The Pennsylvania Railroad was completed to Pittsburgh, PA from Harrisburg, PA in 1854. The route followed the watersheds of the Conemaugh River on the west and the Juniata River on the east. The tools available for construction were based upon manpower with horsepower. Picks, axes, shovels, wheel barrels, wagons, scrapers and black powder were the tools. The outcome was a route soundly based upon civil engineering practices of the 1850's. The biggest problem was building a railroad over the Allegheny frontal. The Allegheny frontal is the physical barrier between the Ridge and Valley section of Pennsylvania's geography and the Appalachian Plateau. J. Edgar Thomson was the civil engineer that designed the route over the Allegheny frontal beginning at Altoona and ending at Gallitzin, PA. In the center of the eleven mile grade is the Horseshoe Curve.
The Pittsburgh to Harrisburg line remains today essentially upon the same 1850's route and alignment.
The Pennsylvania Railroad (PRR) in 1910 operated 30 daily passenger trains between Pittsburgh and Harrisburg. The fastest schedule was 6 hours. In 1950, 50 daily passenger trains were operated with the best schedule being 5 hours. Today the railroad is owned by the Norfolk Southern. Amtrak operates 2 daily passenger trains on a 5 and 1/2 hour schedule.
Government policy caused a decline in the railroad industry beginning in the 1950's. The then Interstate Commerce Commission followed a policy that failed to allow adequate rate increases for both passenger rates and freight rates. Railroad industry consolidation that might have allowed for a rational private sector solution to changed business conditions was delayed by the Interstate Commerce Commission such that the Penn Central Company, an attempt by the Pennsylvania Railroad and parallel competitor New York Central Railroad to merge and remain economically viable in 1968 was so fragile that damage caused by the 1972 Agnes hurricane pushed the struggling enterprise into bankruptcy.
The American railroad industry by 1971 was burdened with an unprofitable passenger train operation. Congress created the National Railroad Passenger Corporation. It operates as Amtrak. The railroad companies would no longer own and operate passenger trains. The railroads would provide the railroad line for which Amtrak would operate passenger trains. The exception is the former Pennsylvania Railroad lines in the Northeast Corridor. Amtrak acquired the railroad as well as owned passenger equipment and operated passenger trains. Outside of the Northeast Corridor, Amtrak owns the railroad line from Kalamazoo, MI to Porter, IN, portions of the Empire Corridor in New York, and the New Haven, CT to Springfield, MA. And, Amtrak owns the Keystone Corridor East from Harrisburg to Philadelphia, PA where the line connects with the Northeast Corridor.
By 1976, the railroad industry in the Northeastern United States was in such distress that Congress created the Consolidated Railroad Corporation or Conrail. The new corporation was composed of the former Penn Central Railroad Company and other railroad Companies such as the Erie - Lackawanna Railroad, Reading Railroad, Central Railroad of New Jersey, Ann Arbor Railroad.
The Pittsburgh to Harrisburg line under Conrail was rebuilt with welded rail.
In 1999 the Norfolk and Southern Railroad together with the CSX Railroad bought Conrail roughly along the lines of the former Pennsylvania Railroad lines becoming controlled by the Norfolk and Southern and the former New York Central lines becoming controlled by the CSX Railroad.
The Keystone Corridor West, Pittsburgh to Harrisburg is owned by the Norfolk and Southern Railroad with a dramatic heavy freight railroad operation. The Keystone Corridor East, Harrisburg to Philadelphia is owned by Amtrak and its principle purpose is to provide passenger service with some freight service provided by the Norfolk and Southern.