Train passengers in Chichester have been urged to plan ahead of a major rail closure later this year.
A multi-million pound upgrade will see the West Coastway line shut during this October and November.
The work will affect the route between Barnham, Chichester and Havant.
The section will closed for nine days over the autumn half-term holiday from October 26 to November 3 and the following three weekends.
This is to allow Network Rail to lay 2.3km of new track and replace outdated equipment at Basin Road, Stockbridge Road, Brook Lane and Bosham level crossings with new and more reliable technology.
This will improve journeys for passengers and motorists who drive over the crossings. Work will also take place at stations on that section of the route.
Trevor Tupper, secretary of the West Sussex Rail Users Association, said: “I know the schools and college around Chichester are aware of this.
“There is never a good time to do this type of work but a half-term holiday is as good as any. Most of the passengers in the week coming from the west are students, though there are some commuters, of course.
“If Southern do what they did when the Brighton to Three Bridges line was closed during the February half-term, with a fleet of buses, I don’t think there will be too much of a problem. The real problem will be at weekends because Chichester will lose all its trains then for three weekends.
“But, even then, if Southern do what they do for the usual weekend closures, with fast and slow buses to Portsmouth, passengers should not have more than 20 minutes added to their journeys.”
The closures will begin on October 26 and 27 with the line between Barnham and Havant. On weekdays from October 28 to November 1, buses will replace trains from Chichester to Havant.
The Barnham-Havant line will be closed again on the following days: November 2 and 3, November 10 and 17 and November 30 and December 1.
John Halsall, Network Rail’s south east route managing director, said the work would add to the more than £100m it had invested in the south coast railway in the past year.
“Passengers will still be able to travel to London, Brighton or Portsmouth, but may need to use a replacement bus and journeys will take longer.
“Following on from the successful Three Bridges to Brighton blockade, we will work closely with our colleagues at GTR (Southern) to put passengers first, ensuring people are fully aware of the impact on their journey and the alternative options available to them,” he said.
GTR’s infrastructure director, Keith Jupps, said: “An alternative rail replacement bus service will be in place and we’ll ensure that passengers are kept up to date with the options available to them.”
Bognor Regis trains will continue to run during the work and Chichester will keep its London service on weekdays.