On the converted lines, yes, in the city, no.
Thought so.both.
Extremely tight curves, and overall weight is a lot, although I reacon it could take the axle weight.
Pity there are no Class 01s around.
Thought so.
I think the curves round Market Street are the tightest (Excluding the Eccles line.)
But other than that there's no reason? Physically speaking?
Weight, of course. It's called light rail for a reason :P Don't think that Piccadilly Gardens' road surface could withstand a diesel loco.
Do the Metrolink lines actually have a defined route availability, by the way?