"A " train Rockaway Blvd connection to ex LIRR

I'm curious if there are any pictures of the construction of the connection to the ex LIRR Rockaway Beach line. It looks like the track to Lefferts was starting to rise up over the LIRR so it was a logical place to cut the express middle track and squeeze the new construction line in to connect to the LIRR. Is that a correct assumption? I tried looking online but all I didnt get the results I was searching for.

http://www.nycsubway.org/perl/show?75542


http://www.nycsubway.org/perl/show?76016


http://www.nycsubway.org/perl/show?75551

Thank you for the pic link. I was allways wondering how they did the construction without affecting service.