The loop wye that has been added with the "close connection" option (along the 101) is probably to allow the current train storage, south of Mission Tower, to connect and "stage" trains, either direction.

The original work I was first involved with beginning back in 1993 was only for 6 through tracks, over the years, ML added the "staging" yard, and the current "final" plan is now for a 9 track run-through, with a tighter "loop" configuration (the earliest work looked at coming in from the LOSSAN south only, and would have tied in further south, after a flyover of the Metro subway yards below old First Street) with the wye to allow for movements north bound along the River. The wye option allows for greater flexibility in access. Today, an accident in the throat could potentially shut down all access, the wye would allow for access and egress to most of the ML lines, from both directions.

Yes, these things take far too long to do today. We've been wasting 10 minutes per train now every single day for over 25 years, which has wasted millions every year, in operating costs, and added travel time costs of ten minutes lost every day for the last 25 years to millions of user trips on LOSSAN and ML....

Those "savings" (now, lost forever, due to our indecisive and slow motion "study it to death" inept and inefficient planning processes) would have paid for a whole lot more rail service to places like Perris. And, would have brought us much closer to Max's every "10 minute" LOSSAN service delivery, like they operate in his hometown, between Zurich and Basel. We also have about five times the population density (Sou Cal has over twice the total population of "all" of Switzerland) along the LOSSAN south. And, LA-SD only just a bit farther apart than Zurich-Basel, along the busiest and most congested interstate highway corridor in the US.....