extensive list of test methods reproduced in the 22 July 1904 Railroad Gazette included measurements of both the water and fire sides of the tubes.

The various reports of the H-6a's efficiencies as tested at the Pennsylvania Railroad's Locomotive Testing Plant set up at the 1904 St Louis Exposition used the smaller, fire side area, which was favored by many Continental railways. In summarizing the results, a Railway Age commentator claimed "There is no doubt at all that the fire side is the proper use for measuring heating surface." In fact, "it should be standardized by the Master Mechanics' Association."

This echoed Charles Baker's June 1898 presentation and several comments, letters, and articles by F W Dean, later head of the ASME. The argument for the fire side looked to where the combustion heat could be transferred to the tubes. Only from the inside surface area, proponents contended, could heat evaporate water. Serve tubes, which had eight small fins inside to increase surface area, were held up as confirmation. One saw those fins only on the fire side, not on the water side where they would accomplish nothing.

Baker's argument failed to persuade a majority of engineers then or later. Locobase offers a couple of thoughts as to why below, but first cites Lawford Fry, barrister for the water side argument. Born in Quebec, trained in Great Britain, and employed by Baldwin in a wide variety of research and management positions, Fry succinctly put the case for the water side in 1924.

He offered two main reasons: 1) That's the way it's been done in the US and the British Isles for 30 years and more. By itself, the argument seems to reduce to "We've always done it that way and it would be a world of trouble to change it." But Fry added the assertion that such a change "should not be done without strong compensating advantages" for the fire side method. He then describes the usual fire side argument as noting that the heat needed to evaporate is "taken up from the flue gases by this surface", but characterizes it as "academic," given that the formula used to calculate heating surface area "uses the flue perimeter and not the flue surface." The water side is a better metric, he concluded, because the outside surface is the "same for all tubes of the same nominal outside diameter and is not affected by the thickness of the flue." Locobase believes the "formula" to be circular reasoning and the nominal diameter argument a dismissal without examination.

Baker and Dean's arguments may not fare any better. In his presentation, Baker acknowledged that his example relied on a "clean" plate to best demonstrate the relationship between the heat of the gas inside and the heat of the water out. But plates aren't always clean, and he concedes the relative harm of scale on the water side and soot and ash on the fire side. "It is nevertheless quite certain that a thin scale on boiler tubes does not interfere in any noticeable degree with the capacity or economy of a boiler, while the coating of the fire side of the tubes with a flocculent deposit of soot does certainly interfere in a marked degree with a boiler's steam-making capacity." He adds that soot and ash aren't that difficult to clean.

Baker and Dean's reliance on asserting a 50% difference in evaporation in favor of Serve tubes seems to overlook a key fact: Serve tubes' external diameters were nearly 50% greater than the typical 2" plain tube. Locobase wondered about the claim anyway, wondering how the additional heating surface area would even come into play to heat the tubes.

Ease of maintenance often played a role, at least in North America, in the acceptance of new ideas and equipment for the operating staff.

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 at Locobase 1030. 154 H6a were later superheated (Locobase 5490) with larger cylinders (23" x 28") and piston valves, but retained their Stephenson motion.

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Class H6b (Locobase 1030)

See Railway and Locomotive Historical Bulletin #124 for a full account of this quite numerous class. See also some data from Robert Schoenberg's equipment diagram collection [] Consulted September 2002), and James Kennedy, "The Walschaerts [sic] Valve Gear as Applied to Locomotives," Proceedings of the New York Railroad Club, at meeting held at Carnegie Hall, New York, September 21 1905, Volume 16, pp. 337-, especially A W Gibbs comments at 345-

Although like its H6a predecessors in the essential dimensions of its Belpaire boiler and firebox, the H6b had 12" (305 mm) piston valves and introduced Walschaerts valve gear. Gibbs told the New York Railroad Club that the Pennsylvania's use of the Walschaert gear began with the de Glehn compound 2512 (Locobase 5316). The railroad had already realized that larger locomotives with more than two driven axles began to negate the many positive qualities of the link motion.

