Towards the end of the 1950's the PRR was looking for a new electric loco to be used in front of freight trains to replace the less suitable P5a in this role. A few years earlier, the Virginian had purchased the EL-C from GE, which performed well in the Blue Ridge Mountains to pull heavy coal trains. So the PRR ordered a development of the EL-C with similar optics and also an ignitron rectifier from GE. They were built like American diesel locomotives, i.e. with one cab, load-bearing frame and narrower hoods that were accessible via open running boards. The single diamond-shaped pantograph of the predecessor was replaced by two single-arm pantographs. Thanks to new developments in the field of electronics, the output could be increased from 3,300 to 4,400 hp. 

With a starting tractive effort of 96,0000 lbf and a dynamic brake, the locomotives are ideal for heavy freight trains on mountainous routes. The E44s were only used in exceptional cases to pull passenger trains, as they could only go 70 mph and had no boiler for train heating. The last six of the 66 engines were designated E44a because they had an output of 5,000 hp thanks to new diode rectifiers. The manufacturer converted another 22 E44s to the E44a status by 1970.

The reason why the remaining E44s were not converted was the collapse of the PRR, as a result of which all E44s and E44a first went to Penn Central and later to Conrail. At Conrail, the remaining Ignitron rectifiers were replaced with diode technology, with the output remaining unchanged. All engines were shut down in 1981 when Conrail stopped electric operations. They were later sold cheaply to Amtrak and NJ Transit, although NJ Transit found no use for them and gave them to Amtrak. There they spent the time until the mid-nineties in switching service for passenger traffic and were then scrapped.