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Cambridge Connect

An abridged version of this article featured in CA72: Cambridge In Context.

Cambridge Light Rail – Greenprint for a Sustainable City

Cambridge is witnessing phenomenal and unprecedented economic expansion and population growth. Over a period of 15 years (2011-31) the population of the greater Cambridge region is projected to increase by ~120 000 people. This is the equivalent of the population of Cambridge city again. As a result, Cambridge is facing some of its greatest challenges. There are pressing needs for more housing and effective transport links, and safeguards for the unique and outstanding heritage, environment and quality of life in Cambridge from these pressures have never been more needed. Given the scale of this challenge, it is vital that solutions developed today encompass long term vision.

Cambridge Connect is a new initiative to promote Light Rail as an enduring and sustainable solution to the serious congestion problems facing Cambridge. Working closely with Railfuture and UK Tram, the initiative promotes solutions that maintain and enhance the outstanding environmental and heritage values of the city and employ practical and well-tested technologies that are fit-for-purpose for Cambridge in the 21st Century.

A multi-modal approach to public transport, involving light rail, heavy rail, private vehicles, buses, bicycles and walking, could provide a radical and long-term solution for Cambridge that is both scalable in terms of capacity and extendible to future destinations as demand and finances allow. 
Greenprint for a Sustainable City – access to the proposed network from within the built-up area of the city and villages within 1500 m of the stops.
Greenprint for a Sustainable City – access to the proposed network from within the built-up area of the city and villages within 1500 m of the stops.

Cambridge Light Rail: The Isaac Newton Line

We propose a light rail route extending over a distance of ~22 km (~14 mi) to meet priority public transport needs within Cambridge City and the immediate area. Extending from the Girton Interchange in the northwest to Granta Park in the southeast; via the University’s West Campus, the city centre, Cambridge Central Rail Station, Addenbrookes, Great Shelford and Sawston and with a short spur extending to Trumpington and a new Park & Ride; the route was selected as a priority following research and an option study involving experts and the public, and is designed to connect with key strategic roads, the national rail system, major employment hubs, and residential areas. 

Dedicated lines

The light rail line would follow existing and former rail routes, run underground within the historic city core, and follow the busway between Cambridge Central Rail Station and Addenbrookes. The line would have its own dedicated track, completely separate from cars and would not run on streets. Some new track alignment would be necessary across the West Campus and North West Cambridge developments to the Girton Interchange, with sufficient space available allowing much of this route to be aligned near to the M11. 
Map of Cambridge Light Rail including Isaac Newton Line and Extensions A, B, C.
Map of Cambridge Light Rail including Isaac Newton Line and Extensions A, B, C.

Future Expansion 

In the future, extensions to the ‘Isaac Newton Line’ could encompass other important employment and residential areas in the city, for example the Science Park and NE Cambridge (Extension A), Cherry Hinton and Fulbourn (Extension B), and linking the Science Park to the Eddington area in what could become a ‘Circle Line’ (Extension C).

At the periphery of the City, the lines would connect to strategically placed Park & Ride sites which in turn connect to outlying towns and villages by express bus services. This would reduce traffic on the main roads into Cambridge, as people switch to buses and Light Rail.

Further extensions to Cambourne and Haverhill (Figure 2), both important residential centres and other destinations such as Waterbeach may also be possible. 

Map of light rail Regional Extensions to Cambourne and Haverhill.

Park & Ride and intercity coaches

We propose a new Intercity Coach Station co-located with a Park & Ride on the M11 near Hauxton. This would allow coach passengers to transfer onto the light rail line, providing a journey time of less than 15 minutes to the city centre and a choice of any stop on the network. This would reduce city congestion and help bus operators keep to a punctual schedule.

New Park & Rides linked to the light rail network would also be established at the Girton Interchange and at Granta Park, while the one on Newmarket Road would benefit from being moved closer to the A14. The Madingley and Trumpington Road sites would be redundant and replaced by light rail stops. 

