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Cambridge transport: The case for light rail over busways to get city moving



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Opinion | With the Greater Cambridge Partnership executive board due to consider its plans for the Cambourne to Cambridge (C2C) and Cambridge South East Transport (CSET) busways this week, Dr Colin Harris, founder of independent initiative Cambridge Connect, writes for the Cambridge Independent on a different approach to getting the region moving, with RailFuture East Anglia’s Peter Wakefield and Paul Hollinghurst.

The need for change

Cambridge Connect and Railfuture East Anglia have developed a new vision for public transport for the Cambridge region using light rail.

With the challenges of rapid growth and in the context of the climate emergency, we believe public transport needs transformative change in order to offer a genuinely attractive alternative to driving the private car.

Projected Cambridge City & South Cambs population growth 2011-2031 Source: Data from Cambridgeshire Insight, Cambridgeshire County Council 2018 (48321247)
Projected Cambridge City & South Cambs population growth 2011-2031 Source: Data from Cambridgeshire Insight, Cambridgeshire County Council 2018 (48321247)

The population of Cambridge city and South Cambs district has been predicted to grow by almost 30 per cent between 2011 and 2031, adding about 78,000 people and about 45,000 new homes. The busways being promoted by the Greater Cambridge Partnership (GCP) won’t offer the transformation needed.

In fact, public transport by buses in the Cambridge area is stuck at a share of around eight per cent of journeys, with no overall change in share since the first two busways were built 20 years ago. The current busways have failed to drive change at the scale needed.

Why light rail?

Evidence shows light rail is much more effective at driving change to patterns of travel behaviour on the scale needed than is possible using buses alone. It is a proven yet modern technology, operating in hundreds of cities worldwide. Where adopted, it is universally welcomed as a positive and preferable alternative for many journeys that would otherwise be taken by car. This is because light rail offers key benefits that communities need in a public transport system: reliability, frequency, speed, comfort, convenience, accessibility and affordability.

Light rail is fully electric, is very energy efficient, and has almost zero pollution, including of particulates – which are produced by the rubber tyres of buses (and cars) and are harmful to human health. Thousands of waste rubber tyres are produced by bus-intensive public transport as they wear out.

The new Cambridge Connect and Railfuture East Anglia vision proposes two main light rail lines to serve Cambridge and its surrounding region, called the ‘Isaac Newton Line’ and ‘Darwin Line’. Each line is a backbone of public transport, and share the short central tunnelled section in the historic city. Together they are of about 40km in length and would be delivered in two main phases. These lines would replace the busways currently proposed by the GCP, and the southern busway to Trumpington.

Accessibility map of Cambridge Light Rail. Almost 90 per cent of the community lies within a 20-minute walk or an eight-minute cycle ride of a stop on the network, encouraging more walking and cycling.
Accessibility map of Cambridge Light Rail. Almost 90 per cent of the community lies within a 20-minute walk or an eight-minute cycle ride of a stop on the network, encouraging more walking and cycling.

Download a high res version of this map here.

Light rail cannot do the job on its own: it needs to work with the heavy rail network, bus services, private vehicles, cyclists and pedestrians in an integrated way, as it does in all cities where light rail is implemented.

Light rail provides a backbone of mass transit services for residential and employment centres where demand is greatest across the region, with other modes connecting and fanning outward. In time, when needs arise, extensions to the lines proposed can be rolled out. It is typical for transport systems to evolve like this.

Journey times on Cambridge Light Rail: the 20-minute City (48321244)
Journey times on Cambridge Light Rail: the 20-minute City (48321244)

Download a high res version of this map here.

What is light rail?

Light rail shares technologies with modern trams – they use the same rails and vehicles, for example.

The key difference is that light rail uses a segregated way, while trams share road space with other users. It is entirely possible for a light rail line to be both, with the segregated part being ‘light rail’ and the shared part being a ‘tramway’. The main benefits of a segregated way are greater speeds and more predictability.

On the other hand, trams using shared road space can offer the benefit of on-street convenience and accessibility. Around 95 per cent of the network we propose on the Isaac Newton and Darwin lines would be segregated, although street running may be preferable in several areas.

A modern light rail vehicle - an example from Nottingham NET. Picture: Colin Harris 2016
A modern light rail vehicle - an example from Nottingham NET. Picture: Colin Harris 2016

Is Cambridge too small for light rail?

