550 trains axed in 24-hour strike today (31st July).
Previous walkouts took place last Saturday and Thursday, and the remaining strikes are scheduled on 4, 11, 18, 31 August and 1 September.
In a statement, the rail company said it was "surprised" the union had decided to call further strikes, "especially at a time when families want to be out and about enjoying the summer holidays".
"We will continue to seek a resolution and work hard to minimise any disruption to our customers."
Ticket-holders get no compensation during train strikes.
Young teenager stabbed in Plymouth
Stalking suspect sought
Plymouth will not delay local elections
'Quarry dust' sparks worries in Kingsteignton
2025 set to smash UK heat records
Man interviewed by council officials amid flag war
