The thought of a south connection into LAUS which would allow San Diego to points north of LA trains to continue without reversing direction, among other things has been in the plans for some time. Of course given the usual California bureaucratic system and the pseudo environmentalists screaming dodge every tree, bush, building, and last known habitat of the dry land snail darter, we have thousands of pages of studies and a final proposed alignment that is deadly slow. For more information, the project is called Link Union Station. There is the 1,562 page Final Environmental Impact Statement at
https://media.metro.net/projects_studies/regionalrail/LINKUS_FEIR/LinkUSFinalEIR.pdf or if you don't hate yourself that much you can get most of the worthwhile information and a flavor of what happens in these things in the Project Description;
https://media.metro.net/projects_studies/regionalrail/LINKUS_FEIR/LINKUS_FEIR_02.pdf
Or an even shorter document with plans, but fuzzy ones, and in reproduction, not concept (How can you spend millions on reports and not get clearly reproduced plans in it:
https://media.metro.net/projects_st...inkUSDetailedConstructionPhasingScenarios.pdfAnd if you want to see a discussion that has schedules for all trains into it at the time of the report, there is
https://media.metro.net/projects_st...ixB_LinkUSRailPlanningTechnicalMemorandum.pdfWhen I see these things and their outcome, I feel like shaking some of these people and say, think about what you are trying to do. Buy a few more buildings, make a straighter alignment with larger radius curves and you can double the speed of trains through here. Chances are 20 years from now the whole area will have changed and all the complainers will have moved off to other things to whine about and you will be stuck with your slow speed railroad forever. (Remember, the Roman roads are exactly where they were built 2,000 years ago and entire civilizations have come and gone multiple time since then.)