"[S]pring rigging, brake shoes and other devices" filling the space and lengthening the eccentric rods (which would soon need to be either bent or connected to the valves by a series of links). Even more problematic was the "increasing size of axles" that together with the "greater throw of eccentrics" necessicated a larger sheave. The result was increasing opportunity for lateral play and "very rapid wear of the eccentrics." These "purely mechanical" difficulties were the principal reason for abandoning the Stephenson link.

Gibbs said he was impressed by the de Glehn compound's careful alignment of "all the working parts in one vertical plane". Instead of using rockers to actuate slide valves, however, the railway decided to "change to the piston valve offset to the limit of our clearances." Gibbs said that reports from the field were so positive as the "road people, without exception, plac[ed] high value on the accessibility of the gear. "

Gibbs continued with other benefits. Eliminating the link motion's inside eccentric rods "very much facilitates attention to the driving boxes and, for the same reason, it has been practicable to introduce strong bracing between the frames [to lessen] frame breakage."

The Pennsy never looked back and almost certainly proved mightily influential in the widespread use of Walschaert gear.

They were never fitted with automatic stokers.

All but 38 were later superheated as H6sb (Locobase 5490) 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 [] (Consulted September 2002)

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Class H6sa/H6sb (Locobase 5490)

Data from Robert Schoenberg's equipment diagram collection [] (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.

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Class H8a/H8b (Locobase 1032)

Data from series of diagrams scanned by Robert Schoenberg and archived on [], last accessed 5 January 2012.

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 and had boilers with the highest tube count ever deployed in a Pennsy engine.

25 H-8 (242,000 lb, 12"/305 mm piston valves) by Juniata in 1907

117 H-8a (235,000 lb, 14"/356 mm piston valves) for Lines West 1907-1911 -- 50 Baldwin, 55 Juniata, 12 ALCO-Pittsburgh

238 H-8b (240,700 lb, 12"/305 mm 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, 14"/356 mm piston valves, 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

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Class H8sa/H8sb (Locobase 5492)

Data from Robert Schoenberg's equipment diagram collection [] (Consulted 11 April 2003)

Like the earlier H6 series, most H8's were delivered as saturated steamers (Locobase 1032) -- 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.

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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.

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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 ([] -- 1 Feb 2004), says three were later converted to H-10s by installing 26" x 28" cylinders.

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Class H9s (Locobase 1034)

Data from several diagrams from Rob Schoenberg's PRR website.-- [] (visited 11 June 2004). See also DeGolyer, Volume 44, pp. 191+; and Volume 49, pp. 284+.

Similar to H-8, but with a 1" (25.4 mm) 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)

Three American Security Arch tubes contributed 22.6 sq ft (2.1 sq m) to the firebox heating surface area. Cylinders were supplied through 12" (305 mm) piston valves. As ordered from Baldwin, the design's superheater area was calculated as 623 sq ft (57.88 sq m) and total EHS at 3,048 sq ft (283.17 sq m).

One spec in Supplement 85 of the 11 September 1913 order contains four-letter words that ring oddly to the ear of the 21st century technologist: "Pack oil cup on Walschaert Valve Gear with hair instead of wool." No species of hair is specified.

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 (72.65 sq m), while the firebox area is 190 sq ft (17.65 sq m).

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

187 sq ft (17.37 sq m) in the firebox, 1173.9 sq ft (109.06 sq m) of superheater. Were these both experiments?

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Class I/H1 (Locobase 1141)

Most of the data comes from diagram scanned in by Robert Schoenberg of [] . Class data from Bob Berkey's The Broad Way website. [] (visited 16 Feb 2003). See also Baldwin Locomotive Works, International Exhibition 1876, Exhibit of Locomotives by Burnham Parry Williams & Co (Philadelphia: J P Lippincott & Co, 1876), pp. 14-16; and "Consolidation Locomotive, Class R, Pennsylvania Railroad", Railroad Gazette, (17 September 1886), pp 638-649, 644;

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 (22.5 km/h).

