Pembrokeshire deserves a better rail service, says local AM Paul Davies.
First Great Western, which operates the main line trains from London to West Wales, has just come last in a passenger satisfaction league table.
The independent rail consumer watchdog Passenger Focus sampled 50,000 people in its National Passenger Survey.
Only 74% of First Great Western's passengers were satisfied with their journeys compared to a national average of 81%.
"Time and again I hear about trains running late and even being cancelled between London and Pembrokeshire," said Mr Davies.
"Being at the end of the line means it's a long journey for anyone from our county and this adds problems in terms of missed connections when trains run late."
And even when passengers do get to Pembrokeshire there can be further transport problems.
"We heard just last week about Ben Large who travels by Arriva trains between Kilgetty and Pembroke for work every day. Five times in 14 weeks the train simply failed to arrive. It's just not good enough," added Mr Davies.