Class N-1/N-2/N-2a/N-4 (Locobase 144)

Data from set of DL&W locomotive diagrams at [] (29 October 2003) and DL&W 7 - 1927, DL&W 7 - 1933, and DL&W - 3 -1938 Locomotive diagram books supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (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 51348-51354, 53143-53145, 53158-53164 in 1912 and 54636-54639 in 1914.

Fourteen built with wide fireboxes for burning anthracite (this was Phoebe Snow's Road of Anthracite, after all). All had five 3"(76.2-mm) diameter arch tubes contributing 36 sq ft (3.25 sq m) of the firebox heating surface and all had 14" (356 mm) piston valves.

Note about valve diameter. Locobase has found that early in their careers, all DL&W Pacifics are shown with 14" valves (Cf. the 1927 Diagram books for the N through N-4, and 1915-1916 journal reports on the later classes.). But all of the succeeding books show 11" valves on the N-1 to N-4 classes, although the radial valve remains the Walschaert design.

But the last four somehow gained 17 sq ft (1.6 sq m) of heating surface on the same number and length of tubes. But not to worry.

The N-2a shown in the 1933 book had a cylinder stroke of 26" (660 mm), which reduced tractive effort to 39,842 lb.

Retired in 1940-1948.

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Class N-13 (Locobase 3752)

Data from DL&W locomotive diagrams at [] (29 October 2003). (Thanks to Chris Hohl for a 9 February 2018 email and spreadsheet noting the details of the N-13 conversions.) Works numbers were 65398-65407 in 1924.

These ten were the last of the Lackawanna's freight Pacifics. They were equipped with a modest list of modern appliances: Alco Power Reverse E, Security Brick Arch, Chambers Throttle, power grate shakers, B&S drifting valve. They were delivered with 12" (305 mm) piston valves.

Within ten years, six had already been converted to heavy 0-8-0 switchers: 1184-1188, 1190 were rebuilt between February and November 1933 and renumbered 231, 237, 234, 232, 236, and 235, respectively.

In 1943, the Boston & Maine bought the other four of the class, designating them P-5a and numbering them 3696-3699. In that livery and rolling on 62" (1,575 mm) drivers, they carried on until 1951-1952, when most B&M steam was retired.

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Class N-3 (Locobase 7582)

Data from reproduction of 1913 Alco Bulletin 1016 on Richard Leonard's [] (accessed 16 June 2006). See also "Pacific Type Locomotive for the Lackawanna," Railway and Locomotive Engineering, Vol , No 8 (August 1913), p. 286; and "Pacific Type Locomotives, Delaware, Lackawanna & Western RR" Railway and Engineering Review, Volume 53, No. 1 (5 July 1913), pp. 641-642. Works numbers were 53158-53164 in May 1913.

This septet of Pacifics was not used in passenger service, but rather as fast freight engines. The Lackawanna wanted much more power than their Moguls, even the E-11s shown in Locobase 14460), they chose the Pacific arrangement because of its substantial boiler capacity. They took the anthracite-burner 73" passenger Pacific and transformed into a soft-coal burning Pacific bearing an entirely new boiler design. The rest of the locomotives could easily share "almost all of the parts that require the most frequent renewals or need to be kept in stock.", said the R&LE report.

The importance of of a big boiler to the Lackawanna becomes clear when the R&LE notes that in the new design motive power system (engine and tender) weight increased by 50% and available tractive effort by 47.8%, but "equivalent" (evaporative heating surface area plus 1 1/2 times the superheater area) heating surface grew by 142%.

R&LE summarizes the degree of success in meeting the goal of reducing ton and car mile water and coal consumption by observing: "On a train mile basis these new big engines handle their increased train loads on practically the same coal and water consumption as the smaller Moguls."

When the DL&W ran short of heavy switchers in the last 1920s, it took the boilers of this class and put them on a new frame with an 0-8-0 layout. The tube and flue distribution remained the same after conversion to the C-9 class, but all were shortened by more than four feet. Also, the engines now put 258,000 lb on the drivers, a hefty increase.

