Despite initial concerns that London’s public transport system may struggle to handle the influx of passengers during the Olympics, problems never materialised in any significant way. That good news, however, does not take into account the Paralympics, which coincide with the end of the school holidays and a further increase to the traffic and public transport passenger numbers.
The coming weeks will show how prepared London’s transit system is, but Green Park is sure to earn a solid grade, having been specifically upgraded to address accessibility concerns. Engineered to be step-free, it is a vital interchange for visitors to the London 2012 Paralympics, connecting Heathrow via the Piccadilly line to the Olympic Park via the Jubilee line.
The upgrade was far more complex than one might think. In fact, its successful realisation by the Transport for London (TfL) project team, including lead designer/engineer Capital Symonds, was recognised as the Rail Station Project of the Year at the 2012 London Transport Awards.
The biggest change is the new ramped entrance on the south side from the park into the ticket hall, which is beneath Piccadilly. The park slopes uphill towards the station and engineers have built a footpath into the station.
On the south side, before the upgrade, a large ventilation shaft jutted onto the footpath. Engineers have remodeled this into two smaller structures and created a brand new lift entrance which supports the green canopy and allows step-free access from the northern entrance. The canopy’s light green colour was chosen by artist John Maine, who was commissioned to help with the design. It matches the rooftop of the famous neighbouring Ritz Hotel.
Below street level, the station has been extended on its eastern edge to provide step-free access from the ticket hall level to the platforms. A new lift has been constructed that takes passengers from station level down 15 metres to the Victoria Line, and then another 10 metres to the Piccadilly Line. Passengers can then use an existing lift to access the Jubilee Line.
The first task in creating this shaft was to divert services. Using an eight-tonne excavator, engineers then sank a 10 metre by six metre shaft 28 metres deep into the London Clay to create a lift shaft.
In order to construct the lift shaft, the team worked around the clock to excavate and spray a concrete lining and ensure the shaft was secure. To reduce the chances of disrupting the guests at the Ritz Hotel next door, as well as other Piccadilly neighbours, the team decided to install an acoustic shed over the top of the site to regulate the noise emitted while tunneling. This provided an additional benefit of regulating the temperature in the working environment, which helped manage the risks associated with working with concrete in low temperatures.
Once the lift shaft had been dug and secured, the team installed two lifts. They were faced with another challenge, however, as there was no space for an intervention point or emergency exit in the shaft. To overcome this, a transfer door between the two lifts in the shaft was installed. This means that if one of the elevators breaks down, doors between the two lifts can open and passengers can be freed.
One of the team’s key areas of focus was managing movement on the other assets such as the escalators, which had to remain running throughout. They installed jacks on one of the escalators, something that had never been done before. The idea was that if there was movement on the escalator as they were working, they could manage it. The team never had to use the jacks, but it was an example of the foresight used to manage potential risks.
The project team is rightly proud of its success. Not only is the station safer and more accessible for all users, but the completion of the project was three months ahead of schedule. Better still, the complete cost came in well below budget at £48 million – a figure that was originally set just shy of £97 million.