on Sat Aug 24 02:22:34 2019, in response to Re: Lower Level platform 42nd & 8th Ave., posted by murray1575 on Fri Aug 23 17:03:17 2019.
I donít think the 60 St route was an afterthought but its current configuration is a modification of what was originally planned. Originally, the line was supposed to use the Queensboro Br to get to Queens probably using the trolley tracks. In Manhattan the eastbound tk would run under 59 St and the westbound tk would run under 60 St as it does now. At some point, it was decided to build an east river tunnel instead and construction under 59 St was abandoned. There were supposedly remnants of tunnel construction under 59 St between the IRT upper and lowere levels but these were destroyed when the 59 St exp platform was built.