First Great Western (FGW) says it is working on building better trust with its customers after a survey found it was among the worst performing train companies for customer satisfaction.
The study was carried out by rail customer watchdog Passenger Focus.
The watchdog said many passengers did not feel train companies were "on their side" and did not trust them to provide a good day-to-day service.
The firm said it recognised problems and it was working to solve them.
The study looked at trust in the delivery of the day-to-day services, paying attention to five factors:
- Value for money
- Problem resolution
- Helpful staff on trains
- Helpful staff at stations
Southern, First Great Western and Southeastern services were furthest into negative territory, Passenger Focus said.
The watchdog said: "To build greater trust with passengers, it is important not only to deliver a punctual and reliable service but also to build a stronger relationship with passengers, this being based on communicating openly and honestly."
Dan Panes, from First Great Western, said: "We recognise that there is this trust issue that affects not just FGW, but affects the railway as a whole.
"We recognise that it is something that we need to tackle if we want to build the relationship with customers that we want."
FGW carries about 1.5 million passengers every week on 9,000 services and calling at 276 stations.