Building Crossrail: A holistic approach to sustainability

27 March 2014


Michael de Silva, BSc, Ph.D., FCIWEM, MIEEM C.WEM, CSci, Crossrail Sustainability Manager, Bechtel Ltd, 
Robert Paris, BSc, MSc, MCIWEM, MIES, Head of Sustainability & Consents, Crossrail Ltd,


At Crossrail, we are passionate, not just about building a new railway but ensuring it is delivered in a way that provides a lasting economic, environmental and social sustainability legacy.  We have enshrined this in our strategy and governance processes and our contractors have joined us on this journey.

This paper provides a comprehensive yet concise account of how Crossrail has organized itself to deliver a sustainable outcome as well as detailing a structure for successful outcomes.

This paper covers four main themes:

  1. Planning for delivering sustainability on a major infrastructure project
  2. Creating a Sustainability Governance Structure to manage sustainability performance
  3. How the use of sustainability assessment methodologies have helped outcomes
  4. Encouraging innovation to deliver better sustainability outcomes

This paper will be of particular interest to client organizations responsible for national infrastructure, but also provides valuable information for designers and construction professionals

What is Crossrail?

At £15 billion, Crossrail is the largest infrastructure project in Europe and forms a major part of the Mayor of London’s Transport Strategy. Crossrail will connect 37 stations, including Heathrow airport and Maidenhead in the west with Canary Wharf, Abbey Wood and Shenfield in the east.  Using the Crossrail service will make travelling in the region easier and quicker, and help to reduce crowding on London’s transport network. Crossrail, as a public transport project, delivers sustainable outcomes by relieving overcrowding on existing underground and train services adding 10 percent extra rail capacity for London and decreasing journey times across London.

The new sub-surface stations will be on a scale larger than that of the Jubilee Line Extension, London, which opened in 1999, connected by new tunnels measuring 21km in length. Around 200 million passengers will travel on Crossrail each year. 

The project will deliver substantial economic benefits to London and across the UK and brings an additional 1.5 million people within 45 minutes commuting distance of London's key business districts.

Crossrail has let some of the largest value contracts in recent UK construction history, providing a much needed boost to UK industry and creating major employment opportunities.  During the construction phase alone, Crossrail will generate thousands of jobs peaking at 55,000.  It will also require the services of regionally based manufacturers and other suppliers.  The estimated benefit of Crossrail to the UK economy is at least £42 billion over a 60 year period. 

Furthermore, the manner in which Crossrail is delivered and the resultant legacy of skills, learning, contribution to UK cultural heritage and good stakeholder relations is vital not only to the delivery of Crossrail but also to the support by statutory authorities and civil society for the delivery of future major projects in London and the UK. In order to ensure that sustainability was built in to business planning, Crossrail produced a Sustainability Strategy.  The strategy has been developed into key sustainability themes that are material to the delivery of the project and then identifies key performance indicators that are used to track performance.

The holistic approach is such that the project takes a balanced view on environmental, social and economic performance. Ownership of different aspects of this performance lies across several directorates across the organization, but is coordinated at a working level by a Sustainability Co-ordination group, and reports regularly to a Sustainability Committee, represented by the senior management team.  A dashboard approach is used to demonstrate performance and an accountability structure is linked to a reward system for good performance.

Whereas many projects have focused on the environmental aspects of sustainability, Crossrail has been particularly successful at addressing issues of supply chain and SME (Small & Medium Enterprise) engagement, supply chain risk management, local employment, skills and training and ensuring that opportunities are not confined to the prosperous south east of England.

The paper will develop these themes and explain how this is being implemented.

Building sustainability into Crossrail and how we do business

In order to ensure that sustainability was built in to business planning, Crossrail produced a Sustainability Strategy.  The Strategy set out a definition of sustainability for Crossrail that is inclusive and far-reaching.  Seven sustainability themes have been adopted reflecting Transport for London’s (TfL) sustainability framework, UK Government priority areas and Department for Transport policy (see diagram below).   The principle of ‘good governance’ is to be applied across all seven themes. The principle of ‘using sound science’ underpins all aspects of the design and construction.

Six of the Crossrail sustainability themes align closely with those for TfL.  The seventh, sustainable consumption and production, reflects that Crossrail is a massive infrastructure project and the use and final disposal of materials is particularly important. 
Crossrail’s Sustainability Themes

Fig 1. Crossrail’s Sustainability Themes and Key Sustainability Initiatives as defined in its Strategy

The Crossrail approach to delivering against these sustainability themes has been to establish 15 Key Sustainability Initiatives (KSI) that are designed to deliver the requirements of each sustainability theme. Fig 1 completes the picture, with the UK sustainable development goals and the Crossrail sustainability themes realised through the KSIs.  In addition, there are three cross-cutting initiatives the undertaking of which is relevant to the delivery of each of the KSIs.

