@eps200 The link that should have happened, but didn't because of 80s Anti Rail policies was the link south of Central into Wapping Tunnel, to emerge just south of Edge Hill. When studying in the 70s, all the PTEs sent me their plans except Murkeyside. But I have followed Merseyside and through connections having made the acquaintance of both Neil Scales and Mark Dowd. The DfT have been really remiss at not promoting small extensions. Those 508s they've just scrapped would have fitted the bill, and Merseyside paid for them once.
So next time you are on a train going south from Central, look out of the window and you should see where provision was made for the link west. The problem of Ormskirk and Kirkby trains terminating at Central could have been eliminated. Also there is a disused station under Parliament Street, that needs restoring.