The junior pilot to hold 757 CA in Mem on bid 16-01 was hired in Jul 2015. He is projected on the current training letter to start CA training in Jun 2018 and activate at the end of Aug 2018. That would be just over 3 years to CA for a 2015 new hire, the folks at the front edge of the current hiring wave.
That training date will probably change with the next bid, but it shouldn't get any further out, but get closer if anything.
That time frame, however will likely not hold true for those getting hired today in the middle or tail end of the current hiring wave, but who knows. In any case, I would guess that 3 years to Captain is probably a record for us, beating the 4-5 year upgrades to 72 CA during the initial postal contract era. Your mileage will surely vary.