My point being they ceased on the 1972MkI refurbs, which were 3 units - 2 less than the current CLIP progress. It isn't too late at all, when you consider how many more are left, and rising costs. As you say, others have said what they said and put forward a good case to continue, but this forum should be about discussion and debate and I make no apologies for making a suggestion.
Ceasing CLIP is certainly something that *could* be done. The question is at what consequence, how likely that consequence might be, and whether that is considered acceptable.
I think the generally accepted view is that “do nothing and let the fleet continue as is” would probably eventually end up with an untenable level of fleet availability, possibly reaching the point where the Central Line couldn’t deliver a service in anything like its normal form. There are also potential indirect and maybe even direct safety issues to consider with this.
There’s also the accessibility work, which has already dragged on well past 2020. Again, in theory exemptions can be applies or legislation changed, but there are consequences to this.
The other option is to downscale CLIP to the absolute bare minimum, although what that might be, what it would save, and how this would work out, is anyone’s guess.
CLIP has already been value engineered. Really it should have happened many years ago. With no fleet replacement on the horizon my own view is that it would be risky to cancel it, as it would be taking a significant gamble on a uniquely troublesome fleet that has given trouble right through its life almost from day one. None of us has a crystal ball, but LU’s engineers are best placed to determine what is needed to keep the fleet running. What is more unfortunate is that LU’s leadership have allowed this all to drift essentially for decades.
If it wasn’t for the fact that LU have had enough of a challenge replacing the Piccadilly fleet, let alone the Bakerloo fleet which may well see 60 years in service, CLIP probably wouldn’t have happened in the first place and we’d have a replacement fleet on the horizon. Worth remembering when people claim London’s transport infrastructure is gold-plated compared with other places.