As with the Lehigh Valley exhibition piece described in Locobase 11179, an example of this locomotive displayed at the 1876 International Exhibition at Philadelphia (often known as the Centennial Exposition) listed many of the suppliers of components for the engine:

Boiler, Bay State Iron Co.'s Homogeneous Cast Steel [Boston, Mass];

Fire-Box, Singer, Nimick & Co.'s Homogeneous Cast Steel [Pittsburgh, Pa];

Tires, Standard Steel Works' Crucible Cast Steel [Philadelphia, Pa];

Truck-Wheels, A. Whitney & Sons' Double-plate Chilled Wheels [Philadelphia, Pa];

Flues, Morris, Tasker & Co.'s Lap-welded Charcoal Iron Boiler-Tubes [Philadelphia, Pa];

Injector, William Sellers & Co.[Philadelphia, Pa];

Steam-Gauge, H. Belfield & Co.[Philadelphia, Pa];

Headlight, Pennsylvania Railroad Co.;

Brass and Copper Piping, American Tube Works [Boston, Mass] ;

Jacket Iron, W. D. Wood & Co.'s Patent Planished Sheet Iron [Pittsburgh, Pa].

A chronology of 1875 events put up in February 2006 -- [], 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 [], 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.

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Class R/H3 (Locobase 1150)

Data from diagram scanned in by Robert Schoenberg of []; "Consolidation Locomotive, Class R, Pennsylvania Railroad", Railroad Gazette, (17 September 1886), pp 638-649, 644; and Alvin Staufer (text by Bert Pennypacker), Steam and Electric Locomotives of the Pennsylvania Railroad 1900-1957 (Alvin F Staufer, 1962), p. 33.

Replaced I class (Locobase 1141), which, RG reported, had the same wheelbases as the I class. That was about the only similarity because the new boiler measured 6" (152 mm) more in diameter, had a square firebox (i.e., the first of many Belpaire-type fireboxes on the Pennsy);greater area for both the firebox and grate, and 15 psi (1.03 bar) higher boiler pressure setting than the I class.

To raise the firsbox above the frame, the designers placed the springs of the main and third axles were set below the axles..Smokebox and stack differed radically from the I: "Low nozxles, a petticoat pipe, and a diamond stack have given place to high nozzles, extended front, and taper stack." All in all, the Rs matched up to any other Consolidation of the time, but in substantially graater numbers. Indeed, Bert Pennypacker later wrote the H-3s "served very successfully all over the railroad."

Tonnage rating on the Pittsburgh division was 350 tons light, 383 tons loaded. Pennypacker documented an H-3 263's April 1892 run from Chicago to Girard Point, Philadelphia that trailed 45 cars adding up to "around two thousand tons." Several steep grades required helpers "at several points east of Pittsburgh."

The official PRR Historical Society chronology reported: First through grain train of 40 Union Line cars (1,200 tons) with a Class R (H3a) locomotive leaves Chicago [on 30 April 1892] n route to Girard Point, Philadelphia; arrives May 3 without change of locomotive; average speed, 15 MPH [24 kph]. Pres. Roberts, in a long interview, states that an all-rail route can beat the

Lake-rail route for grain. (RyW, RRGaz)"

(April 1892 also witnessed another key benchmark: "PRR adopts carbon paper triplicate forms for shipping invoices".)

Many were upgraded to H3a; see Locobase 2816.

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Class R/H3a, 3b, 3c (Locobase 2816)

Data from diagram scanned in by Robert Schoenberg of [] . Later R class (see Locobase 1150 for the earlier Rs). Although given the same class ID, the later engines had 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. [] (visited 16 Feb 2003).

329 H3a, 143 H3b were built new. Also, many H3 (1150) were converted to H3a.

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Class S/H2 (Locobase 1151)

Data from PRR 3 109-D 1904 Class and Description of Locomotives supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection.

Replaced I class. Virtually identical to R, but lower axle load. Sent to subsidiaries in the Lines West region: Cincinnati & Muskingum (1); Cleveland & Pittsburgh (13): Erie & Pittsburgh (5); Little Miami; Pittsburgh, Cincinnati, Cleveland & St Louis (41); Indianapolis & Vincennes (3); Pittsburgh Ft.Wayne & Chicago (26); Toledo, Walhonding Valley & Ohio (3).

Note the Belpaire firebox and the high boiler demand factor. 105 additional engines were delivered as H2a with crown-bar fireboxes.