The Conservatives are facing pressure to suspend Chris Pincher and launch a formal investigation.
The RMT's comments follow last week's industrial action which caused travel disruption across the UK.
Jordan McSweeney, 29, is accused of murder and remains in custody after appearing at the Old Bailey.
Standards have "plummeted" since last year when many firms went bust, Citizens Advice says.
Actor Matthew Morrison says it is "a privilege" to represent the LGBTQ+ community in the BBC soap.