Original sentence: A Solid state Auxilliary Converter provides 110v DC and 240v AC supplies; this is the source of the loud buzzing noise which can be heard when the train is stationary.Despite the differences though, the units can be used interchangably
Edited sentence: A Solid state Auxiliary Converter provides 110v DC and 240v AC supplies; this is the source of the loud buzzing noise which can be heard when the train is stationary.Despite the differences though, the units can be used interchangeably