Creating a sustainability governance structure managing sustainability performance

Supplier Assurance Framework coverageSupplier Assurance Framework coverage

Fig 2. Supplier Assurance Framework coverage

Responsibility for the realisation of each of the KSIs has been assigned to senior management under the overall direction of the Chief Executive.  Each Crossrail directorate is then either given or required to identify specific sustainability objectives and targets as part of the annual business plan cascading these into individual objectives as required.  Each year Corporate KPIs are established against which top level management and partner organisations are financially incentivised, of which a large proportion are set to attain a high level of sustainability performance. 

The Committee provides overall sustainability governance, promotes achievement of the sustainability objectives, and supports cross project sustainability initiatives and those responsible for carrying them out, providing oversight, guidance and escalation routes if required.  Every year it reviews the overall sustainability performance to-date and signs off the publication of the Annual Crossrail Sustainability Report, accessible via the Crossrail website

This governance structure and commitment to voluntary annual reporting is quite unique to a temporary organisation.

A supplier performance framework is also being implemented (Fig 2). This is a twice yearly performance assessment of contractors against contract requirements and assessing beyond compliance performance as Added Value and World Class (Fig 3). This is reported to the Crossrail Executive and back to contractors to compare their performance.

Supplier Performance Framework Scores

Fig 3. Supplier Performance Framework Scores

Our sustainability policies and how they drive procurement

Crossrail’s commitment to sustainability is further underpinned by a number of key policies: Environment, Carbon Footprint, Equality & Dignity, Health & Safety, Inclusivity and Whole Life Costing.

Crossrail’s  Procurement Strategy embodies the seven themes of Responsible Procurement1 and these are all articulated within the contracts with our principal contractors who report on performance on a 4-weekly or quarterly basis.

Sustainability requirements have been written into all Crossrail contracts in line with the Themes and KSIs found within the Sustainability Strategy.  Examples of the Crossrail policy requirements that have been cascaded to our Contractors within the works information that forms part of the contractual documentation are included in the list below. Core elements of the works information are taken from the Crossrail Environmental Minimum Requirements (EMR). 

The EMR are standards and procedures that have been agreed with local authorities and statutory agencies in order to control and manage environmental impacts. This includes the Construction Code, which explains how contractors work will be controlled. The Crossrail Construction Code represents best practice environmental management and is widely considered to have “raised the bar” on construction performance requirements in the UK. 

Key elements of delivery are:

  • Environmental requirements are contained within the works information and include a number of minimum performance levels in addition to specific targets. These requirements are extensive and cover management of carbon & energy, noise & vibration, dust & air quality, pollution control, water & material resources, archaeology & historic environment
  • All contracts use BREEAM (stations) or CEEQUAL (tunnel, portals and shafts) as an environmental assessment methodology and benchmarking tool
  • All personnel employed on the project are to be paid the London Living Wage.
  • Contractors must use of CompeteFor and Diversity Works for London to allow local business to compete for work and achieve good diversity practice
  • All contractors are required to produce Community Investment Plans.  This requirement is aimed at encouraging contractors to deliver time and money to good causes locally – putting something back into the communities where Crossrail’s construction works are causing the most disruption
  • All Contractors must register with the Considerate Constructors Scheme.  The Crossrail average is 42.5 (national average of 34.64).
  • Crossrail has set a target of 400 new apprenticeships working on Crossrail for at least 16 weeks.
  • Crossrail has established a free job brokerage service.  Jobcentre Plus is working with our Contractors and with a network of local outreach agencies to identify and advertise job vacancies and help equip local people to compete for these opportunities.
  • Project bank accounts (PBA) – All tier 1 contractors are required to establish PBAs to pay sub-contractors.  Crossrail can monitor the balances to ensure they are maintained at a low level indicating that suppliers are being paid promptly (within 30 days). This is vital to ensure that money is flowing to vulnerable SMEs/li>
  • Risk mitigation – supply chain exposure is continually monitored to ensure that risk is spread and that suppliers i) have capacity to supply to Crossrail and ii) are not overly dependent on Crossrail as a sole or predominant customer

1 Encouraging a diverse base of suppliers , promoting fair employment practices, promoting workforce welfare, addressing strategic labour needs and enabling training,  community benefits,  ethical sourcing practices; and promoting greater environmental sustainability.

