The new trains will replace NI's ageing railway fleet

They were supposed to be carrying passengers towards the end of October but a computer glitch means they cannot go into service.

A bug affecting passenger announcements and onboard visual displays has seen the delivery of more new trains from Spain suspended.

Only two of the six new trains delivered so far are nearly ready for service.

Launched in Spain earlier this year, it was hoped that by now passengers would be enjoying the new fast, comfortable travel promised by NIR.

Northern Ireland transport company Translink said the �80m investment was designed to meet the needs of rail travellers over the next 30 years.

A further �30m is expected to be spent on parts and maintenance over the first 15 years of the trains' operation.

The new trains were manufactured by CAF at Zaragoza in northern Spain.

Journey times are set to be cut with the new 90mph trains, which have faster start-up and braking mechanisms.

The silver and blue carriages are air-conditioned, carpeted and fitted with aircraft-style seating for up to 200 passengers per train.

They have CCTV, audio announcements, wheelchair access and toilets for the disabled.