Sure. But the annual timetable change is on 11 December and the new timetables will probably be published in the course of October, depending on country and company.

For a better answer you will need to be more specific than that, at least which countries and what dates you wish to travel on.

Some countries run nothing at all on Christmas day and limited services on the 26th as well as services ending earlier than normal on the 24th.

In the UK for instance the quiet Christmas period is often used for extensive line works so there can often be very disrupted services through the Christmas - New Year period.

On Xmas day itself-mostly Scandinavia + UK have no trains or so little local only, that you cannot travel. The major countries in the middle of EUR surely do have trains as on normal sundays. In many other countries the even befroe 25/12 is in fact the more importtt day and anything-not just trains-comes to a complete standstill

The holidays around Xmas are usually 2 weeks for most and trains do run-everywhere-maybe at reduced schedule.

Also on 31/12 in the late afternoon or evening in many countries service is severly reduced or installed.