About 4,000 trains will be cancelled daily even after next week’s strikes, with services on some routes cut for almost a month, as operators wrestle with the full impact of the RMT overtime ban. Passengers had already been warned that the railway would grind to a halt next week when thousands of members of the RMT union strike for four days from 13 December. However, it is now being revealed that passengers face very limited services on some routes throughout the festive period due to continued industrial action short of a strike – or an overtime ban – from 18 December to 2 January at the 14 operators where it remains in dispute. The disruption is likely to vary widely between regions and train operators. Chiltern Railways said the ban meant it would run no trains at all on 18 December, the day after the RMT strikes conclude. It also expects to be unable to run any trains north of Banbury on its London-Birmingham network until after the next four days of strikes end on 7 January, meaning a key north-south route will be severed for almost four weeks. The train company said the overtime ban would reduce services significantly throughout the festive period. It added: “The disruption will be substantial, and customers should only travel on our services if absolutely essential.” It is yet to confirm all timetables but will run remaining trains only from 8am to 4pm on 19 and 20 December and warned customers to expect similar service levels to continue. Chiltern Railways said: “The overtime ban in place has put immense pressure on our train maintenance depots. “In particular, it has forced us to close our train maintenance depots on Sunday 18 December, and as such, we will not be able to operate a service on this day. We have exhausted all options, and this is not a decision that has been taken lightly. We apologise to customers for the inconvenience that this will cause.” Network Rail said roughly 20% of the schedule, or 4,000 trains a day, would be cancelled as a result of the overtime ban. The reduced service will lead to busier trains throughout the affected period, which runs between the strike weeks from 18 December until 2 January. Train companies that do not have driver-only operation – the controversial clause that has scuppered a deal between industry and the RMT last week – are likely to be hardest hit by the overtime ban. One of the biggest commuter networks, South Western Railway, which can operate only with guards as well as drivers, has yet to confirm its timetable during the overtime ban. The RMT has called off similar action short of a strike on track, signalling and station operator Network Rail – where the overtime ban was expected to be even more disruptive than the one that will remain in place at train operating companies. The overtime ban will be bookended by two weeks of strikes at Network Rail and the 14 train operating companies. Thousands of RMT members will strike on 13-14 and 16-17 December, causing disruption over six consecutive days in the run-up to Christmas. A further two strikes are scheduled for 3-4 and 6-7 January.