The

Pennsylvania Railroad The Pennsylvania Railroad (reporting mark PRR), legal name The Pennsylvania Railroad Company also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. It was named ...

's N1s was a class of

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomot ...

built for Lines West. They were of

2-10-2 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of two leading wheels, ten powered and coupled driving wheels, and two trailing wheels. In the United States of America and elsewhere the is ...

"Santa Fe" wheel arrangement, ten driving wheels with a two-wheel leading truck and a two-wheel cast KW-pattern trailing truck under a giant firebox. This arrangement was well suited to the N1s' intended purpose, which was as a heavy

drag freight A drag freight is a long, slow, high-tonnage railroad train, often carrying commodities such as coal or ore. Compared to "fast freight" trains, drag freight trains have a very low power-to-weight ratio, making them somewhat unpredictable on steep ...

engine for coal and iron ore traffic to and from lakeside ports. The design was developed by the PRR's

Fort Wayne Fort Wayne is a city in and the county seat of Allen County, Indiana, United States. Located in northeastern Indiana, the city is west of the Ohio border and south of the Michigan border. The city's population was 263,886 as of the 2020 Censu ...

Shops and orders were placed with Alco (Brooks) (35 locomotives) and Baldwin (25 locomotives) for a total of 60; the first Alco locomotive was delivered in December 1918, with the remainder arriving during 1919. The N1s was a large locomotive; the boiler was the largest then used on any non-experimental PRR locomotive, with a large

Belpaire firebox The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium in 1864. Today it generally refers to the shape of the outer shell of the firebox which is approximately flat at the top and squa ...

with of grate area and a long combustion chamber. No feedwater heater was fitted, but a mechanical stoker and power reverse were, necessities on such a large locomotive. Boiler pressure was , although it was designed to take a pressure of . To allow the locomotive to negotiate tight 23-degree curves, the first and fifth driving axles were fitted with

lateral motion device A lateral motion device is a mechanism used in some railroad locomotives which permits the axles to move sideways relative to the frame. The device facilitates cornering. Purpose Prior to the introduction of the lateral motion device, the coupled ...

s and the center axle was blind. In many respects, the N1s was similar in ability to the I1s

2-10-0 Under the Whyte notation for the classification of steam locomotives, 2-10-0 represents the wheel arrangement of two leading wheels on one axle, ten powered and coupled driving wheels on five axles, and no trailing wheels. This arrangement was of ...

"Decapod". Driver diameter, weight on drivers and cylinder size were almost identical. The N1s' boiler was larger, but of a lower pressure. The I1s'

tractive effort As used in mechanical engineering, the term tractive force can either refer to the total traction a vehicle exerts on a surface, or the amount of the total traction that is parallel to the direction of motion. In railway engineering, the term tr ...

was a little higher, while the N1s had a superior factor of adhesion. The N1s, as a low-speed drag hauler, was limited to , while the I1s was capable of or greater. The N1s were the first class of large power withdrawn after

diesel locomotive A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving whee ...

s appeared; all were gone by 1950, and none were saved for display. Their task, low-speed drag haulage, was the diesel locomotive's forte.

References

{{PRR locomotives ALCO locomotives Baldwin locomotives 2-10-2 locomotives N1s Steam locomotives of the United States Scrapped locomotives Freight locomotives Standard gauge locomotives of the United States