Crossrail working groups, for a and other enablers for industry best practice

Crossrail recognises that contractual requirements alone are not going to deliver world-class performance.  The importance of having a common vision, collaborative working environment and performance incentives is also vital in ensuring successful outcomes.  Collaborative working and information sharing in order to accelerate performance improvement has been promoted through a number of fora.  For example Crossrail runs:

  • A regular Contractor Environmental Managers forum and collaboration website to share best practice and lessons learned across the programme of works.
  • A regular Ethical Supply Chains in Construction working group with procurement specialists from our tier 1 contractors who are working collaboratively to mitigate risks in the supply chain.  The work of this group has received external plaudits for the work that it is undertaking.
  • A project carbon working group bringing together corporate sustainability managers from across our tier 1 contractors, to work collaboratively and mobilise their combined procurement power to deliver a lower carbon solution for Crossrail, and develop industry knowledge for future projects.  A focus of this group is to demonstrate tangible links between lower carbon and lower cost.
  • An innovation programme, unique to a temporary organisation. This programme legitimises our workforce to promote ideas that can improve the efficiency of construction.  The Innovation Forum evaluates ideas in the form of a competition and provides funding for implementation. Ideas can be of a scale for implementation on Crossrail or of a more experimental nature to provide confidence for future projects.

An analysis of the 400+ submissions to the innovate portal have shown that many are sustainability related. As such, the huge power of implementing a project innovation programme to harness sustainable project benefits is immense. We are also starting to see emerging correlations between the level of innovation within our contractors (and their supply chains) and their overall performance in the supplier performance framework. Furthermore, there is emerging and powerful data linking organisations that innovate with greater profitability.

The organisational structure of the platform ensures that contributing contractors each benefit from the programme with very little investment, and the project can act as an accelerator to bring solutions to market.

Measuring performance on Crossrail: tools and targets

Construction Energy

Discussion within the industry and notably Constructing Excellence2 (CE) highlights that there is little benchmark data for the heavy construction activities being undertaken on Crossrail.  We are thus pioneering an approach to understand the entire carbon footprint of Crossrail over its operational life, but also focusing at the present time on construction energy. This has led to carbon reductions of up to 20 per cent, with an average of over 8 per cent across the programme. Crossrail data will be made available to the industry through CE. We have also developed a number of spreadsheet based macro calculations that can be “plugged in” to our construction carbon footprint module so that the benefits of a particular technology or initiative in reducing energy and carbon can be immediately calculated and the impact on the out-turn carbon seen.


Crossrail uses two environmental sustainability evaluation schemes, BREEAM & CEEQUAL, a description of which follows.

BREEAM (Building Research Establishment Environmental Assessment Methodology) is an environmental assessment method and rating system for buildings, with 250,000 buildings with certified BREEAM assessment ratings and over a million registered for assessment since it was first launched in 1990.  It is similar to LEED, ESTIDAMA, and GSAS.  Crossrail is the first project to utilise BREEAM for the assessment of an underground station.  Through collaboration with the Building Research Establishment, Crossrail has developed criteria that are suitable for this type of building.  This is an industry leading initiative allowing future benchmarking for underground stations.

CEEQUAL (Civil Engineering Environmental Quality) Award Scheme was launched in 2003 and is a similar scheme for civil projects and is being used to evaluate Crossrail’s tunnel, portal & shaft structures.  A recent equivalent in the USA is ENVISION which was developed after consultation with CEEQUAL Ltd.

The use of these methodologies has provided a rigour to the evolving design process and has aided the focus on poorly performing areas such that improvements can be made.  Contractor performance can also be measured through the use of CEEQUAL which has a heavy points weighting on the physical construction process and environmental management thereof.

The transitioning of both the BREEAM & CEEQUAL processes to our contractors has allowed them to seek areas for improvement and performance is rewarded through the Supplier Performance Framework.

2 Constructing Excellence is the single organisation, in the UK,  charged with driving the change agenda in construction. It exists to improve industry performance in order to produce a better built environment. It is a cross-sector, cross-supply chain, member led organisation operating for the good of industry and its stakeholders.

Excavated Material & Construction Waste

Crossrail has set targets of 95 per cent and 90 per cent respectively for the diversion of these materials from landfill to beneficial use.  The project is currently in excess of both of these targets, with nearly 100 per cent construction waste being diverted from landfill and 99 per cent of excavated material being beneficially used, a significant volume of which is being used for the Wallasea Island wild coast project.

Diesel Emissions Control

Crossrail is committed to reduce emissions from non-road mobile machinery where reasonably practicable. The use of these cleaner engines will contribute towards improving air quality in London and particularly for Crossrail’s local communities.

Since 2010, we have been working with contractors to implement this requirement and to overcome concerns relating to equipment reliability, maintainability and adverse fuel consumption.  By 2013/14, 73 per cent of all plant used on the project had been fitted out with diesel particle filters (dpf) or have been procured with Stage 3b engines. Trials have proven that it is not practical to fit emissions control to 19 per cent of plant at this time (equating to 92 per cent compliance).  This programme has been instrumental in increasing the capacity and therefore availability of dpf fitted plant & equipment to the London & south east of England market.

