Steel bars are exposed, wiring runs across the ground like spaghetti, and lift shafts sit empty – but in just five months this building site will be packed with commuters.

In April next year the first major deadline in the £600 million redevelopment of New Street Station is reached when passengers are admitted.

The modern concourse area will be ready to take 140,000 passengers a day.

The old departures board, ticket office and barriers will be closed after 40 years of use – ready for the second phase of construction to begin.

1,000 construction staff are currently working flat out on the £600 million scheme to make sure that the station will be ready.

Network Rail spokesman Ben Herbert said: “It will be like the turn of switch. The old concourse will close and immediately the new one will open.”

The new concourse has been built on the northern-west Navigation Street edge of the station in the area formerly occupied by the multi-storey car park and part of the Pallasades Shopping Centre – now largely demolished.

Some 50,000 tonnes of concrete have already been excavated, including material from the former Stephenson Tower, and they are still only about halfway through the demolition.

With the structures and foundations and services such as electric cables in place, work is now beginning on the fixtures and fittings. Some small patches of floor tiles have been laid and the first passenger information board is already up.

The area has been partially exposed to the elements ready for an atrium to flood the new concourse with daylight not seen in the subterranean station. Breeze block outlines indicate where shops and the new ticket office will be, although passengers may have to wait until nearer 2015 before they enjoy the benefit of the skylight.

The lifts and escalators will be installed within weeks and before the end of the year the first stainless steel panels will be bolted on to the steel framework over Stephenson Street.

Until now New Street has just had two public lifts down to the platforms, leaving wheelchair and pushchair users at considerable inconvenience. This will increase to 15, while the numbers of escalators are set to rise from five at present to 36. Many of these will be up and running from April.

A covered passenger drop off slip road on the Navigation Street side has also been constructed, with a short stay car park for 38 vehicles above – meaning that traffic congestion on Smallbrook Queensway may also ease next year.

Once the old concourse closes, so will the entrance from Smallbrook Queensway, and so a new walkway to Navigation Street is being put in place to guide people around the site.

For the first time since the 1960s passengers will be able to enter and leave the station from the southern Hill Street side.

Mr Herbert said: “The southern entrance will open up that side of the city centre and is crucial to the city council’s plans for regeneration on the south side.

“This is the first time passengers will have been able to enter the station from the south.”

Once complete, the station concourse will provide an open, 24 hours a day, pedestrian route from north to south, building on a historic right of way through the site.

Meanwhile, construction is also well underway on the replacement for the Pallasades, the Grand Central shopping centre and the flagship four-storey John Lewis department store which is set to dominate the south side entrance. Already the concrete cores are in place for this. Projections are that about 1,000 retail jobs will be created by the scheme.