'Very few' Northern trains on Saturdays in Decemberpublished at 16:58 Greenwich Mean Time 28 November 2018
Northern will run less than a third of its services on Saturdays in the run up to Christmas, with "very few" trains in the evening.
Passengers in the north of England will face major disruption during the latest round of strikes on 8, 15, 22 and 29 December.
One tweeted that the recent service offered by the operator had been "absolutely shambolic".
RMT members are embroiled in a lengthy dispute about train guards.
The Department for Transport (DfT) urged members to call off the "needless" industrial action.
The announcement comes after Transport for the North urged the union and the rail operator to find a solution.