This has been mentioned before.
My only thought it that: How does the gradient on the new underpass compare to the gradients on the Belair line? Are they similar - 1 in 33 or so? And have there ever been issues with 3000's slipping on the Belair line on wet days - things like millipede or leaf litter slippage excluded.
The 3000s have no trouble taking off from stations against a sustained
1/45 slope which goes for many kilometres at a time on the route to Belair, even during the most inclement weather or on the first train of a frosty winter morning. With the assistance of half a Jumbo's worth of power in each car and the dip down into the underpass to get a good run going, the little bump only a few metres tall should be conquered on inertia alone. I'm sure that our gloriously
competent department has already scheduled tests to be conducted in the near future as soon as clearance tests on the underpass are done.
Of all the things that the department has refused to comment on, I think this probably falls into the category of "nobody has commented because it's absurd" rather than "we've got something to hide here."
Cynical old me suggests that they will not reopen the line until electrification is complete.
With the EMUs arriving at a rate of one every two months at the moment (and requiring an indeterminate period of commissioning, trouble-free mileage accumulation, clearance tests and maybe modifications followed by more commissioning runs) it looks like a full service might be able to run some time in 2015-16 if reopening with EMUs (as originally promised a year ago) did happen.
The 3000s will have to do until EMU delivery ramps up, it's either them or the O305 fleet.