People catching the train in parts of the West Country are likely to face disruption at the start of a five day strike by the RMT Union.
South Western Railway services between Yeovil Junction and Westbury via Frome will be cancelled and no SWR trains will run on the Bristol Temple Meads to Salisbury route.
The route between Exeter St Davids and London Waterloo via Salisbury will also be affected by today's walkouts.
The strikes are part of the long-running dispute over planned changes to the role of guards on trains.
In February, the union suspended industrial action when it seemed like a resolution was in sight, however the RMT claim the train company has been "dragging its heels" in talks over the past few months.
The company said it met with the union last week and agreed to arrange new dates to continue those talks.
SWR is strongly advising passengers to plan their journeys in advance.