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Class N-5 (Locobase 3094)

See DL&W locomotive diagrams at [] (29 October 2003). See also "Lackawanna Pacific Type Freight Engine", Railway Age, Volume. 57, No. 15 (9 October 1914), pp. 657-659. (Thanks to Chris Hohl for a 9 February 2018 email and spreadsheet noting the details of the N-5 conversions.) Works numbers were 1381-1393 in July 1914.

An early version of Lima Super Power -- note the adequate superheat ratio, combustion chamber, relatively short tubes. The latter reflects the inclusion of the combustion chamber. Unlike the Alco engines of a year earlier, however, these engines were later converted to C-10 0-8-0 switchers in 1928-1933 -- largely because their job as fast freight power was soon taken over by the large stud of 2-8-2s the Lackawanna acquired over the next ten years.

The last two were Schenectady-built in 1916. 1172 from this pair exploded on Lehigh Summit in July 1930.)

The 1914 article from RA shows a different set of heating surfaces. Evaporative heating surface was given 3558 sq ft, of which 279 was in the firebox (and 21 of that was arch tubes). Superheat is given as "about 1,000" sq ft, a lot larger than the diagrams show.

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Class N-5a (Locobase 5735)

Data from DL&W locomotive diagrams at [] (29 October 2003). See also "The Riegel Design of Locomotive Firebox," The Locomotive World, Vol 7, No 5 (May 1915), pp. 3-5. Works number was 1394 in August 1914.

This engine was fitted with a hybrid firebox designed by the Lackawanna's S S Riegel. According to the Locomotive World article, "The design ...comprehends a scheme for taking advantage of the water tube method of steam generation and water circulation, with the object of providing definite cycles of circulation of water over the heating surfaces and locating these surfaces in the best possible manner within the zones of greatest intensity of heat."

To accomplish this, Riegel put two "nests" of water tubes, 66 tubes each, that connected the lower sides of the firebox with the crown sheet. To picture the result, imagine rows of tubes forming an A as you look into the firebox. The fire would swirl around the tubes heating the water as it passed through. Similar in concept to the Nicholson thermic syphon that would soon be widely adopted, the Riegel required many more openings in the sides and tops of the firebox. A "considerably restricted" brick arch did serve to encourage the fire's circulation.

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Class N-6/N-6a (Locobase 6293)

See "Heavy Pacific Type Locomotive for the Lackawanna", Railway Age Gazette, Volume 59, No.26 (24 December 1915), pp.1185-1187 and Two Powerful 4-6-2 Locomotives", Railway Mechanical Engineer, Volume 90, No 1 (January 1916), pp. 4-5. (Thanks to Chris Hohl for his 9 February 2018 email pointing out several differences in the entire run of DL&W Pacifics. His specific comments appear below.)Works numbers were 55127-55131 in 1915 (road number order was 1132-1135, 1131))

According to RME, the class was intended for service on the mainline between Scranton and Hoboken. This line had a ruling grade of 78 ft to the mile (14.75 m/km) (ca. 1.4%) over a 16-mile (25.75 km) stretch and curves with radii of 5 and 6 deg. "The new engines," said the report, " are hauling trains of 9 steel cars, weighing 600 tons under the above conditions [30 mph on the ruling grade]." RAG's report claimed these were the "most powerful of this type on record at this time [late 1915]". Superheater area was originally calculated at 760 sq ft (70.6 sq m), but later diagrams show 808 sq ft.

Equipped with the anthracite-burning Wootten boiler and 14" (356 mm) piston valves, these locomotives allowed the elimination of helper service on all trains in the Mountain division of ten cars or less. One of the five was delivered with a Riegel firebox in which 38 watertubes connected each water leg with the crown. Later Delaware, Lackawanna & Pacific locomotives would have taller drivers, but none would be heavier.

Note about valve diameter. Locobase has found that early in their careers, all DL&W Pacifics are shown with 14" valves (Cf. the 1927 Diagram books for the N through N-4, and 1915-1916 journal reports on the later classes.). But all of the succeeding books show 11" valves on the N-1 to N-4 classes, although the radial valve gear remains the Walschaert design.

