The Norfolk and Western Y3 and Y3a classes were classes of 2-8-8-2 "Mallet" articulated steam locomotives, with a total of 80 locomotives built for the Norfolk and Western Railway between 1919 and 1923.

The PRR classified articulated locomotives and joined locomotive units by using multiples of the previous classifications. Non-Articulated steam: 1320 - 2-2-2-0 locomotive, based on the London and North Western Railway 's Dreadnought Class locomotive.

The Pennsylvania Railroad class HH1s/Y3s are four-cylinder compound articulated locomotives that consist of six examples of ex-Norfolk and Western Railway Y3 class 2-8-8-2 (Whyte notation) wheel arrangement.

It is worth noting that the PRR had previously purchased six 2-8-8-2 Y3 locomotives from the N&S in 1943 and re-classed them as HH-1's. For the remainder of World War II they ran between Enola and Hagerstown and were later sent to Columbus.

The Y3 models were built in 1919 by ALCO and Baldwin and were used to haul long coal trains over mountainous terrain. Faced with motive power shortages during World War II, the Pennsylvania Railroad purchased six Alco-built Y3s from N&W in 1943.

Class Y3/Y3a (USRA) (Locobase 1421) Data from N&W 3-1955 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

HH1 – 2-8-8-2 – In 1943 the PRR aquired six Norfolk & Western Y3, 2-8-8-2, locomotives all built in 1919. They were used in Columbus for transfer and hump service. They could also be used on the Sandusky Branch as helpers.

In a departure from Pennsylvania practice, this engine used a wagon-top boiler with the longest tubes of any engine in Locobase. A further departure was the builder--Alco didn't send many engines to the Pennsy.

Dec 4, 2023 · The PRR uses the long tender with 3 axle trucks, the B&O uses the shorter tender with 2 axle trucks. The Y3 remains the only S gauge engine with whistle steam. Recently Ro advertised a sale that included the Y3’s.

Feb 11, 2010 · The PRR received 6 Y3 locomotives and used one for parts to keep the others in service. They were mostly used for pushers on the hump in Columbus and sometimes a transfer run from yard to yard. #373 was cannibalized for parts.