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.
The Bodmin and Wenford railway took delivery of a new engine today, whose working life was spent in the China clay pits around St Austell.
Denise, as she is known, is in need of a little bid of TLC - but there's no shortage of volunteers ready to restore her to her former glory, as John Andrews found out.
The severe winter storms took their toll on train punctuality including that of CrossCountry last month, according to official figures.
The CrossCountry train company, managed only a punctuality figure of 78.1% in February, compared with 88.8% for February 2013.
First Great Western, affected by the severe damage to the coastal track at Dawlish in Devon, had a trains-on-time figure of only 80.4% last month, compared with 91.8% in February 2013.
Since December staff dealt with more than 500 fallen trees blocking lines, 285 flooded sites and 73 landslips or line washouts.
There's widespread disruption to rail services in the West Country owing to flooding. There are currently no services running between St Ives and St Erth. Replacement bus services are being laid on. There are also no services between Penzance and St Erth. Tickets are being accepted on bus routes.
And there are no trains between Exeter St Davids and Plymouth owing to high tides affecting the line from Exeter to Newton Abbot.
Problems on the trains this morning. There are currently no services between Penzance and St Erth. And services between Liskeard and Looe have been replaced by buses.
First Great Western has suspended all of its services between Exeter St Davids and Barnstaple due to the earlier flooding.
A replacement bus service is being arranged.
The train operator does not know when normal service will resume.
There's disruption on First Great Western line between London Paddington and Swindon, London Paddington and Oxford, and between London Paddington and Taunton due to person hit by a train at Hanwell. Trains in and out of Paddington may be delayed or cancelled.
There's one lane closed on the M5 Northbound between junction 22 (A38 / B3140 Burnham-On-Sea) and junction 21 (A370 / B3440 Weston-Super-Mare).