Western Maryland 4-6-2 "Pacific" Locomotives in the USA

Class K-1 (Locobase 1413)

Data from WM 1 - 1936 Locomotive Diagrams 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 41, p. 313; see below for John Bohon's comments on the K-1s (or "one fifties" as they were called). (Thanks to Chris Hohl for his 20 April 2015 email and spreadsheet noting the differences such as tender capacities between batches.) Works numbers 33382-33386 in April 1909; 36582-36586 in May 1911

The first Pacifics on the Western Maryland, these small locomotives had modest dimensions, drivers scaled to a mountainous profile, saturated boilers, and slide valves. The firebox heating surface area as delivered offered 164.2 sq ft (15.25 sq m) of heating surface area; 30.8 sq ft (2.85 sq m) of arch tubes was added later.

151-155 were delivered with working pressure set to 185 psi; 156-160 were set to 200 psi. The first five trailed tenders with 6,000 US gallon (22,710 litre) tenders that weighed 120,000 lb (54,431 kg); the last five increased capacity to the 7,000 gallons shown in the specs. As delivered, the tenders weighed 130,000 lb (58,967 kg) loaded.

The railroad they served included 3% grades, curves as tight as 20 degrees, and rails weighing between 86-90 lb/yard (43-45 kg/metre). They served the WM until 1943, when they were sold to the Seaboard Air Line as their class P-4 (road #871-880).

For Locobase, they also represent an opportunity to celebrate the willingness of correspondents like John Bohon to relay his much more direct experience with a locomotive class to a wider audience. John noted Locobase's comment in his K-2 entry (Locobase 175) and took issue with it, writing:

"Contrary to what is stated the WM did not find the K-1 too small or slippery. In fact the opposite was very true. Men from the era considered these little pacifics fine locomotives. The only complaint I ever heard was they were a little more precise to fire than the newer K-2. Many of the oldtimers considered the K-1, or hundred and fifties as they called them, the best looking locomotives the railroad ever owned. I include myself in those who think that way."

Duly noted, John, and thank you. Locobase's comment was based on the 32-ton disparity in adhesion weights between the two classes and the relatively low factor of adhesion in the WM specs.

John Bohon continues with some prize-worthy information on how these engines were used:

" The K-1's were built to replace older, smaller power on the existing passenger trains of the time. They were very well suited to handling these trains as well as the excursion trains the railroad often ran. As the years wore into the thirties and the many train offs came the K-1 found less and less work. Some were stored during the depression. During their last years on the railroad they worked occasionally in local freight service. Even in this service they reportedly did a good job."

In later years, the K-1s were superheated and the balance of tubes and flues stood at 137 2 1/4" tubes and 26 5 1/2" flues. The Seaboard Air Line bought all ten locomotives in 1943, most likely to remedy a passenger power shortage; they were grouped as class P-4. They saw out steam on the latter railroad as they retired between June 1950 and August 1952. In March 1946, one of the engines was sold to the Macon, Dublin & Savannah, retaining its road number 875. A month later, the 874 (ex-156) went to the SAL's subsidiary Tavares & Gulf ("Tug & Grunt") in Florida.

Class K-1 - superheated (Locobase 16165)

Data from SAL 1 - 1948 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Locobase 1413's comments section features John Bohon's extensive discussion of the K-1's considerable merits.

Locobase 1413 describes the K-1 class as it arrived on the WM in 1909 from Baldwin. At some later date, the railroad sacrificed almost half the tubes in the boiler to allow installation of a sizable superheater assembly that improved fuel and water economy. Like the majority of US Pacifics, the boiler now held both tubes and flues of the largest diameter. The firebox now had thermic syphons and cylinder volume grew when the cylinders were bored out to 23".

Two of the class received new boilers produced under Extra Work Orders at Baldwin's Eddystone plant. XO5940 covered 159's replacement in July 1922 and XO9837 did the same for 151 in February 1923.

The Seaboard Air Line bought all ten locomotives in 1943, most likely to remedy a wartime passenger power shortage; they were grouped as class P-4 and renumbered 871-880. They saw out steam on the latter railroad as they retired between June 1950 and August 1952. In March 1946, one of the engines was sold to the Macon, Dublin & Savannah, retaining its road number 875. A month later, the 874 (ex-156) went to the SAL's subsidiary Tavares & Gulf ("Tug & Grunt") in Florida.

NB: The SAL did not give superheater areas in their diagrams and the WM books don't show the superheated version of the K-1. The area in the specs is an estimate based on other Pacifics with identical superheater layouts within a narrow range of flue lengths.

