Drivers on South West Trains (SWT) are to stage three 24-hour strikes following a row over taxi benefits.
Strikes were previously held by Waterloo-based drivers
The union Aslef said on Friday its members would walk out on 29 August and 8 and 11 September.
A spokesman for SWT said they were "disappointed" at the decision. A number of trains on the London and south network will not be running.
It follows SWT's drafting in of managers to drive trains during previous strikes in July and August.
Aslef members carried out a series of Waterloo-based strikes in July and August, after a row over a SWT move requiring train drivers to pay tax on the firm's out-of-hours funded taxis.
When the company drafted in managers to drive trains, Aslef claimed safety was compromised, a charge strongly denied by the company.
SWT defended the decision, saying: "What the union sees as strike breaking, we see as customer service."
A spokesman said: "We are disappointed that strike action has been called.
"Less than half of those eligible to vote actually voted in favour of strike action."
SWT warned of severe disruption in the midnight to midnight strikes.
SWT operates commuter routes from Waterloo to the south west and south east, including Bristol, Plymouth, Reading, Weymouth and Brighton.