KiwiRail says the line between Wellington and Wairarapa in the North Island is likely to stay closed throughout the weekend following a major derailment.
Buses have also replaced trains on the TransAlpine Midland line between Christchurch to Greymouth after a washout at Kokiri on the West Coast.
The Wellington to Wairarapa service hit a slip just outside a tunnel at Maymorn near Upper Hutt at 6.17pm on Thursday.
A locomotive and carriage went off the tracks. However, both stayed upright and no one was injured.
Up to 250 passengers were ferried by bus to Masterton after three carriages were pulled to safety by another engine.
Engineers are trying free the locomotive and KiwiRail spokesperson Nigel Parry says the line is likely to stay closed all weekend while the train is recovered and the site cleared.
Mr Parry says bus services will continue to operate on Saturday and Tranz Metro will review the situation on Sunday.
Tranz Metro says it expects its train services on the Wairarapa line will be back to normal by Monday morning.
The Transport Accident Investigation Commission has launched an inquiry into the incident.
Meanwhile, a small slip that stopped trains on the Paraparaumu line is being cleared and Tranz Metro expects trains to resume normal service on Friday evening.
The slip occurred just north of the Ngauranga Gorge. Mr Parry says buses have been transporting passengers between Wellington and Porirua.
Van collides with train
Two people have been injured when a van collided with a work train north of Kaikoura on Friday afternoon.
St John Ambulance says the pair suffered minor to moderate injures and have been taken to hospital.
KiwiRail says the work train involved was made up of two light engines and was heading south to Christchurch.
The line is clear and there will be no delays to the TranzCoastal passenger service.
