Delaware, Lackawanna & Western / Delaware, Lackawanna &Western 4-6-2 "Pacific" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class N (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.

This septet of Pacifics was not used in passenger service, but rather as fast freight engines. So 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 4 feet. Also, the engines now put 258,000 lb on the drivers, a hefty increase.

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 - 1933 Locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection. 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 11" (279 mm) piston valves. 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.

Class N-12 (Locobase 3752)

Data from DL&W locomotive diagrams at (29 October 2003).

The last of the Lackawanna's freight Pacifics (Brooks works #65398-65407) and a short-lived bunch at that. Within 5 years, some were already being converted to heavy 0-8-0 switchers.

In 1943, the Boston & Maine bought 4 of the class, designating them P-5a and numbering them 3696-3699. In that livery, they carried on until 1951-1952, when most B & M steam was retired.

Class N-5 (Locobase 3094)

See DL&W locomotive diagrams at (29 October 2003). 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 . Unlike the Alco engines of a year earlier, however, these engines were later converted to 0-8-0 switchers -- 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 10 years.

The last two were Schenectady-built in 1916.

Railway Age of 9 October 1914 (Vol. 57, No. 15) 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.

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 2 "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.

Class N-6 (Locobase 6293)

See Railway Mechanical Engineer for January 1916 for details on this class. 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]." 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.

The last of this class retired in 1953.

Class N-7 (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).

1172-1178 were delivered in 1916, 1179-1183 in 1922 (works #63606-63610). The latter 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.

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

One of the locomotives to which James Partington, Estimating Engineer for Alco, compared his company's #50000 in "Avoidable Waste in Locomotive Operation as Affected by Design", Railway Age, Volume 95, No. 11 (5 November 1921), pp. 673-677. In that article, he chose not to identify any of these rivals.

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 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. 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.

Chris Hohl's research into streamlined and semi-streamlined locomotives has 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.

These were the last Pacifics built new for the DL&W and together with the N-1s of a slightly earlier vintage constituted the 4-6-2s on the line. Some were shrouded in streamlining frills that consisted of a convex smokebox cover, and a deep, winged valence.

The last were retired in 1952.

Specifications by Steve Llanso of Sweat House Media
Locobase ID7582 144 3752 3094 5735
RailroadDelaware, Lackawanna &WesternDelaware, Lackawanna &WesternDelaware, Lackawanna &WesternDelaware, Lackawanna & WesternDelaware, Lackawanna & Western
Number in Class71410141
Road Numbers1151-11571101-11141184-11931158-1170, 1172-11731171
Number Built71410141
Valve GearWalschaertWalschaertBakerWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase13'13'13'13'13'
Engine Wheelbase33.83'34.83'33.83'33.83'33.83'
Ratio of driving wheelbase to overall engine wheebase 0.38 0.37 0.38 0.38 0.38
Overall Wheelbase (engine & tender)66.08'67.25'69.87'66.33'66.33'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers186500 lbs186500 lbs190500 lbs188000 lbs189600 lbs
Engine Weight286000 lbs290000 lbs297500 lbs291000 lbs297600 lbs
Tender Light Weight164500 lbs165400 lbs185700 lbs165400 lbs165400 lbs
Total Engine and Tender Weight450500 lbs455400 lbs483200 lbs456400 lbs463000 lbs
Tender Water Capacity9000 gals9000 gals10000 gals9000 gals9000 gals
Tender Fuel Capacity (oil/coal)10 tons10 tons10 tons10 tons10 tons
Minimum weight of rail (calculated)104 lb/yard104 lb/yard106 lb/yard104 lb/yard105 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter69"73"69"69"69"
Boiler Pressure200 psi200 psi200 psi200 psi200 psi
Cylinders (dia x stroke)25" x 28"25" x 26"25" x 28"25" x 28"25" x 28"
Tractive Effort43116 lbs37842 lbs43116 lbs43116 lbs43116 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.33 4.93 4.42 4.36 4.40
Heating Ability
Firebox Area221 sq. ft276 sq. ft285 sq. ft288 sq. ft319 sq. ft
Grate Area58 sq. ft94.50 sq. ft58.10 sq. ft58 sq. ft68.60 sq. ft
Evaporative Heating Surface3990 sq. ft3844 sq. ft3447 sq. ft3465 sq. ft3494 sq. ft
Superheating Surface808 sq. ft821 sq. ft756 sq. ft740 sq. ft740 sq. ft
Combined Heating Surface4798 sq. ft4665 sq. ft4203 sq. ft4205 sq. ft4234 sq. ft
Evaporative Heating Surface/Cylinder Volume250.82260.23216.68217.82219.64
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1160018900116201160013720
Same as above plus superheater percentage1357222302137121368816052
Same as above but substitute firebox area for grate area5171465136672606796874646
Power L11788020777168811672116987
Power MT634.08736.82586.08588.25592.56

Specifications by Steve Llanso of Sweat House Media
Locobase ID6293 5736 3306
RailroadDelaware, Lackawanna &WesternDelaware, Lackawanna &WesternDelaware, Lackawanna &Western
Number in Class51221
Road Numbers1131-11351172-11831115-1130, 1136-1140
Number Built51221
Valve GearWalschaertBakerBaker
Locomotive Length and Weight
Driver Wheelbase13'13'14'
Engine Wheelbase34.42'33.83'24.60'
Ratio of driving wheelbase to overall engine wheebase 0.38 0.38 0.57
Overall Wheelbase (engine & tender)67.08'66.48'72.42'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers197100 lbs187500 lbs192500 lbs
Engine Weight305500 lbs295000 lbs302000 lbs
Tender Light Weight165800 lbs164200 lbs177400 lbs
Total Engine and Tender Weight471300 lbs459200 lbs479400 lbs
Tender Water Capacity9000 gals9000 gals10000 gals
Tender Fuel Capacity (oil/coal)10 tons10 tons10 tons
Minimum weight of rail (calculated)110 lb/yard104 lb/yard107 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter73"69"79"
Boiler Pressure200 psi200 psi210 psi
Cylinders (dia x stroke)27" x 28"25" x 28"25" x 28"
Tractive Effort47535 lbs43116 lbs39541 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.15 4.35 4.87
Heating Ability
Firebox Area369 sq. ft289.15 sq. ft338 sq. ft
Grate Area91.30 sq. ft58 sq. ft94.70 sq. ft
Evaporative Heating Surface3680 sq. ft3466 sq. ft3186 sq. ft
Superheating Surface808 sq. ft740 sq. ft649 sq. ft
Combined Heating Surface4488 sq. ft4206 sq. ft3835 sq. ft
Evaporative Heating Surface/Cylinder Volume198.33217.88200.28
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation182601160019887
Same as above plus superheater percentage215471368823268
Same as above but substitute firebox area for grate area870846823983047
Power L1167821673118627
Power MT563.13590.17639.98



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