There is very little "grind and whir" when starting a properly maintained electric motor/gear set. If the gear mesh is correct, and everything is properly lubed, it's almost silent. Most of the gear noise in model locomotives is due to poor mesh, which in turn is due partly to our refusal to pay the price of exact tolerances, and partly to the fact that a stationary motor geared to a pivoting axle can't be kept in proper alignment. One COULD build a precise gear train for a model, but the tolerances would have to be scaled down along with everything else, and very few people could afford the result...
The Milwaukee greased their pantograph contact areas, so even wire noise wasn't loud.