[6] The government decided on a co-ordinated development that included a new station building, and after an agreement in 1922 between the Railways Department and the Wellington Harbour Board, the reclamation of about 68 acres (27 hectares) incorporating a new double-track line, train marshalling areas, goods yards and sheds and using fill from the Tawa Flat Deviation.

The need to review building techniques after the 1931 Hawke's Bay earthquake and the impact of the Depression on finances delayed the government formally committing to the project until June 1933.

21,000 cubic yards of aggregate from the Hutt River with cement from Whangarei were mixed on-site to create the concrete.

The bricks used for the outer cladding were of a special design, with slots to accommodate vertical corrosion–resistant steel rods that reinforced the brickwork and bound it to the structural members.

The main entrance is on the south side via a colonnade of eight 13-metre- [42-foot]-high Doric columns opening into a large booking hall decorated with delicately mottled dados extending to a high vaulted ceiling.

[9] The platforms, designed to accommodate up to 12 carriages, are made of concrete covered with a sealed surface under verandahs held up by railway irons.

A park was created in the forecourt with lawns and paths of paving stones with brick edging arranged in a herringbone pattern.

His management skills, supported by a large team of experienced foremen and a close working relationship with the architect, ensured that construction progressed very smoothly on a project that was very profitable for Fletchers.

Fletchers reduced the cost of the construction steel to £70,000 from an estimated £85,000 by directly importing it rather than purchasing it from local steel merchants, and had it fabricated on-site by Wm Cable Ltd.[12] Progress was rapid, with 1500 of the piles driven by the time the foundation stone was laid on 17 December 1934 by the Duke of Gloucester, an occasion witnessed by an estimated 5,000 people.

[14] In August 1938, to accommodate increasing staff numbers, work commenced on the construction of the section of the Featherston Street Wing removed from the original design to reduce its cost.

A two-storey brick building with a mansard roof containing a social hall and a garage was built in 1937 facing Waterloo Quay to the north of the East wing, at a cost of £15,000.

One of the first Wellington buildings reinforced against earthquakes, the style was Classical Baroque and Jacobean; ornamented in white Oamaru stone with carved cornicles and balustrades and roofed with Marsiette tiles.

The application of a more commercial attitude to the running of the organisation resulted in a large reduction in staff employed at the Wellington railway station.

In 1991, as a result of a major restructuring of the New Zealand Railways Corporation, ownership of the land and buildings was retained by the Railways Corporation while a new organisation known as New Zealand Rail Limited took over rail operations including freight distribution, commuter and long-distance passenger services and the Interisland ferry service.

In 2000, Tranz Rail moved its head office to Auckland but retained space for operational management of the railway network.

This work included a seismic upgrade, restoration and refurbishment, and installation of three new lifts and dedicated access in the southwest corner to the university wing from the concourse.

The ground floor has always provided services for long-distance travellers and local passengers including a restaurant, cafes, a bar, a shoe repair shop, and a dry cleaners.

[3] In the office entrance to the station, a roll of honour lists 450 members of the New Zealand Railways Department who lost their lives in World War I.

The roll was unveiled by Prime Minister William Massey in the Railways Department's head office in Featherston St on 30 April 1922.

The station was used in a 2009 TV advert in the United Kingdom for train ticketing company TheTrainLine, where a large flock of sheep use the facilities.

[22] In May 2014, the station foyer was used by celebrity chef Nigella Lawson to film a commercial for Whittaker's a local chocolate manufacturing firm.

The proposed development included four buildings built north of the current station over the platforms and part of the marshalling yards.

[27] In August 2018, the proposed sale of the building by KiwiRail was stopped by Winston Peters as the Minister of State-Owned Enterprises as "premature".

[29] The Wellington railway yard incorporates marshalling and storage tracks and buildings and a Multiple Unit Depot (MUD) for servicing EMUs.

A rail line under the overhead stadium walkway goes to the container terminal and other freight facilities on the Port wharves, with a level crossing on Aotea Quay.

[31] When a derailed goods wagon[32] near the Interisland terminal damaged both tracks through the yard out of Wellington on 3 July 2019[33] commuter service to the Hutt Valley and Kapiti lines were seriously disrupted for two days.

This includes the electrified lines serving the Wellington and Kapiti urban areas, plus the Wairarapa Connection service to Masterton via the Hutt Valley and the Remutaka Tunnel.