RaIl union RMT confirmed today that it has declared a dispute and is preparing an industrial action ballot on Great Western services.
The union is opposing plans to axe guards and catering services on the new Inter City Express trains being supplied by Hitachi.
Members of the Rail, Maritime and Transport (RMT) union at First Great Western began a 24 hours strike at 4am today (Friday March 27th) over a row about the dismissal of a colleague.
The dispute include guards, train drivers and managers in Penzance.
The announcement comes in the same week the rail company was awarded a 42-month extension on its franchise by the Government.
First Great Western is reassuring passengers strike action will not impact its services.
The Department of Transport has announced plans to improve rail services into and out of the south west. It's also announced an extension of the rail franchise for First Great Western until April 2019.
The Government says it'll mean more trains into Devon and Cornwall, faster journeys between Penzance and Paddington and the introduction of 369 new carriages through the roll-out of new hi-tech Intercity Express Programme trains built by Hitachi.
Passengers are being warned there's disruption on First Great Western trains between Exeter St Davids and Plymouth. A person's been hit by a train at Totnes.
Trains may be delayed or cancelled as a result of this incident.
Train services between Plymouth and Totnes are being disrupted while engineers are checking out a problem on the line.
First Great Western are organising replacement buses, but at the moment passengers are having to make their own way between the two stations.
Trains from Totnes to Plymouth are not affected.
It's hoped that the situation will be resolved by midday.
Rail passengers in the South West face travel misery over Christmas because of engineering works.
Services to and from Devon and Cornwall will end earlier on Christmas Eve - and some will be diverted causing long delays.
Passengers are advised to check before they travel.
Rail passengers travelling between the West Country and London Paddington have faced long delays after signalling equipment was damaged near Slough.
Three quarters of the trains running between Plymouth and Paddington were cancelled today.
Trains leaving Plymouth for London have been badly affected by the disruption, which has seen the usual 20 to 25 trains running on the line per hour be reduced to just four per hour.
There's major disruption on First Great Western services between Exeter Central and Exmouth due to signalling problem. All lines are blocked, with delays and cancellations as a result. First Great Western say they have no estimate for when a normal service will resume.