The reference for locomotives and railcars


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Lehigh Valley class J-55½
United States | 1904 | 105 produced
Ron Ziel, „American Locomotives 1858 to 1949”

The Lehigh Valley had the ability to source large quantities of smaller fragments of anthracite coal as residues from the processing operation at less than a dollar a ton. In order to be able to use these as fuel for steam locomotives, the camelback design was used with a very wide firebox, which included a large grate area. From 1904, a larger series of ten-wheelers was produced, which were suitable for use in front of fast freight trains in the lowlands and heavy local trains.

The locomotives were designed so heavy that the axle load was just suitable for high speeds. The large firebox was a slightly modified Wootten type and did not have a combustion chamber. The load on the individual coupled axles was distributed more rear-heavy to get better traction when starting. The initial wheel diameter of 68.5 inches represented a good compromise between higher speeds and a tractive effort of more than 30,000 pounds

There were some changes during production, for example the wheel diameter was increased to 69 inches. While the boiler initially had 378 tubes, this number was reduced to 363 from 1907. With the exception of Baldwin's last delivery, all locomotives had Stephenson-type valve gear. Of the last Baldwin engines, eight had Walschaert valve gear and two had Baker-Pilliod valve gear.

Variant1904 variant1907 variantsuperheated
ManufacturerALCO, BaldwinLehigh Valley
Axle config4-6-0 (Ten-wheeler) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length57 ft 1 1/4 in
Wheelbase25 ft 4 in
Fixed wheelbase13 ft 4 in
Total wheelbase65 ft 7 in
Service weight199,200 lbs203,000 lbs207,200 lbs
Adhesive weight150,200 lbs154,000 lbs155,000 lbs
Total weight354,400 lbs358,200 lbs
Axle load50,200 lbs53,700 lbs55,200 lbs
Water capacity8,000 us gal
Fuel capacity24,000 lbs (coal)
Power sourcesteam
Estimated power1,650 hp (1,230 kW)1,625 hp (1,212 kW)1,700 hp (1,268 kW)
Optimal speed33 mph35 mph
Starting effort31,411 lbf31,183 lbf
Power Plant
Driver diameter68.5 in69 in
Boiler pressure205 psi
Expansion typesimple
Cylinderstwo, 21 x 28 in
Grate area85 sq ft
Firebox area200 sq ft199 sq ft
Tube heating area3,084 sq ft2,960 sq ft2,171 sq ft
Evaporative heating area3,284 sq ft3,159 sq ft2,370 sq ft
Superheater area493 sq ft
Total heating area3,284 sq ft3,159 sq ft2,863 sq ft
Calculated Values
steam locomotive
last changed: 09/2022

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