The rail provider, which runs trains across the Snow Hill, Cross City and West Coast Mainlines, has posted details of the service it will be able to provide from Monday, December 19 until Monday, January 2.
It said that there will a normal service with four trains per hour on the Cross City Line, which runs to Lichfield, and two trains an hour on the Birmingham International to Rugeley service and Walsall to Wolverhampton service.
The provider also said there would be planned industrial action by the TSSA union on Wednesday, December 28 and Thursday, December 29 and some services would only run between the hours of 7am and 7pm, including the Snow Hill Lines, which go through Stourbridge and Cradley Heath and the Birmingham to Shrewsbury line.
A spokesman for West Midlands Railway said: "The RMT union have announced industrial action on the following dates: Tuesday, January 3, Wednesday 4, Friday 6 and Saturday, January 7.
"Additionally, the union have announced action short of a strike between Sunday, December 18 and Monday, January 2.
"Additional strike action has been announced by the TSSA union from midday on Wednesday, December 28 until midday on Thursday, December 29.
"The impact of this on timetables will be confirmed as soon as possible.
"Please keep in mind, essential engineering works are also being delivered over Christmas and in early January. Check our engineering calendar for more info.
"Please ensure you check your train times for your entire journey, including your first and last trains if you're travelling during this time."
For more information and to check timetables for rail services, go to shorturl.at/cquS8