of the Pennsy fleet until 1957. The Pennsy's reliance on steam locomotives in the mid-20th century contributed to its decline. Steam locomotives require more maintenance than diesel locomotives, are less cost efficient, and require more personnel to operate. Plus, coaling and watering facilities and machine shops added greatly to steam-related costs. Like other railroads, the Pennsy was unable to update its roster at will during the World War II years; by the end of the war their roster was in rough shape. In addition, the Pennsy was saddled with unsuccessful experimental steam locomotives such as the Q1, S1, and T1 "Duplex Drive" locomotives, and the S2 turbine locomotive. Unlike most of their competition, the Pennsy did not acquire any Northerns or Berkshires. Pennsy competitors managed this period better with their diesel locomotive rosters. The Pennsylvania Railroad voluntarily preserved a roundhouse full of representative steam locomotives at Northumberland, Pennsylvania in 1957 and kept them there for several decades. These locomotives, with the exception of I1sa #4483 which is on display at Hamburg, New York, are now at the Railroad Museum of Pennsylvania in Strasburg, Pennsylvania. In sharp contrast, the New York Central's President, Alfred E. Perlman, deliberately scrapped all but two steam locomotives, with the older one (L2d) surviving only by accident. On December 18, 1987, the State of Pennsylvania designated the Pennsy's K4s as the official State Steam Locomotive. The two surviving K4s are No. 1361, which is undergoing restoration to operating condition at the Railroaders Memorial Museum in Altoona, and No. 3750, which remains on static display at the Pennsylvania Railroad Museum in Strasburg. the only operable Pennsylvania Railroad steam locomotive is class B4a engine # 643, built in July 1901 in Altoona. Engine 643 is maintained by volunteers of the Williams Grove Historical Steam Engine Association outside of Harrisburg, and is operated several weekends each summer. however, a major construction project has been underway since 2014, building a new operational example of a class T1 engine numbered 5550, as all original class T1 locomotives have been scrapped. The project is being undertaken by the Pennsylvania Railroad T1 Steam Locomotive Trust and is projected to be finished by 2030. Electric When work on the Hudson River tunnels and New York's Penn Station was in progress, the type of electric locomotives to be used was an important consideration. At that time only a few electric locomotives existed. Several experimental locomotives