Complex sentence: The R won't be extended to Midtown Manhattan as there is not a good location to turn trains there, and it won't be extended to Queens because of conflicts with maintenance work and a high cost for minimal rider benefits.
Split into simpler sentences: The R won't be extended to Midtown Manhattan as there is not a good location to turn trains there. It also won't be extended to Queens because of conflicts with maintenance work and a high cost for minimal rider benefits.