The PRR Class K-4s was actually the fifth of six different classes of
4-6-2s the railroad ever owned following (by date) the K-28, K-2sa,
K-21s/VK-1, K-29, and K3s. What would eventually become the PRR Class
K-4s Pacifics resulted from an earlier Class E-6 Atlantic design,
incorporating the 4-4-2 wheel arrangement, and the American Locomotive
Company’s K-29 Pacific design. Mechanically the most famous features of
the K-4s' would be their Belpaire fireboxes, 80-inch drivers, and
Walschaerts valve gear, which blended just the right
amount of power and speed to haul virtually anything the PRR asked of
them. The PRR's designation for its K-4s was as follows: the "K"
denoted the railroad's fleet of Pacifics while the "4" was simply the
class number of the wheel arrangement; lastly, the "s" referred to the
class being superheated.
PRR Class K-4s Specifications
Builder – Baldwin Locomotive Works, Alco, And PRR's Juanita Shops
Fuel - 16 tons
Cylinders(2) - 27" x 28"
Water - 7,000 Gallons
Weight - 517,225 Pounds (Including Tender)
Diameter of Drivers – 80 Inches
Steam Pressure - 205 PSI
Tractive Effort – 44,460 Pounds
The PRR Class K-4s Pacifics were first constructed between 1910 and 1911 and they proved to be so successful that while most of the railroad's 4-6-2s were retired by the 1930s they would soldier on until all steam was retired from the property in the late 1950s. Most of the 450 K-4s units were built directly by the railroad's own Juniata, Pennsylvania shop forces (375) while Baldwin also chipped in with 75 examples. Interestingly, while versatile and able to pull serious tonnage the K-4s was not Pennsy's most powerful Pacific, which was the K-5 built in 1929 that by far had the highest tractive effort, boiler pressure, and overall weight of any 4-6-2 the railroad operated. Despite their power, however, the K-5 was not considered successful on the PRR. Below is a quick snapshot of the K-4s.
Incredibly, despite the fact that hundreds of 4-6-2s were put
into service on the Pennsylvania just two survived the scrappers
torch, Class K-4s #1361 current at the Railroaders Memorial Museum in Altoona and #3750 at the Railroad Museum of Pennsylvania. For years #1361 sat as a moment at
the railroad's fabled Horseshoe Curve in Pennsylvania after being
retired by the railroad in 1957. In 1986 the locomotive was removed
from its static display and
restored to operational status to pull excursions. After a lengthy
rebuild beginning in the late 1990s by the Horseshoe Curve Chapter of
the NRHS where millions of dollars had been spent without an operable
locomotive it was decided to put the restoration on hold due to rising
costs and return the Pacific to public display.
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