by Jersey_Mike
It would just be a rehab of the existing motor controllers, as they are used in MU service with the older 01500/01600 series cars, which are almost the same as the 01700sSEPTA installed a new backwards compatible IGBT based controller from Vossloh replacing the older GE supplied cam controller system. Retrofitting the entire fleet cost 11 million and the DC motors did not have to be changed. The only side effect was a buzzing noise caused by the chopped current flowing through the dynamic brake grids.