Most Healy Mills drivers would crack open the controller to notch 2 then notch up one stage at a time but acceleration was sooooooooooooo sloooooooooowwwwwwwwwwwww. "Your" method certainly got 'em moving but needed an eagle eye on the ammeter. When overloaded, the Type 4s always made a curious groaning noise, as though in pain.
As you've gathered, HM was a freight depot. When one of theirs was on passenger duties for the first two or three accelerations, they would go like a bat out of hell up to 50mph or so then stick, because the contactors had worn tracks in the copper with a ridge at the end. Eventually, the ridge would break down to the point when the contactor could pass it, then at least two stages of field weakening would kick in, with an associated lurch forwards. After this, no more problems but moans on freight duties about "formula one cars" on the coal trains!
Happy days....
