Nearly half Wellington's 12 new Matangi trains that have been withdrawn from service after an electrical fault was detected in one of the units on Tuesday.
A similar fault in the auxiliary power system was found in another unit a few weeks ago.
Chair of the Wellington Regional Council Fran Wilde says that, for safety reasons, all of the new trains that were cleared for service will be taken out of operation until the fault is fixed.
KiwiRail expects all of its Wellington services to run on time and says it hopes to have the problem fixed this week.
It says, in the meantime, shorter trains will operate on the Upper Hutt and and Waikanae lines and passengers may experience more crowding on these services.