Greenprint for a Sustainable City

With all city lines completed, the city network would comprise around 43 km of light rail track with around 8 km underground. The 36 stops on this network would be on average ~1 km apart, which is the European standard for city light rail. The result is that over 90% of the built-up area of Cambridge and the villages served by the lines would lie within an 18-minute walk, or less than an eight-minute cycle ride, of a stop (Figure 3).

We propose a fully electric Light Rail network because it is powered with zero emissions at street level, is energy efficient, transports more people per hour while occupying less space than buses, and is fast, reliable, safe, comfortable, and potentially very frequent. On dedicated lines, the vehicles can also operate autonomously, similar to the Docklands Light Railway. All of these attributes make light rail a quality public transport system that people are likely to want to use. They also make it much more sustainable.

This network has potential to transform people’s travel decisions, and encourages people to choose to walk or cycle to their nearest stop for longer journeys on public transport. For this reason we call our plan a ‘Greenprint for a Sustainable City’ recognising fully our need to reduce carbon emissions and our responsibility to build more sustainable cities. 

Journey times and frequency

The journey time from Cambridge Rail Station to the central city would be around 3.5 mins, assuming speeds similar to the London Tube. Journeys from places such as West Campus, Milton Road, Capital Park or Addenbrookes to the central city would be between 9 to 14 minutes. We anticipate trams would operate approximately every 10 minutes, although could be more frequent at peak times, and a frequent service could operate late at night and over weekends, which would be an enormous benefit to employment centres such as Addenbrookes. 

Demand and revenue

Cambridge Connect has estimated Cambridge peak hour commuter demand in 2031 based on population and commuter projections. These data indicate that peak demand from commuters on a light rail line would be around 8000 passengers per hour in 2031 assuming 15% of commuters used the line. This is around 40,000 journeys per day, which is similar to the number of journeys recorded on the light rail lines operating in Besançon and Tours in France.

This estimate does not include non-commuters (people travelling for reasons other than work), which comprises the majority of journeys. Nor does it include tourist demand, and with ~5 m visitors to Cambridge per year we expect tourists to be a very important demand segment. The actual level of total demand would therefore be much greater than indicated by commuters alone. The city of Lausanne, Switzerland, is similar in population and employment profile to Cambridge, and sees more than 40 million passenger journeys per year on its light rail and bus network.

Revenue from the scale of demand expected on Cambridge Light Rail would therefore be substantial. While Cambridge Connect has yet to complete detailed revenue studies, it seems clear that it would be in the tens of millions annually. 

The investment

Preliminary work has been undertaken to estimate the cost of a Cambridge Light Rail network. Comparisons with schemes developed in France and the UK indicate that the Isaac Newton Line would need an investment in the order of £500–800m. By comparison, the Nottingham NET light rail network cost in the order of £850m to develop. The present upgrade to the A14 highway is being undertaken at a cost of around £1.5 billion.

Funds available for the Greater Cambridge City Deal schemes are expected to be £500m, and potentially a further £500m might be unlocked. Light rail and tunnelling schemes have so far been excluded from consideration because they are regarded as undeliverable within the time-scales or funding available through the City Deal.

We recognise that Cambridge Light Rail, if taken up, would require investment and commitment beyond the current scope of the City Deal. However we believe that light rail and tunneling should be given serious consideration for its potential to address long-term needs in Cambridge. Sustainable transport strategies should take into account the need to protect the historic, architectural and landscape values of Cambridge which are of outstanding global importance.

Most importantly, there is a need to connect the three main University campuses (West, Central and Biomedical) to ensure vibrant and cross-disciplinary interactions are maintained between departments and the Colleges, which are vital to Cambridge’s continued strong academic leadership. Effective interconnections are also critical to business. The Cambridge Connect proposals are designed to achieve these objectives, it is difficult to escape the conclusion that a modern, fast, reliable light rail network with an underground within the historic city core would be the best sustainable and practical option.


Map of Cambridge Light Rail including Isaac Newton Line and Extensions A, B, C.

Map of light rail Regional Extensions to Cambourne and Haverhill.

Greenprint for a Sustainable City – access to the proposed network from within the built-up area of the city and villages within 1500 m of the stops.

Nottingham NET Light Rail Vehicle (or tram). Photo: © Colin Harris 2016.