service. On July 2, 2016, SEPTA announced all 120 Silverliner V cars were being removed from service due to a "serious structural defect." At the time, the Silverliner V cars represent one-third of SEPTA's regional rail fleet. SEPTA also owns two Arrow II EMU cars built by GE in 1974 and once operated by New Jersey Transit for its electrified service to and from New York City and Hoboken Terminal (formerly NJT 1236 and 1237). The Arrow II car is nearly identical to that of the Silverliner IV, but lacks the distinctive dynamic brake roof "hump" on the car, and has a "diamond" pantograph instead of the "V" pantograph used on the Silverliner. The Arrow II are used as part of work trains, such as catenary inspection and leaf removal. The entire system uses 12 kV / 25 Hz overhead catenary lines that were erected by the PRR and Reading railroads between 1915 and 1938. All current SEPTA equipment is compatible with the power supplies on both the ex-PRR (Amtrak-supplied) and ex-Reading (SEPTA-supplied) sides of the system; the "phase break" is at the northern entrance to the Center City commuter tunnel between Jefferson Station and Temple University Station. In late 2014, and the beginning of early 2015, SEPTA began the "Rebuilding for the Future" campaign that will replace all deteriorated rolling stock and rail lines with new, modernized, equipment, including ACS-64 locomotives, bi-level cars, and better signaling. The ACS-64 locomotives for push-pull trains arrived in 2018 and replaced AEM-7 and ALP-44 locomotives. SEPTA passenger rolling stock includes: Electric multiple units Push-pull passenger cars Locomotives Electrification All lines used by SEPTA are electrified with overhead catenary supplying alternating current at 12 kV with a frequency of 25 Hz. The system on the former PRR side is owned and operated by Amtrak, part of the electrification of the Northeast Corridor. The electrification on the Reading side is owned by SEPTA. The Amtrak system was originally built by the PRR between 1915 and 1938. The SEPTA-owned system was originally built by the Reading starting in 1931. Yards and maintenance facilities SEPTA has four major yards and facilities for the storage and maintenance of regional rail trains: Frazer Yard, in Frazer, Pennsylvania, along the Paoli/Thorndale Line; services push-pull train sets. Overbrook Maintenance Facility, near Overbrook station on the Paoli/Thorndale Line; Services EMUs Powelton Yard, adjacent to 30th Street Station Roberts Yard, adjacent to Wayne