On February 6, 1951, a Pennsylvania Railroad train derailed on a temporary wooden trestle in Woodbridge, New Jersey, killing 85 passengers. It remains New Jersey's deadliest train wreck, the deadliest U.S. derailment since 1918, and the deadliest peacetime rail disaster in the United States.

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 was headquartered in Philadelphia, Pennsylvania. It was so named because it was established in the Commonwealth of Pennsylvania.

By 1882, the Pennsylvania Railroad had become the largest railroad (by traffic and revenue), the largest transportation enterprise, and the largest corporation in the world. Its budget was second only to the U.S. government. The corporation still holds the record for the longest continuous dividend history: it paid out annual dividends to shareholders for more than 100 consecutive years.Over the years, it acquired, merged with or owned part of at least 800 other rail lines and companies. At the end of 1926, it operated 11,640.66 miles (18,733.83 kilometers) of rail line; in the 1920s, it carried nearly three times the traffic as other railroads of comparable length, such as the Union Pacific and Atchison, Topeka & Santa Fe railroads. Its only formidable rival was the New York Central (NYC), which carried around three-quarters of the Pennsy's ton-miles.

In 1968, the Pennsylvania Railroad merged with its rival New York Central Railroad and the railroad eventually went by the name of Penn Central Transportation Company, or "Penn Central" for short. The former competitors’ networks integrated poorly with each other, and the railroad filed for bankruptcy within two years.: Chapter 1 Bankruptcy continued and on April 1, 1976, the railroad gave up its railroad assets, along with the assets of several other failing northeastern railroads, to a new railroad named Consolidated Rail Corporation, or Conrail for short. Conrail was itself purchased and split up in 1999 with 58 percent of the system going to the Norfolk Southern Railway (NS), including nearly all of the remaining former Pennsylvania Railroad. US passenger carrier Amtrak received the electrified segment of the Main Line east of Harrisburg.

After 1976, the railroad eventually became an insurance company and now goes by the name of American Premier Underwriters and is now a subsidiary of American Financial Group.