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BALDWIN I1sa class 2-10-0 Type E "Decapod" steam locomotive



The first 2-10-0 "Decapod" steam locomotive was built as early as 1867 for the Lehigh Valley Railroad. The Decapod Type was essentially an extension of the very successful Consolidation Type, a 2-8-0 design, named class H for the PRR. This locomotive is also known as "russian decapod", because it was ordered in large numbers (1.200 engines)in the Russian Empire during World War I.
The I1s class 2-10-0 was considered the standard heavy freight hauler of the Pennsylvania Railroad up until WWII. They served primarily in mountainous areas of central Pennsylvania and the lakes Erie and Ontario, for transportation of coal (Pittsburgh Region, Central Region and Northern Region).
The PRR decapod was unlike the Russian decapod; it was huge, taking advantage of the PRR's heavy trackage and high axle loading, with a fat, free-steaming boiler that earned the type the nickname of 'Hippos' on the PRR.
In 1930, the original I1s underwent a revision of the cylinder steam vents to admit steam for 78% of the stroke. This boosted tractive effort from 90,000 to 96,000 lbs and made the new class I1sa. Through the years, many I1s engines were changed over to the modified I1sa design. By July 1947, the 598-unit fleet was divided into 109 I1s and 489 I1sa locomotives. They remained in service until the end of PRR's era steam in 1957.

Specifications / Technical data
Builders: PRR Juniata Shops, Baldwin
Production: 1916-1923
Total production: 123 Type-A I1s - 475 Type-E I1sa
PRR roster: 598 (1916-1957)
Wheels: 2-10-0 (UIC 1-E-0)
Loco weight: 386.100 lb (no tender)
Lenght:
Power: Coal/Oil
Gauge: 4 ft 8,5 in
Driver diameter: 62"
Cylinders: 2 (30,5x32 in)
Valve gear: Walschaerts
Pressure: 250 psi
Tractive effort: 102.027 lbf

Baldwin I1sa class Pennsylvania Railroad #4315 data
Road Number: 4315
Road Number   Sequence: 1st
Type: 2-10-0
Class: I1s, I1sa
Builder: Baldwin
Built: 1922
CN: 55817
Disposition: sold for scrapped 10/59
Previous   Owner:
Remarks: rebuilt 7/41 I1sa long tender
Serial Number: 9415
Assignment 1953: Central Region - Lake Division

Baldwin I1sa class Pennsylvania Railroad #4473 data
Road Number:
4473
Road Number   Sequence: 1st
Type: 2-10-0
Class: I1s, I1sa
Builder: Baldwin
Built: 1923
CN: 56496
Disposition: sold for scrapped 8/59
Previous Owner:
Remarks: rebuilt 5/43 I1sa short tender
Serial Number: 9573
Assignment 1954/1957: Pittsburgh Division

Designed to haul heavy freight trains on Pennsylvania main lines, the PRR's "decapod" were named "hippo" by "pennsy" railroad crew and, later, by fans. I1sa class served "the standard railrod of the world" for many years, pulling coal trains, switching cars on yard, helping merchandise consists in every parts of the huge PRR network.


I1sa class No.4315 on Elmira Branch line
(Courtesy by Classic Trains magazine - Photo J. Shaughnessy copyrighted)


I1sa class No.4473 at Cresson Yard in 1948.

BROADWAY LIMITED IMPORTS PARAGON 2 Baldwin 2-10-0 I1sa class Pennsylvania Railroad  No 4473
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