There was a little old woman among the slaves called Sarah, who was nearly past work; and, Master Dickey being the overseer of the slaves just then, this poor creature, who was subject to several bodily infirmities, and was not quite right in her head, did not wheel the barrow fast enough to please him.
The above paragraph is from 'The History of Mary Prince'
I just presume 'past work' means she is too old to work, but I am not very sure.
Many thanks in advance.