Amtrak's 25 Hz traction power system
Amtrak's 25 Hz traction power system is a traction power network for the southern portion of the Northeast Corridor (NEC), the Keystone Corridor, and several branch lines between New York City and Washington D.C. The system was constructed by the Pennsylvania Railroad between 1915 and 1938 before the North American power transmission grid was fully established. This is the reason the system uses 25 Hz, as opposed to 60 Hz, which is the standard frequency for power transmission in North America. The system is also known as the Southend Electrification, in contrast to Amtrak's 60 Hz traction power system that runs between Boston and New Haven, which is known as the Northend Electrification system.
Amtrak Avelia Liberty trainset operating under the 25 Hz traction power system near Claymont, Delaware
Old substation built for the 1915 electrification project at Bryn Mawr, Pennsylvania. Outdoor yard is an addition.
The Safe Harbor Dam generates 25 Hz railroad power via two turbines in the east end of the turbine hall and an M-G set outside against the Dam face.
The Pepco Benning Road power station in Washington, D.C., supplied 25 MVA of 25 Hz power via a rotary frequency changer in the hall nearest the Metro tracks from 1935 until 1986.
A traction network or traction power network is an electricity grid for the supply of electrified rail networks. The installation of a separate traction network generally is done only if the railway in question uses alternating current (AC) with a frequency lower than that of the national grid, such as in Germany, Austria and Switzerland.
Transposition pylon of power line for single-phase AC traction current (110 kV, 16.7 Hz) near Bartholomä in Germany.
Pylons in a converter plant