The NR class is basically a light-weight version of the Dash-9, but with fancy control electronics (it can be re-set to three different horsepower ratings: sort of like the Norfolk Southern's C40-9, but more so, I guess!), and I wouldn't even try to guess what that means to how long it takes to load. GE locomotives in general had the reputation of being slow to load, but modifications to the control electronics could make them... less slow or more slow.
82 class has no direct U.S. analogue: the closest would have been an "SD59" (12-710 engine, CC trucks), but that variant was never offered in the U.S. It is also somewhat lighter in weight than a standard U.S. six-axle unit.
(I've taken the liberty of adding more description here in case there are some North American readers who don't know what the model designations of "export" (actually built under license in Australia, with major components imported from N.A.) EMD and GE locomotives mean.)
Part of the weight reduction for the NR class was the decision to use traction motors smaller than the model 752 motors used on domestic GE locomotives with DC motors. Does this have an effect that you have noticed, Dash-7? A domestic (DC motored) GE would be better than a domestic (DC motored) EMD at sustained low-speed lugging: better short-time ratings for the motors. I have heard that this is not so with the Australian variants (sensibly, since the 82 class was bought for coal trains and the NR with interstate merchandise trains more in mind): the GE motor used on the NR class is smaller than the standard EMD motor.
And have you heard any scuttlebut about the Queensland Railway 5000 class? (These, for the non-Australians, are essentially AC44 done up in a carbody more like the NR class: the first GE AC-motored units in Australia, used in the same coal-mining district as the 82 class.)
The rest of you:
Sorry, I just assumed that-- since one can often, as a train passenger, feel a bump going over switches-- the same operating restrictions would apply to them as to diamonds. Once again, I win: by saying something wrong on a forum with well-informed people on it, I have learned!!! Thank you all!