I agree with a lot of what you said here. Glasgow City Council's incompetent promotion of Crossrail really makes me angry.
The reason it annoys me though is that I think the City Union Line could be a really useful part of Glasgow's Rail Infrastructure.
- West Street does have the potential to be a very useful interchange, linking Ayrshire and Renfrewshire to the west end.
- A station in the Gorbals would support regeneration in the area and make the Gorbals feel more connected.
- A Glasgow Cross station with low level platforms on the Argyll Line would improve connectivity and assist with regeneration around the Saltmarket area.
However none of this makes any sense as part of an Edinburgh - Ayr cross country service, or by diverting existing trains away from Central station where existing passengers want to go.
As a new local service however it could be really useful and if it created capacity for say a new service to Renfrew & Braehead then people would accept the lack of a connection to Central because of lack of capacity for new services.
A 4tph service from Springburn - Renfrew would be a really useful local link, without any need to try and justify it by running spurious, slow through services from Ayr - Edinburgh. I suspect the main reason these through services are suggested is to try and justify it as a national scheme so Glasgow City Council doesn't have to fund it.