Locomotive, Steam, 4-4-4-4 T1

History: The Pennsylvania Railroad's 52 T1 class duplex-drive 4-4-4-4 steam locomotives, introduced in 1942 (2 prototypes) and 1945-1946 (50 production), were their last steam locomotives built and their most controversial. They were ambitious, technologically sophisticated, powerful, fast, and distinctively streamlined by Raymond Loewy. However, they were also prone to wheelslip both when starting and at speed, complicated to maintain, and expensive to run. The PRR vowed in 1948 to place diesel locomotives on all express passenger trains, leaving unanswered questions of whether the T1's flaws were solvable. An article in the Pennsylvania Railroad Technical and Historical Society Magazine published in 2008 revealed that the wheel-slip problems may have been caused by the failure to properly educate engineers transitioning to the T1, resulting in excessive throttle applications, which in turn caused the driving wheels to slip. Another root cause of wheel slip was faulty spring equalization. The drivers were equalized together and not equalized with the engine truck. In the production fleet, the PRR equalized the engine truck with the front engine and the trailing truck with the rear engine which helped to solve the wheel-slip problem.

From Wikipedia

Railroad/Company: The Pennsylvania Railroad (reporting mark PRR) was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy," the PRR was headquartered in Philadelphia, Pennsylvania.

The PRR was the largest railroad by traffic and revenue in the U.S. for the first half of the twentieth century. Over the years, it acquired, merged with or owned part of at least 800 other rail lines and companies. At the end of 1925, it operated 10,515 miles of rail line; in the 1920s, it carried nearly three times the traffic as other railroads of comparable length, such as the Union Pacific or Atchison, Topeka & Santa Fe railroads. Its only formidable rival was the New York Central (NYC), which carried around three-quarters of PRR's ton-miles.

At one time, the PRR was the largest publicly traded corporation in the world, with a budget larger than that of the U.S. government and a workforce of about 250,000 people. The corporation still holds the record for the longest continuous dividend history: it paid out annual dividends to shareholders for more than 100 years in a row.

In 1968, PRR merged with rival NYC to form the Penn Central Transportation Company, which filed for bankruptcy within two years. The viable parts were transferred in 1976 to Conrail, which was itself broken up in 1999, with 58 percent of the system going to the Norfolk Southern Railway (NS), including nearly all of the former PRR. Amtrak received the electrified segment east of Harrisburg.