Staff or Agency, a person doing a Supervisors job is expected to carry out the duties of a Supervisor.
Part of the Supervisors job remit is to ensure people are assessed and trained – whether this means they train themselves or ensure others in the team help train, it is generally their responsibility to ensure some training is done.
I always told the Trainees on the courses I did that the majority of people are very happy to answer questions and show how things are done (theres always the odd "Secret Squirrel" who wont tell you anything in case you know as much as him).
Only when you ask the same question for the 4th or 5th time are they likely to get pissed off! Also, dont sit about waiting to be told or shown things, be pro active, even to extreme, to show you wish to learn. If you see a Trainee sitting and reading through the manuals (as opposed to collecting porn or browsing Ebay) you are more inclined to teach him.
If you stand about waiting to be told what to do, the others may think (rightly or wrongly) "lazy bugger why doesnt he do something". Find a job and do it, even if its keeping the workshop tidy, keeping the Killa Spray bottles topped up, follow the Sub Eng (if your lucky enough to have one!)