TIME FOR CHANGE: The new system is expected to be in place by 2020.

Timetables will be thrown out the window in a radical revamp proposed for Wellington’s rush-hour rail service.

More trains to the city would depart directly from hubs in Porirua, Johnsonville and Taita every morning, and commuters living further afield would travel express into the city from those points. The same system would operate in reverse each evening.

Timetabled rush-hour services would be discarded for a "clockface" system, with trains departing from the hubs at regular intervals.

Four services an hour are planned to depart from Porirua and Johnsonville between 7am and 9am, and five an hour from Taita, though that number could double depending on demand.

The system, proposed by Greater Wellington Regional Council, would be in place by 2020 and would largely be funded by a reorganisation of existing resources, with $49 million of new capital spending required above the existing $1.2 billion 10-year rail budget.

Thirty-five new Matangi trains would be in service by 2016 and would make the increased services possible, Metlink rail manager Angus Gabara said.

A third platform would need to be built at Porirua, and a second track laid between Trentham and Upper Hutt. Improvements are also planned for Upper Hutt and Plimmerton stations, and for the park and ride car parks on the Kapiti and Hutt Valley lines.

The New Zealand Transport Agency would be asked to cover 60 per cent of the cost, as it usually did for transport projects, Mr Gabara said.

Unless rush-hour trains were overhauled, there would be 2700-seat shortages each morning by 2016, regional councillors were told at a meeting yesterday.

The "Rail Scenario 1" plan would increase peak capacity by 53 per cent. Councillors voted to include the overhaul in a regional public transport plan that would be submitted for public consultation in April.

The losers from the scheme would be the 1 per cent of rush-hour commuters who needed to travel from the "outer circle" beyond Porirua and Taita to a station in the ‘‘inner circle’’ before Wellington, Mr Gabara said.

Those passengers would need to change trains to reach their destinations, because outer circle services would go straight to Wellington.

"No doubt they’ll be the people who are up in arms, and that’s what the consultation is all about."

Equally, a passenger boarding at Waikanae would not be able to get off at Porirua but would have to change at Plimmerton to reach Porirua.

Services from Waikanae or Upper Hutt were often full by the time they reached the population hubs of Porirua and Taita – a frustration the new scheme was designed to eliminate, Gabara said.

He added that commuters departing from Porirua and Taita would no longer be offered an express service into the city, but all-stops services from those hubs were already fast, comparable with a car journey.