Extending the Astoria Line presents issues with eminent domain, and rerouting the interceptor sewer. This avoids that. Extending IBX to just Harlem or just LGA limits your ridership, but this greatly expands ridership.
I can see that the PA-analyzed route would conflict with the sewer, but what about a portal that took over the northbound half of 81st St? It's a very wide road, and it's seemingly fully west of the sewer
The longer I do this, the more tunnels I find. Something that seems obvious suddenly becomes not possible. I was considering an alternative NW extension, but it would likely be more costly. That whole area is just not worth digging up.
Have you also looked into Joint Transit Association’s idea of IBX spurring off NYCR before Jackson Heights station and tunneling to the station for a better connection (which can then be tunneled to LGA)?
Comments
I’m more of an “extend the Astoria Line one stop to Con Ed, get a rail yard for deinterlining, and call it a day” type of guy.