By the turn of the 20th century many of the larger railroads realized
that they were running into a problem; passenger trains were becoming
larger and heavier as demand steadily increased which was resulting in
multiple units needed to keep these expedited consists on a strict schedule.
In 1902 the Chesapeake & Ohio was the first to put the 4-6-2
design into regular service for the very reasons mentioned above.
Somewhat surprisingly, it was not until 1906 that the Pennsylvania
Railroad began looking at the possibility of utilizing such a locomotive
for passenger operations. In 1907 the PRR collaborated with the
American Locomotive Company's (Alco) Pittsburgh Works to build an
Interestingly, even here the railroad was still quite slow, deliberate,
and calculated in its approach with the new locomotive. This first
4-6-2 was given road number 7067 and listed as Class K-28; it featured
80-inch drivers, a tractive effort of nearly 33,000 pounds, and weighed
more than 208 tons (including tender). For an early Pacific design it
was quite heavy in comparison to the C&O's examples (by more than 53
tons) with a tractive effort slightly better. This would be the only
4-6-2 of this class and it was later superheated and designated as Class
K-28s before being scrapped in 1933. In any event, the PRR was quite
pleased with its trials and decided on the Pacific as its primary power
for passenger service.
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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