Starting in 1929, DL&W began to receive thirty new "Poconos" (road numbers 1601 through 1620 Class Q-2 and 1621 through 1630 Class Q-3) from ALCO. These were intended for freight service and had 70" drivers and a tractive force of 71,600 pounds.
In 1934, it purchased 20 more Class Q-4 (road numbers 1631 through 1650) ALCO "super power" 4-8-4s, this time intended for dual service. They were designed to have 74" drivers, a tractive effort of 72,000 pounds and roller bearings on all axles.
There are no survivors
|Class||Road Numbers||Year Built||Builder|
In his study of the USRA Heavy Mountain (see Locobase 232) and the locomotives it inspired, LeMassena notes that the DL&W had procured five 4-8-2s based on the USRA design but equipped with larger fireboxes ( Locobase 5731). Soon the railroad came back for still bigger descendants of the basic design that needed another axle under the firebox. Thus were erected the first DL&W 4-8-4s. Firebox heating surface area included 28 sq ft (2.6 sq m) in arch tubes and 88 sq ft (8.18 sq m) more in thermic syphons. Piston valves measured a relatively modest 12" (305 mm) in diameter in cast-steel cylinders. The quintet's 77" (1,956 mm) driver diameter was unequalled in any of the other DL&W 4-8-4s
These were delivered with tenders holding 14 ton of coal and weighed 216,000 lb (97,976 kg). Mechanical stoker was the Standard Type B.
Called Poconos, this group of five engines led the way for 50 more; see Locobases 260,
9246, and 924.
Unlike every other US 4-8-4 design, the D&LW Qs (see also 260) used the smaller flues for its Type A superheater tubes. All others using Type As had 5 1/2" flues.
The next step in the DL&W's Pocono parade belonged to this dual-traffic design. Simliar in most respects to the Brooks-built Q1 (Locobase 259), the new class had smaller drivers and were expected to haul fast freights as well as passenger trains. Firebox had 110.5 sq ft (10.25 sq m) of thermic syphons and 27.5 sq ft (2.55 sq m) of arch tubes contributing to the heating surface.
NB: Unlike every other US 4-8-4 design, the D&LW Qs (see also 259) used the smaller flues for its Type A superheater tubes. All others using Type As had 5 1/2" flues.
This class represented a big boiler redesign compared to the Q2s that had preceded it only a few years earlier (see Locobase 260). Superpower dimensions had arrived: the number of firetubes shrank dramatically while scores of new, smaller-diameter flues for the Type E superheated resulted in an 69% increase in supeheater area (or more than 900 sq ft). The firebox saw little change and had 110 sq ft of thermic syphons and 27 sq ft of arch tubes contributing to the heating surface. They introduced the Worthington 5-S feed water heater with a 9,000 US gallon (34,065 litres)/hour capacity. The DL&W estimated resulting quantities as 5-8% in coal and 3-5% in water.
Also, LeMassena notes, the Q3s pioneered roller bearings on the Lackawanna with the first 8 (Q3) sporting roller bearings on the lead trucks and the last two (Q3a) fitted with roller bearings on all engine axles.
The last variant of the DL&W's sizable 4-8-4 stud, the Q4 also sported a superpower boiler on a slightly smaller scale than the Q3 (Locobase 9246), but pressed to a higher degree. The firebox, too, was a bit smaller with 95 sq ft (8.82 sq m) of thermic syphons and 27 sq ft (2.5 sq m) of arch tubes contributing to the heating surface. Driver diameter increased by 4" and the Q4s also traveled on roller bearings on all engine axles.
Worthington's 5-SA feed water heater offered a 9,000 US gallon (34,065 litres)/hour capacity. As in the Q-3s (which had the 5-S type), DL&W estimated resulting quantities as 5-8% in coal and 3-5% in water.
LeMassena says: "Although intended for fast freight trains between Buffalo and Binghamton, New York, these locomotives handled perishables eastward to Hoboken, New Jersey, returning westward on mainline passenger trains."
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Delaware, Lackawanna &Western||Delaware, Lackawanna &Western||Delaware, Lackawanna &Western||Delaware, Lackawanna &Western|
|Number in Class||5||20||10||20|
|Locomotive Length and Weight|
|Driver Wheelbase (ft)||20||19||19||19.50|
|Engine Wheelbase (ft)||46.67||45.50||45.50||46.08|
|Ratio of driving wheelbase to overall engine wheebase||0.43||0.42||0.42||0.42|
|Overall Wheelbase (engine & tender) (ft)||82.21||84.62||84.62||86.54|
|Axle Loading (Maximum Weight per Axle) (lbs)|
|Weight on Drivers (lbs)||269,000||262,000||270,000||274,000|
|Engine Weight (lbs)||421,000||418,000||432,000||447,000|
|Tender Loaded Weight (lbs)||221,500||289,000||287,200||313,000|
|Total Engine and Tender Weight (lbs)||642,500||707,000||719,200||760,000|
|Tender Water Capacity (gals)||12,000||15,000||15,000||16,000|
|Tender Fuel Capacity (oil/coal) (gals/tons)||16||22||22||26|
|Minimum weight of rail (calculated) (lb/yd)||112||109||113||114|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in)||77||70||70||74|
|Boiler Pressure (psi)||250||230||235||250|
|High Pressure Cylinders (dia x stroke) (in)||27" x 32"||28" x 32"||28" x 32"||28" x 32"|
|Tractive Effort (lbs)||64,379||70,067||71,590||72,043|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.18||3.74||3.77||3.80|
|Firebox Area (sq ft)||493||515||513||493|
|Grate Area (sq ft)||88.20||88.20||88.20||88.20|
|Evaporative Heating Surface (sq ft)||5193||5136||5445||5488|
|Superheating Surface (sq ft)||1324||1324||2243||2180|
|Combined Heating Surface (sq ft)||6517||6460||7688||7668|
|Evaporative Heating Surface/Cylinder Volume||244.89||225.21||238.76||240.64|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||22,050||20,286||20,727||22,050|
|Same as above plus superheater percentage||26,460||24,343||26,738||28,224|
|Same as above but substitute firebox area for grate area||147,900||142,140||155,516||157,760|