- - - Challenges Personnel needed a reliable, portable instrument to accurately measure and record the current on each feeder over a selected time period. - Overview The Southeastern Pennsylvania Transportation Authority (SEPTA) operates the transit system throughout the city of Philadelphia, extending into the surrounding counties in Pennsylvania and across the Delaware River into New Jersey. A major component of this system is the network of subways and commuter trains. Power for the operation of these trains is provided by an array of substations distributed throughout the region. One [...]