UK rail strikes: what is happening?

Biggest stoppages in decades involving 40,000 Network Rail staff could spread across public sector

• This explainer originally appeared in the Guardian's First Edition newsletter. Sign up here.

After last-minute talks to avert them failed on Monday, the rail strikes that got under way this morning will be the biggest in the UK for more than 30 years. (Here's how the Guardian covered the last one, which ended with an 8.8% pay rise for rail workers.) As well as the 24-hour walkouts by members of the RMT union - happening on Tuesday, Thursday and Saturday - a separate London Underground strike is happening in the capital on Tuesday.