Would EP in this context be Electro Pneumatic - like the control system on railway locomotives?
Yes, that is what EP stands for in this case. I'm not familiar with railway control gear, but with trams the controller in the cab is basically a remote control with all of the switches and contactors housed elsewhere - under the stairs on double deckers, and I believe in the roof tower on Leeds 601. It uses air to change those as required. A very rudimentary description but I confess I'm not that up on it myself!
VAMBAC stands for Variable Automatic Multinotch Braking and Acceleration Control - in this case a lever in the cab controls a large drum full of contactors in the tower with all braking and acceleration controlled electrically. As well as being used experimentally on 602 it was also used in production on Blackpool's Coronation cars (of which 304 survives in Blackpool, currently out of service) and the rebuilt Marton VAMBAC trams, of which 11 is in happy preservation at the East Anglian Transport Museum. Indeed, Channel 4's 'Salvage Squad' programme covered the restoration of Coronation 304 and there is a fuller explanation of the VAMBAC gear in there (
First part).
Incidentally all three were preserved, but 601 was vandalised at the Middleton Railway. 600 is at Clay Cross and 602 at Crich where it sees occasional use.
602 hasn't been used for nearly ten years now, and is extremely unlikely to see use again without a major overhaul. The VAMBAC equipment was notoriously unreliable in service and in preservation (often losing all power - meaning no brakes!) and this, coupled with other defects, has led to the car's withdrawal. As mentioned above, though 11 is fully operational at the EATM with a fully overhauled VAMBAC system - it's said to work better now than it did in service!
601 was actually one of the few trams at Middleton to not get vandalised! It was, instead - and perhaps even more tragically - ravaged by a fire believed to have been caused by a stray cigarette from a visiting enthusiast, although of course it's unlikely that the 'real' reason will ever be known.
600 is indeed in the TMS' store at Clay Cross. It does have 'traditional' controllers (I can't remember the exact type off the top of my head, it's been a couple of years since I was at Clay Cross) and in fact originally hails from Sunderland, where it was numbered 85 and also an experimental vehicle. It moved to Clay Cross in 2005 and, again, is expected to stay there for the foreseeable future having no place in the Museum's current operational fleet as well as numerous defects. The interior is also still in excellent, as-withdrawn condition and there is an argument for preserving and conserving it as-is, rather than restoring the tram.
HTH.
