Crossrail - Creating a Lasting Legacy: Part 3
Images coutesy of Crossrail. © Crossrail.
One of the more complex stakeholder interfaces throughout the project was with London Underground (LU). The new Crossrail tunnels weave very close to – and also cross – a number of LU lines. What’s more, five of the new central section stations are directly connected to existing LU stations. In 2009, a formal agreement with LU was put in place which governed and brought clarity to the complex relationship between Crossrail and LU. The interfaces involved everything from protecting LU’s assets during tunnelling and heavy underground civils work – and managing those works that required disruptive possessions of LU services – to integrating stations operations rooms at the five central stations.
Crossrail: Building Information Modelling (BIM) render showing utilities beneath Liverpool Street station.
Testing was carried out on integrated systems within the new stations, along with short circuit testing to ensure no adverse impact of Crossrail’s 25kV systems on LU’s assets. Crossrail’s contractors also trained LU staff at each of the new stations, and ultimately outlined a clear process for progressive handover of the stations once work was complete, which included final assurance documentation.
This strategy of setting out clear agreements from the outset was applied to every stakeholder relationship – from LU to Thames Water and National Grid. But Crossrail also placed equal emphasis on its relationship with the wider London community.
The value of community engagement
While every effort was made to minimise the impact of construction for the people and businesses of London, disruption was inevitable. Right from the start, Bechtel worked with Crossrail to develop community relations plans for each of the eight London boroughs affected by the central Crossrail works. Since each borough was impacted in different ways, every plan was different.
For Bill Tucker, Principal Vice President at Bechtel and Delivery Director for Crossrail’s central section (pictured left with Camilla Barrow - L and Catherine Metcalf - R) , the outcome of these plans brought home the importance of actively and openly engaging with communities. “When we needed favours and had to make exceptions to our environmental permits – such as completing large concrete pours or making large deliveries at night – our engagement meant we had the goodwill from those communities to continue working,” he explains. “Understanding the value of an effective community relations plan was a big lesson.”
The stats give a sense of the scale of this aspect of the project. In all, over 2.5 million cubic metres of concrete were poured – enough to fill 1,000 Olympic-sized pools. And the project team peaked at about 14,000 people, working over 1 million man hours over a four-week period.
Bear in mind these numbers only apply to the central London part of the project. At the same time that the TBMs were boring underground, major works were also taking place up above, both east and west of the city. These were no less ambitious or challenging.
Making room above ground
About three-quarters of the Crossrail route runs above ground on the existing rail network. In order to accommodate the new Elizabeth Line trains and the increased volume of passengers, Crossrail needed to make significant enhancements to the infrastructure across the Anglia, Southern and Western routes. In all, over 40 miles (64km) of track had to be upgraded and 27 stations remodelled. Plus, around 12 miles of Overhead Line Equipment (OLE) had to be installed and commissioned, involving 1600 new OLE masts.
This work was executed with carefully planned and critical infrastructure commissionings across the route, including upgrades of both Abbey Wood and Reading stations, and the introduction of the Acton Dive-under and Stockley Flyover.
Aerial view of Stockley Flyover.
Network Rail (NR) was contracted by Crossrail to carry out the works. Bechtel worked with them as the delivery partner, as part of a fully integrated team. According to Darren Coleman, Bechtel’s Project Director for the Crossrail surface works, this arrangement worked exceptionally well, due to the collaborative working environment the team developed over years. “Bechtel used NR’s procedures and processes” he explains. “Over the course of the project, we successfully introduced sound project processes that were not originally part of the NR suite of control tools, but which have now started to be recognised as best practice within the Western & Wales region of Network Rail.” These practices have now become embedded within NR and are starting to appear in other projects across the region.
The collaborative spirit and shared expertise of the combined team would be brought to bear over the course of the Crossrail surface works.
One of the key challenges for the team was updating the signalling systems. At the project outset, these were life-expired – in other words outdated – with limited functionality and nowhere near the necessary capacity for the remodelled railway. Crossrail had to integrate new signalling assets (Smartlock, Westlock, ETCS and Axle Counters), both with the existing train protection system and the new central tunnel section’s works.
If that sounds relatively simple, consider this: every change in infrastructure layout necessitated an upgrade to the signalling data – and designing these data upgrades takes at least 12 months to produce. This meant that even just one missed stage of commissioning could delay the project by one, possibly even two, years.
Here’s where Bechtel’s experience in programme management came into play. Simply put, it was pivotal to maintaining the design programme – ensuring every commissioning milestone was reached, with planned infrastructure built and integrated as per the original design and in accordance with the signalling data changes being implemented.
Two major projects built side-by-side
Besides track and station upgrades, the team also had to contend with two huge civil engineering projects, built simultaneously over four years.
Stockley Flyover was built at the junction to Heathrow to improve capacity and increase performance by eliminating conflicting train movements. Its 1,000-ton bridge is 120 metres long and the whole structure stretches to more than a mile. Acton Dive-under was designed to allow Paddington-bound passenger trains to travel underneath exiting freight trains without delays. Before this could even be built, engineers had to move the local aggregates yard – the largest in London – 25 metres north to accommodate the new structure.
Working on an operational railway
What made the surface works so challenging was that all of these major upgrades – including the track enhancements, platform and signalling upgrades – had to take place on an operational railway. These are very busy routes, with passengers coming and going from Heathrow Airport in the West and London City Airport in the East, plus millions of commuters travelling in and out of London each day.
Infrastructure changes had to be delivered in 5-7 hour midweek possessions, 29-52 hour weekend possessions, 4-day all line blocks and 10-day blockades at Christmas. The rest of the time, trains continued running as normal. Besides the challenge of a strict timeline, this also made managing the workforce tricky. To supplement the core resource, suppliers were pulled in from across the UK for each stint of work. Between times, Bechtel had to re-allocate those suppliers in other areas for the build’s duration.
All of this meant that each stage of the surface works had to be meticulously planned from the very beginning, and carried out on schedule within the limited time windows. Each data change had to be done in series – so missing one wasn’t an option. The signalling systems also needed to integrate with the central London systems at three interface points. To enable this, both the central London and surface works had to keep to an aligned programme.
In other words, the team had to work to a relentless critical path for six years in order to deliver the programme. And that’s exactly what it did. Final commissioning took place on schedule over Christmas 2017 and was the largest data commissioning NR had ever undertaken.
Keeping to schedule
Watch a timelapse of the Caversham Bridge Construction.
What was it that helped the team ensure it kept to this strict schedule? In a nutshell, knowledge and experience. Bechtel provided the Engineering, Procurement and Construction (EPC) experience required to manage the integrated works programme across the Tier 1 suppliers on each route. What’s more, NR already had a Delivering Work Within Possession (DWWP) standard which was developed by Bechtel during Bechtel’s involvement with NR’s integrated team on the West Coast Route Modernisation project. On Crossrail, David Bartlett, Senior Programme Manager at Bechtel, developed guidance for work planning in DWWP – the Integrated Work, Resource and Access Plan. Recognised as best practice by NR, the plan provides guidance for all work planning on Crossrail. It helps manage logistics and execution, to ensure contingency plans and risk mitigation procedures are in place. This proved invaluable on the Crossrail project.
To ensure the programme stayed aligned with the central London section works, the teams made regular configuration management plans. These ensured that key outputs were successfully met at key dates.
The teams also made it a priority to fully engage their contractors to make sure the project kept to plan. As Darren explains, “We went through testing times but, working with our contractors, we built an excellent collaborative working environment that enabled problem-solving and upfront resolution of issues to maintain both the programme and the plan.”