KiwiRail has reduced its evening peak services on the Paraparaumu line between Wellington and the Kapiti Coast to allow for upgrade work.
Trains are now scheduled to run every half-hour between 3pm and 7.30pm from now until Christmas Eve. Morning peak-time services are unchanged, although there may be delays.
KiwiRail spokesperson Deborah Hume says the new timetable allows for upgrade work on the section of track between Pukerua Bay and Paekakariki.
She says all trains will have six carriages, which will boost the capacity of some services.
The Upper Hutt, Melling, Johnsonville and Wairarapa services are unaffected.