It's possible that the weight of the passengers could make it worse, considering they would raise the centre of gravity up off the ground, making the train more top-heavy.
Siamsal is correct in his/her assunption, i'm a Tube Train Driver, and there are many variables to take into account.
Where the weight of the passengers just might count, is if the suspension was deflated, but if that was the case, the driver should know about it, (onboard computers) and drive at a reduced speed.
I too drive trains, but the old fashioned type using steam locomotives to haul carriages (yes they do still exist!) We have no such modern devises to sense and suspension changes in the train as described by Lonnie, I suspect Lonnie's reply only refers to trains equiped with air suspension?
However I too fully agree that the weight of the passengers is of neglegable consideration. I have never heard of an enquiry into a derailment where the loaded/unloaded weight of the train was significant factor.