Class K-2 (Locobase 175)

Data from tables in the 1930 Locomotive Cyclopedia, supplemented by WM 1 - 1936 Locomotive Diagrams 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 41, p. 322. (Thanks to Chris Hohl for his 20 April 2015 email and spreadsheet noting differences from the earlier K-1s and the original tender fuel (coal) and weight.) His 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error.) Works numbers were 38075-38078 in July 1912 and 38115-38119 in August.

These engines were considerably larger than the K-1s (Locobase 1413) that immediately preceded them. Baldwin and the WMd wanted more power and a higher factor of adhesion for a new express service (see below). Consequently, this design added a full 19 adhesive tons (17.2 metric tons) to the same wheel arrangement. (NB: Wes Barris's steamlocomotive.com received John Bohon's strong dissent from Locobase's original assessment of the K-1s as "too small and undersized". See 1413 for an amended appreciation of the "one hundred fifties").

The newer K-2s ushered in superheating. The Baldwin specs state not only that the parts were to be fitted to gauges and templates and thus be as interchangeable as possible within the class but also that the parts "are to be made interchangeable with Consolidation Locomotives built by American Loco. Co." These H-8 class 2-8-0s appear in Locobase 1412.

The cylinder diameters were enlarged by two inches (50.8 mm) and the superheated steam required a change from slide valves to sizable 14" (356 mm) piston valves. All were delivered with Baker-Pilliod gear, but were later changed over to Walschaert; a 1 February 1938 letter from the Office of Superintendent Motive Power to Baldwin confirmed that the last of the class had been converted. K-2s were delivered with boiler pressures set to 185 psi (12.75 bar), a common reaction to the introduction of superheaters in their first few years of use. Some had only arch tubes and a firebox heating surface of 234 sq ft (21.75 sq m); the 307 sq ft includes thermic syphons.

(A tidbit from the specs: Many locomotives of this era had frames and other structural members made of vanadium steel. Locobase hadn't previously seen a requirement that "bell metal to have vanadium content." He wonders if it changed the pitch or tone?)

For most of their career, the K-2s burned coal, but in 1947, four were converted to oil-burning and trailed tenders carrying 3,174 US gallons (12,014 litres) of oil and weighing 166,300 lb (76,433 kg).

Equally valuable to Locobase as the K-1 correction presented in Locobase 1413 is John Bohon's assessment of the K-2. As he granted us permission to use as much or as little as we saw fit, Locobase reproduces his comments in full:

"Like nearly all of the locomotives purchased from 1912 on the K-2's locomotives were a direct result of the opening of the Connellsville extension in 1912. This allowed the railroad access to the west and what eventually came to be called the Alphabet route. The K-2's went to work handling the new thru trains between Baltimore and Chicago including the first class Chicago and Baltimore Limiteds. Even with running times comparable to the B&O trains these new trains never went over all that well.

"The first class trains were gone by 1917 and from that time forward the railroad ran coach class trains. The K-2's found plenty of work in this service until most of the last of the trains were finally canceled in the early fifties and the few left were being handled with diesels.

"Like the K-1, the K-2 was very well liked by everyone I ever knew. They ran and fired easily and were powerful for their size. As stated four were converted to oil in 1947 to comply with smoke regulations in Baltimore, MD. these were 201, 202, 204, and 206. These four stayed east of Cumberland, MD after conversion to oil.

"Two of the K-2's, 204 and 205, were selected for further duty as boilers providing steam used to thaw coal in hoppers before they were unloaded into ships at Port Covington, the WM port in Baltimore. The 205 was converted to thaw service and sent to Baltimore but so far I have not been able to find evidence it was ever used. At least a couple of pictures show 205 in Baltimore and so converted. 205 was probably scrapped in 1955 or 1956. The 204 was indeed used used as a thaw engine. There are photos of it in that service. The 204 lasted until about 1961 and was almost a complete locomotive. For WM fans this is the locomotive that truly got away. Located only a few miles from the B&O Museum so late it appears the railroad gave no thought to saving the 204 and simply scrapped it. What makes this even more interesting is that until retirement the 204 was considered by many on the railroad including management to be the belle of the road.

"One K-2 class pacific did survive as one of two existing WM steam locmotives, the other being Shay WM 6. Oil burner 202 sits to this day on display in the city park in Hagerstown, MD. Until Chessie took over the WM, the railroad took very good care of 202. They painted it nearly every year. Around 1981 and after the railroad no longer cared for the locomotive the city sold the engine to an individual named John Long. We undertook a long restoration and may have even fired it up at least once. Since that time 202 has had a shed built over it and is lovingly cared for by by a group of fans. When Mr. Long passed away titile to 202 reverted back to the City of Hagerstown. Every park engine should be so lucky."

They saw out steam on the railroad, being retired in 1952-1954.