Most of the operators have only announced their plans today-
On the main line operators most have no scheduled changes although warning of a possible small number of cancellations each day- except for no Night Riviera Sleeper to Penzance.
The more significant disruption, although still limited, is on London commuter operations-
South Western trains including the Isle of Wight- https://www.southwesternrailway.com/plan-my-journey/industrial-action
No Gatwick Express
Southern, Thameslink and Great Northern- https://www.thameslinkrailway.com/travel-information/plan-your-journey/industrial-action
South Eastern, also London North Western, West Midlands Trains, Northern Trains, C2C and Greater Anglia- no expected changes
Chiltern- https://www.chilternrailways.co.uk/strike