Rail Industry Focus

Leeds southern station entrance delivery update

During our site visit to Leeds station, Dave Carlyle, Carillion project manager, Penny Gilg, Network Rail scheme project manager, and Alex McDermott, Network Rail project engineer civils, gave RTM an update on the complex Leeds Southern Station Entrance project. David Stevenson reports.

There are probably two words best used to describe the Leeds Southern Station Entrance (LSSE) project: complex and ambitious. The team is building over water, which brings its own safety risks, and the apartment blocks on either side make site access very constrained.

Last year, RTM was told that the project was to be complete by May 2015 – a target that has been missed.

The new entrance is expected to benefit up to 20% of the station’s passengers, but its location has certainly created challenges: obstructions hit in the river when piling; high and fast river flows; and high winds halting tower crane operation.

These have all contributed to a delay in the timescale: completion has been pushed back, with November 2015 being mooted as a new completion date.

The new entrance levels

The new entrance comprises a concourse deck over the River Aire within an eye-catching enclosed building, which is fast starting to take shape. It will be fed by open link bridges, providing access from both banks of the river.

The entrance is made up of three levels: the first level is an extension to the station’s western footbridge over platforms 15, 16 and 17; then there is a mezzanine level; and then the river deck level.

Access to the widened station footbridge is provided by steps, escalators and a lift, providing an upper concourse with customer information screens, ticket vending machines and automated ticket barriers.

Standing close to what will be the extended footbridge, David Carlyle, Carillion project manager, pointed out where the 63m tower crane has had to lift the various steel hoops and trusses for the structure into place – over the top of an apartment block, and mainly during evening possessions.

“We haven’t got another way of getting another hook near the job because on the Granary Wharf side you have a small bridge that can take only around 7.5 tonnes, and is in a built-up area,” said Carlyle.

When winds at the nearby Bridgewater Place get above a certain speed, the team get alerts from Leeds City Council. “But our tower crane also records wind speed,” said Carlyle. “Generally, we have to work the crane at 75% working capacity because it is so close to the station, and public buildings, so we are trying to not overload everything. However, on some sections we have had to get permission from Network Rail to run it at 100% working capacity. We are trying to balance time spent over the line, safety and getting all the work in.”

To support the concourse extension, a new column has been placed on platform 15 on top of the Victorian viaduct, the arches of which have been strengthened.

Alex McDermott, Network Rail project engineer (civils), said that about 100 tonnes of force have been put down through the columns, so the original structure needed strengthening.

“It is one of the most complex projects I’ve worked on,” he said. “We are creating what is effectively a building and engineering project segregated away from the railway, even though it is on the railway. That’s one of the great achievements to protect the public, trains underneath, the overhead lines and the high street environment.”

Penny Gilg, Network Rail scheme project manager, added that the company specifically picked a building contractor, Carillion, because most of the project is a building one.

Piling problems

However, before the superstructure could be built the team had some significant piling work to carry out in the river. They also had to bring the material upriver to the site, from Carillion Rail’s compound and assembly yard about 1km downstream at Water Lane.

“We did have difficulties getting out of the river,” said Carlyle. “Part of it was that we had to get agreement with the Environmental Agency for the method of piling.”

The team opted to use an 18m jack-up barge to provide the working platform for its 26-tonne piling rig and the area to construct two concrete piers, which form the base of the main structure and are topped off with a steel cap, allowing the deck around the new entrance to be bolted onto it.

In total there are 12 900mm-diameter piles on either side, located in-line with the viaduct arches. “They do get slightly further apart,” said Carlyle, “but the first ones up against the viaduct are the ones carrying the main load. It is only since we’ve got to the deck level and were well out of the water that we have had more certainty in the programme. What we’ve also got down below is two trusses that needed to be slid in under the arches to strengthen them.

“The challenge was to get the two trusses in before we went away for the Christmas break. It was achieved. But we had a flash flood coming through where the river came up 1.2m.”

RTM was told that despite working in such a built-up environment, with residents on either side, there have been very few concerns or complaints raised. The public meetings, which had been monthly, are now being held only every two months because interest was relatively low.

“We did make sure everybody got all the information, and the meetings were well advertised,” added Gilg.

Re-writing the standards

Gilg said a key aspect of the construction has been interconnectivity, and that some of the methods used would have raised eyebrows at the beginning had they been suggested in isolation. “But working together, understanding where we were coming from and our commitment to safety, have made it a lot easier relationship,” said Gilg.

Carlyle added that the construction team is always challenging itself and seeing whether some work could be moved from a night possession to a day possession because “it is much easier and safer to do it during the day”.

They have also taken a new approach with the Network Rail standards. “If you look at them [the standards]…in black and white you wouldn’t build the project,” McDermott said. “We haven’t deviated away from the standards, but we are looking at individual items [using] a risk-based approach and saying ‘we could actually do this differently’. We have managed to do things differently to normal by looking at the purpose of certain standards.

“In terms of method of works we’ve not only just involved the local project team but the regional safety group and we’ve done this collaboratively. They’ve been great because they’ve considered what we are trying to do and why we are doing it.”

This is Carlyle’s first major rail project, with his background being mostly in construction. He said the team had to undergo a peer review on the use of the tower crane because it is so close to the station and residential buildings.

“We had to go for a peer review down at London Bridge station because they are using cranes and using zonal arrangements,” he said. “So, again, we had to go and present how we would run our project and we got their support.”

However, despite the delay in delivery, Carlyle added that continuously reviewing the plan and programme has been vitally important.

“Communication, logistics and planning have been key,” he said. “It is such an interesting job: technically difficult and complex.”