The reason they don't do that is because Queens riders want 49th Street, So Broadway Local service is what's demanded for Astoria.
The problem is that means yard access becomes an issue. Here's how I'd do it:
- Astoria-Coney Island, via Broadway Local/Brighton Local.(stops at Dekalb on the current platform).
-unchanged. This would cause a weekday only choke point at Dekalb. It could also be suspended, but that won't go over well.
-unchanged
-96th St-Coney Is via Broadway Express/4th Ave Express/Sea Beach.
-becomes a local to Forest Hills.
stays on 53rd, to 63rd.
-Jamaica Center-Bay Ridge, via. QBL Express/63rd St/Broadway Express/Bridge/4th Ave Local (stops at Dekalb on the current platform)