The answer to this question (and it's a good question) is incredibly nuanced and depends completely on your environment.
When it comes to being productive in research while in training you have to play to the strengths of the program.
First, find out who in the department are the 3 most productive i.e. pumping stuff out AT LEAST annually. A lot of people make the mistake of attaching themselves to a research mentor who doesn't do research (though often thinks of him or herself as a research person).
These productive people will be able to answer this for you and will get you involved in something that will get published on your timeline if you ask them and do the work.
2nd. Play to the strengths of the program. Don't start a sarcoid project if there is no local registry or interest. Pick low hanging fruit, the project will ALWAYS take more work than you initially anticipated so keep the variables that are in your control as easy as possible.
Picking the right mentor is 99.9% the battle