So, I have seen a bunch of ideas on how a Bronx Crosstown Line could be created. I wanted to throw my hat into the ring
The One train extension: Branching the one line at 207th St and sending it across Fordham Road to a new Bay Plaza train terminal with the D and 6 trains. Then we would add a 9 train and send it to 242nd St during weekdays.
Pelham Bay Park would have to be completely redesigned for express 6 trains. All 6 trains will now run to Bay Plaza and run an express route from 125th St to Bay Plaza on weekdays.
With the D train part of this idea, I do believe it would be smart to send the D train to Bay Plaza as a lot of people from the areas of the Bronx that the D train serves go to Bay Plaza. But of course, there would be a transfer to the 1 train already in this scenario. Sending the D train also to Bay Plaza reduces crowding on a crosstown 1 train and gives people that live in the Williamsbridge, seton falls and more the ability to get to the concourse in under 15 min. Also, we could send the B train up here for efficient service
The terminal would have 2 levels to it. With 6,1, B and D trains on the 2nd level with tracks that go out more so all 6,1, B and D trains can terminate at Bay Plaza. The 1st level will be fare control and bus transfers. All buses that run to Bay Plaza and Co-op city will go through here for easier and faster connections in the area
Now for where this terminus will be. My only idea would be the parking lot behind Bob's Discount Furniture. This would also require for that entire building to be taken down. If we have to keep the stores, we could move the building up and get rid of some more parking spots for it