A glitch in the new State Rail online booking system is not allowing pensioners to select the 'day excursion' option for coach services.

Pensioners in the Western Plains area have been using the day excursion option, for example, to travel to appointments in Dubbo at the cost of $2.50 return. 

The removal of the option makes them have to pay for both forward and return trips without prior notice, rather than being able to take advantage of the within-one-day cap available throughout the state. 

"I noticed the change on Tuesday when I attempted to book a seat via the State Rail booking site", Coonamble resident Dave Backbeach said.

"I cancelled it all and called a State Rail booking phone agency. They were also unaware that there was even a new booking system, far less changes."

A Transport NSW spokesperson said they are still working on fixing the error but in the meantime, any customers who have been overcharged can contact the NSW TrainLink call centre at 132 232 from 7am to 10pm any day.