My friend lives out near Rockaway Av on the (3) and he said something about late nights he sees R-142 (3) trains everyonce in a while.I believe him but late nights lots of things happen unexpectedly due to G.O's the (3) may not have yard access so a (5) or (2) may be used for the (3) or even the (4).
A few months ago there was an emergency G.O they ran 32 (D)'s due to trackwork.(C)'s were re-routed via Concourse to Tremont and turned heading back downtown.It was a 1 night thing though.