The problems are compounded as many of the trains and non-striking crew are redistributed and are not where they would normally be.
Eight days of strikes have been planned – the biggest walkout to date in the long-running dispute, hitting the festive period and the start of the New Year. A spokesperson for the Rail Delivery Group said: “With time running out to avert the widespread Christmas disruption which would result from further industrial action, we need the RMT to call off the strikes and work with us to reach a fair deal for our people, our passengers and for the taxpayer.”