Chris Hohl notes that all five had their tenders' coal capacity increase to 15 tons (13.6 metric tons); they now weighed 175,800 lb (79,742 kg). Hohl also noted that in the late 1920s-early 1930s, all but the 1134 had their boiler pressures reset to 210 psi (14.5 bar), which increased calculated traffic effort to 49,912 lb (22,640 kg or 222 kN) and decreased the starting factor of adhesion to a still-adequate 3.95. The modified engines were then designated N-6a.

The last of this class retired in 1953.

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Class N-7, N-11 (Locobase 5736)

See DL&W locomotive diagrams at [] (29 October 2003) for this follow-on class to the Lima freight Pacifics of 1914 (Locobase 5735). (Thanks to Chris Hohl for a 9 February 2018 email and spreadsheet noting the details of the 0-8-0 conversions.) Works numbers were 55920-55926 in July 1916 and 63606-63610 in October 1922.

The 1922 group--N-11--had only two arch tubes instead of four, dropping this component's contribution to firebox heating surface from 21 to 14.6 sq ft.

All were converted into 0-8-0 heavy switchers in the late 1920s, the N-7s being placed in class C-11, the N-11s in C-12.

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Class N-8/N-9, 9a/N-10, 10a/N-12,12a (Locobase 3306)

One of the locomotives which Estimating Engineer for Alco, compared his company's #50000 in The Estimating Engineer for Alco, compared his company's #50000 in James Partington, "Avoidable Waste in Locomotive Operation as Affected by Design", No. 1816, December 1921 in Transactions of the American Society of Mechanical Engineers, Volume 43 (New York: The Society, 1922), 987-1011 In that article, he chose not to identify any of these rivals. (Thanks to Chris Hohl for his 9 February 2018 email pointing out several differences in the entire run of DL&W Pacifics. His specific comments appear below. Thanks to Randal O'Toole for his 28 August 2022 email noting an incorrect citation for Partington's paper.) The first five--works numbers 57053-57057 (road 1126-1130-)-came to the railroad in 1917. There followed works numbers 61790-61795, road 1120-1125 in 1920, works numbers 63248-63252, road 1115-1119 in 1922, and works numbers 64283-64287, road 1136-1140 in 1923.

After a long search, Locobase finally found a set of DL&W locomotive diagrams at [] (29 October 2003) and successfully matched this entry (with minor differences in heating surfaces) to one of Partington's examples.

The Lackawanna took delivery of several batches, all virtually identical but numbered in inverse order.The principal difference from the first batch (N-8) and the later three was a slightly larger area of arch tubes (37 sq ft vs 30 sq ft) in the firebox in the earliest quintet.

All of the N-9s, N-10s, and N-12s entered service with boilers set to 210 psi. Hohl's worksheet showed that the class was updated between 1927-1933 with boilers pressed to 225 psi (15.5 bar), which increased tractive effort to 42,366 lb (19,217 kg or 188.5 kN). Factor of adhesion fell to about 4.5, still high enough to limit slipperiness.

Hohl also showed that tender coal capacity increased to 16 tons and some tender water tanks were enlarged to 10,800 US gallons (40,878 litres). Loaded weights grew by varying levels. In the 1940 DL&W diagram book, tender weights ranged from 193,400 lb (87,725 kg) to 201,775 lb (91,524 kg) to 209,500 lb (94,574 kg) depending on water capacity and other changes.

Chris Hohl's research into streamlined and semi-streamlined locomotives turned up several examples in this class that were made over in such manner. All had a smooth face on the smokebox with centered headlight and shiny brass bell ahead of the stack. Six bright bands appeared to bind the lagging on the straight boiler from smokebox to the rear tubesheet. Chris also notes that the four had their Baker gear replaced by Walschaert, possibly for clearance reasons.

A valence stretched along the sides of the boiler, filling the space between the tops of the drivers and the cylinders and the running board. This panel was horizontally ruled with six lines at the head end, a solid section from there to near the back end, which had eight tapered "wingtips". Similar "wings" decorated the smokebox as a mustache for the headlight and the pilot had three feather-like stripes.

1117 and 1136's valences were light-colored, 1123's had more detailed "feathers" and lining against a dark background.

The last were retired in 1952.