Pennsylvania (PRR) Steam Roster: Post 1906

Published: March 26, 2024

By: Adam Burns

The Pennsylvania Railroad (PRR), often called the "Pennsy," first established in 1846, quickly rose to dominance as the largest railroad by traffic and revenue in the U.S. throughout the first half of the 20th century.

The birth of PRR was a bid by Pennsylvania to compete with the Erie Canal, New York's commercial supremacy. Pennsy was a unit of the extensive Pennsylvania System, which included several companies it had acquired over the years through consolidation, leasing or outright purchase.

It built a dense network of lines veining across the northeastern U.S, spanning over 10,000 miles by the early 20th century. The Pennsy's robust growth was deeply woven into the fabric of America's socio-economic development, transporting freight and passengers over its vast network. Its iconic streak of Red Keystone logo symbolized its widespread influence.

The introduction of steel rail, refining the track signal system, and embracing technological advancements elevated PRR's status as a leading innovator.

Highpoints included famously difficult engineering feats such as the horseshoe curve and the Pennsylvania station. Despite enhancements, Pennsylvania Railroad was struck by challenges post-WWII, leading to its merger with its longtime rival, New York Central, forming Penn Central in 1968.

As the largest, and most successful, railroad through the World War II period, the Pennsy utilized a wide range of wheel arrangements during the steam era, and was a big proponent of the Belpaire firebox.

The Belpaire firebox was a distinctive component utilized exceptionally by the Pennsylvania Railroad in their locomotives. Invented by Belgian engineer Alfred Belpaire, this firebox's unique design consisted of a sloping, rectangular shape with a flat top, diverging from the traditional round-top fireboxes.

The benefit of this innovation was twofold: firstly, it offered a larger surface area for heat transfer, facilitating more efficient boiler performance. Secondly, the flat top provided structural strength, negating the need for stay bolts that were typical in earlier designs, thus simplifying maintenance procedures.

Pennsylvania Railroad's widespread adoption of the Belpaire firebox appears counterintuitive to some, given that other railroads preferred radial stay fireboxes or the wagon-top design. This choice was rooted in the company's belief in this design's enhanced structural stability, efficiency, and simplicity.

Furthermore, the Pennsylvania Railroad could manufacture the Belpaire design more cost-effectively, as demonstrated by their production capabilities at the Altoona Works.

These factors made the Belpaire firebox an integral part of the identity of the Pennsylvania Railroad, symbolizing their dedication to practicality, efficiency, and innovative engineering solutions.

Therefore, despite not being universally used across all railroads, the Belpaire firebox remains iconically associated with the Pennsylvania Railroad, justifying its prominence in historical records.

Interestingly, however, due to the railroad's relatively easy grades through central Pennsylvania, it did not maintain a fleet of large articulated, or Mallet, steam locomotives.

In general freight service it predominantely relied on 2-8-2s, and 2-10-4s for heavier assignments, while 4-6-2s were generally tapped for passenger trains.

Roster (Post 1906)

Sources

• Drury, George H. Guide To North American Steam Locomotives: Revised Edition. Waukesha: Kalmbach Books, 2015.

• Morrison, Tom. American Steam Locomotive In The Twentieth Century. Jefferson: McFarland & Company, Inc., 2019.

• Schafer, Mike and Solomon, Brian. Pennsylvania Railroad. Osceola: MBI Publishing, 1997.

• Staufer, Alvin F. Pennsy Power: Steam and Electric Locomotives of the Pennsylvania Railroad, 1900-1957. Brattleboro: Echo Point Books & Media, 2019.