Basil Jet wrote:
Some butterfly valve has failed, and it's a recurring failure, happening
half a dozen times in the last three years according to the union reps,
or two or three times according to the management. Large numbers of
drivers are refusing to drive the trains and managers are being called
in on their rest days to handle the crisis. The valve is rumoured to be
connected with the doors. There's no mention of this on TfL's site.

Presumably that's the reason the Picc is part-suspended this evening, "due
to a temporary shortage of train operators"?

Do you know what's the consequence of the butterfly valve failing?