The impact of Crossrail on stimulating growth, jobs, skills and community benefits

As the largest infrastructure project in Europe, Crossrail is creating jobs and stimulating growth in the UK. Data representing 1751 contracts from tier 1 to 3 indicates that 62 per cent of the project’s supply chain spend is taking place outside of London and 58 per cent are SMEs. 97 per cent of Crossrail related contracts are being delivered by UK based companies.

This data has been used to map the geographic distribution of the supply chain (Fig 4), highlighting some of the specific opportunities being delivered around the UK.  The project has so far supported the equivalent of 13,800 full time jobs right across the UK, with three out of five of these jobs outside of London.

Another key objective for Crossrail has been to ensure engagement with the supply chain, and importantly to try and create new opportunities for companies that may not otherwise have the opportunity to work on a programme such as Crossrail. Our use of CompeteFor, an online resource that flags up potential contracts to these companies, has proved a successful tool in promoting opportunities and bringing new suppliers to the table. Given the opportunity to perform, there is every chance that these companies can become more regular members of the supply chain to our tier 1 contractors.  We will be doing more analysis on just how successful this has been next year.

London is an expensive city in which to live and work, and it is important that the more vulnerable members of our workforce are protected through payment of the London Living Wage3.  A programme of audits is employed to ensure that this is being complied with, and we are not aware of any non-compliance in this area.

3 The London Living Wage is the hourly rate of pay that the Greater London Authority Economics calculate each year, taking into account the higher cost of living in the capital and the rate of inflation, which is needed to be paid to someone to allow them an acceptable standard of living above the poverty threshold. It is defined by GLA Economics as “a wage that achieves an adequate level of warmth and shelter, a healthy palatable diet, social integration and avoidance of chronic stress for earners and their dependents.”

Community Investment Programme

We work in close proximity to our communities.  A project such as Crossrail is built in the heart of the city and the impacts on local community can be significant.  Furthermore, the duration of the works means that our contractors are very much part of the community for the duration of their tenure on the project. We therefore require them to put something back into the community and this takes the form of various initiatives.  In some cases, this may be simply providing money for a community project, but more typically takes the form of donations of construction materials for community projects, or volunteer time to assist on projects.  Crossrail Ltd also has its own Community Investment contributing to the programme focusing on a number of schools in the area and linked in with the Young Crossrail initiative. Young Crossrail is our education programme for students.  It targets both junior and senior school students with appropriate educational materials.  It has been set up in response to the increasing challenge in the UK of attracting people to the engineering & construction industry. A career in engineering can be exciting, varied and rewarding. Whilst our mission at Crossrail is to deliver a world-class railway for the 21st century, engineering also plays a key role in a broad range of industries outside the transport sector and this programme is designed to take this message out to local schools. We have a number of volunteers from the project that go out and work with the school, but resources are also available for the schools to work on their own.

Rewarding our contractors

In 2013, a decision was made to reward our contactors for their sustainability endeavours.  To this end, the Crossrail Annual Sustainability Awards were launched with entries invited in the three categories of economic, environmental and social sustainability. This is also very much linked to our learning legacy and the sharing of information across the industry.

We also recognised the importance of instigating behavioural change and initiated a campaign known as Green Line. Contractors are required to demonstrate above compliance performance across a number of environmental criteria to be awarded the green line. The line is a physical and visible symbol at the site entrance to signify a best practice site and promotes pride amongst the workforce. During the year, Green Line recognition was awarded to seven contractors and partner organisations. The above compliance requirements of recognition under the Green Line also feed in to the supplier performance framework, thereby providing additional reward.

Crossrail supply chain
Fig 4. Geographic distribution of the Crossrail supply chain


In summary, it can be seen from the approach taken on Crossrail that an early and clear definition of sustainability with clear lines of ownership, responsibility and governance can be co-ordinated and managed across diverse interests to provide benefits that are balanced and address social environmental and economic needs.  The outcomes from this are demonstrated through the results and confirm the success of this approach which we commend to other major projects.

On completion Crossrail will leave a tangible physical legacy but arguably the intangible legacy of a change in construction industry sustainability performance, and the recognition that the benchmark for construction and major projects has been raised will be a greater achievement.  Crossrail is paving the way for future projects and is proving that it can be affordable and, indeed, financially and economically beneficial to pursue sustainable outcomes, particularly when wider benefits to the national economy are taken into consideration: the contribution to the economy realised through improved accessibility and journey time being the more direct benefits, but wider benefits such as the opportunity for employment, training and supply chain enhancement are derived through investment in sustainable infrastructure.  The authors would argue that this is a vital consideration in the calculation of benefits when undertaking evaluation of infrastructure projects, although we would accept that the industry would benefit from further tools to aid this evaluation.