تيار مستمر
Direct current power for the interurban trolleys on the Liberty Bell Line was produced (from AC power supplied by overhead lines from Allentown) by rotary converters at substations in Allentown, Summit Lawn,Coopersburg, Quakertown, Sellersville, Souderton (in the carbarn), Lansdale, and Washington Square. Unlike the notation in the "See Also" section below, LVT never used mercury arc rectifiers.