The Pennsylvania Railroad bought its first 75 freight cars in 1849.
 Two years later, the Pennsy owned 439 freight cars.
By 1857, it had 1,861 cars, and in 1866, 9,379 cars.
Freight equipment was either acquired new from builders or built by the railroad itself.

The Pennsy acquired more cars from the railroads it absorbed.
In some instances, privately owned cars were either purchased from a builder or railroad acquisition.
One such example was the 1877 purchase of Empire Transportation merchandise and oil cars.

By the mid-1860s, the railroad had 9,379 freight cars; a decade later, 32,718; the mid-1880s, over 49,000; 1896, more than 87,000.

The Pennsy changed its car reporting methods around 1900.
The railroads owned and operated by the Pennsylvania Railroad system were now included in reports, in addition to the Pennsylvania Railroad proper.
So, in 1900, the Pennsy had over 180,000 freight cars; by 1910, 263,039.
The zenith of freight car ownership was reached in 1919 when the Pennsy owned a reported 282,729 freight cars.

Steel in freight car construction began during the later part of the 19th century, when cars were now being built with a steel underframe and wooden bodies or were all steel.
The Pennsy steadily replaced their wooden cars with steel versions until there were no more wooden cars by 1934.

During the first quarter of the 20th century, the average capacity of a Pennsylvania Railroad freight car increased from 31 tons to 54 tons.
This increased to 55 tons in the mid-1930s and then to 56 tons in 1945.

By the start of 1946, the Pennsy's freight car ownership decreased to 240,293 cars and in 1963, down to 140,535.

The Pennsylvania Railroad used a classification system for their freight cars.
Similar to their locomotives, the Pennsy used a letter system to designate the various types and sub-types of freight and maintenance cars.

A — Tank
F — Flat
G — Gondola
H — Hopper
R — Refrigerator
K — Stock
N — Cabin (Caboose)
S — Poling
T — Tool
U — Side Dump
W — Wreck Crane
X — Box
Y — Test Weight
Z — Business
The Pennsylvania Railroad bought its first 75 freight cars in 1849.  Two years later, the Pennsy owned 439 freight cars. By 1857, it had 1,861 cars, and in 1866, 9,379 cars. Freight equipment was either acquired new from builders or built by the railroad itself.
The Pennsy acquired more cars from the railroads it absorbed. In some instances, privately owned cars were either purchased from a builder or railroad acquisition. One such example was the 1877 purchase of Empire Transportation merchandise and oil cars.
By the mid-1860s, the railroad had 9,379 freight cars; a decade later, 32,718; the mid-1880s, over 49,000; 1896, more than 87,000.
The Pennsy changed its car reporting methods around 1900. The railroads owned and operated by the Pennsylvania Railroad system were now included in reports, in addition to the Pennsylvania Railroad proper. So, in 1900, the Pennsy had over 180,000 freight cars; by 1910, 263,039. The zenith of freight car ownership was reached in 1919 when the Pennsy owned a reported 282,729 freight cars.
Steel in freight car construction began during the later part of the 19th century, when cars were now being built with a steel underframe and wooden bodies or were all steel. The Pennsy steadily replaced their wooden cars with steel versions until there were no more wooden cars by 1934.
During the first quarter of the 20th century, the average capacity of a Pennsylvania Railroad freight car increased from 31 tons to 54 tons. This increased to 55 tons in the mid-1930s and then to 56 tons in 1945.
By the start of 1946, the Pennsy's freight car ownership decreased to 240,293 cars and in 1963, down to 140,535.
The Pennsylvania Railroad used a classification system for their freight cars. Similar to their locomotives, the Pennsy used a letter system to designate the various types and sub-types of freight and maintenance cars.
A — Tank
F — Flat
G — Gondola
H — Hopper
R — Refrigerator
K — Stock
N — Cabin (Caboose)
S — Poling
T — Tool
U — Side Dump
W — Wreck Crane
X — Box
Y — Test Weight
Z — Business
Pennsylvania Railroad