I haven't yet found anything on it in railway media.

What I wonder about is whether a sympathy strike by locomotive drivers is (1) legal, (2) something that happened before.

If signal workers strike, but there is a significant number of non-striking workers (say those aligned with other unions), then after the initial chaos, management has it relatively easy to organise and rely on strikebreakers.

_{*Lunatic*, n.
One whose delusions are out of fashion.}