It was also pointed out in one publication that, in theory, the REPs could be coupled and run in multiple with any of the other SR EP units but, in practice, if this was done they would have blown every circuit-breaker in the vicinity!
Somewhere in my bookshelves there is a recorded run with a 4REP + 4TC combination that (it is claimed) reached just over 106 mph, although this was quite unofficial. Since the officially recorded maximum for a third rail unit is (or, at the very least, was until recently) 106-point-something with a class 442, which also used the electrical gear from the REPs, that speed claim could quite possibly be legitimate.
Whatever the truth, for such "uninspiring" units (as much of the press referred to them) they had the all the makings for the stuff of legends!