on Tue Apr 10 08:27:11 2012, in response to Re: Middle Track on the Myrtle, posted by subfan on Tue Apr 10 08:05:42 2012.
The original plan was for the Canarsie line to be on an el over Wyckoff Ave, and there would have been some sort of track interchange here, probably similar to Myrtle-Broadway's connection was between the Myrtle and Bway lines. The third track would have seen more use then (for example perhaps a Canarsie train headed express to the Williamsburg Bridge and Downtown, and so forth. Once underground, that need dissipated, and the most they could hope for was a transfer there between the two lines, but the express track became less and less important then. It was really designed for trains to interchange there too, not just passengers.