It has often been claimed that Cambridge is too small for light rail. But is that actually true? We know of at least 20 cities in France with light rail/tramways that are of a size similar to Cambridge or smaller, some examples being Orléans, Avignon, Brest and Tours. Many more cities of similar size in Germany, the Netherlands, Sweden, Denmark and Switzerland also have light rail / trams. It is clearly possible for smaller cities to implement light rail, although in the UK this has not yet happened to the same extent.

This is probably in part because light rail generally requires a higher up-front investment, which local authorities appear reluctant to make. Yet, those cities where light rail / trams are implemented typically see the share of journeys by public transport in the region of 20-30 per cent or more, while in Cambridge we continue to languish around eight per cent (excluding heavy rail). Frankly, that is not enough in the context of the climate emergency.

There are several other reasons why Cambridge is not too small: first, it punches above its weight economically, with turnover of Cambridge companies being comparable to Manchester. Many billions are being invested in the Biomedical Campus, West Campus, Eddington, and science parks like Granta Park, among others.

Heavy rail patronage in Cambridge is higher than Nottingham and Derby combined, although we have a smaller population. The pace of growth in Cambridge is the fastest in the UK, and public transit needs to serve the city in the 2030s and beyond, so capacity needs to be adequate.

In addition, the Cambridge population is not simply the inner city, but is around 350,000 when nearby communities in South Cambs are included. This order of population is more than sufficient to support light rail, as is evident from examples in Europe, as well as other cities in the UK. Finally, Cambridge tourism is a large pool of demand not available in many other cities, which changes the demand profile for light rail.

Cambridge has a unique combination of both a vibrant and growing economy and tourism that expands demand for light rail, so the need for public transport capacity is also greater.

The flexibility fallacy

Busway proponents have rightly noted that buses are more flexible because they can travel off the segregated network onto normal roads. While this can be a benefit, extended journey times and unreliability beyond the segregated way can be a powerful disincentive for use. Delays on roads can impact services on the main segregated way, compromising reliability.

Light rail has been shown to perform much better for mass transit, and typically attracts much greater ridership. Where buses are used for metro-frequency services, potholes and cracks in roads need frequent repair. These problems recently motivated the French city of Caen to switch to light rail. Rails deal with these maintenance issues, and offer higher quality ride. Light rail is also around twice as energy efficient because of the very low rolling resistance of steel wheels on rails.

Where there is a need for mass transit, as has been shown in Cambridge, light rail can serve the core while connecting buses serve the wider area. This approach is widely adopted throughout Europe. Fixed light rail infrastructure provides investors with the certainty to make long-term investment decisions to locate businesses or build housing. Flexible connecting bus services beyond the light rail backbone should be planned into the overall strategy to support outlying communities.

Why tunnel?

We have looked at the historical and environmental constraints in Cambridge, and at the practicalities of moving services, as well as the few feasible crossing points on the River Cam, and we believe a tunnel is likely to be the most practical and acceptable solution to enable mass transit in Cambridge city.

In fact, this has already been agreed in policies adopted by local councils and (until now) the Combined Authority, including the Greater Cambridge Partnership.

However, doubts about tunnels have been raised with a change in political landscape after the recent local elections. Without some means to connect together the ‘tails’ of public transport extending out from the city, the public transport network will always be lacking integration, and this will act as a major disincentive for its use. Imagine using the London underground if it did not actually serve the city centre?

Moreover, there is the practical issue of how to accommodate the sheer number of buses required for mass transit on surface roads. We are not persuaded this is desirable for the inner city of Cambridge, and doubt it would be practical. We should be looking for more opportunities to pedestrianise and improve cycling provision, not filling the city with large numbers of buses. Our vision is for a safer and more pleasant urban realm, where people can choose to use public transport that is attractive, efficient and not an imposition.

Attractive and unobtrusive underground entrance in Paris. Picture: Colin Harris 2019 (48321255)
Attractive and unobtrusive underground entrance in Paris. Picture: Colin Harris 2019 (48321255)

It is no coincidence that tunnels have been used extensively for mass transit in other cities. They are relatively expensive, but they offer major advantages. They avoid almost completely all of the major constraints at the surface, which will also incur costs. Underground stations can have a very small surface footprint, some with only an unobtrusive escalator entry at street level. Others are integrated with indoor shopping centres, multiplying the commercial value of underground access. Lifts serve access needs of those unable to use escalators or stairs.

Tunnel costs

So, if a tunnel is needed in Cambridge, can it be afforded? As a rule of thumb, a modern tunnel in Cambridge could be delivered for around £100m per kilometre. Subterranean Cambridge is largely ‘virgin territory’ unencumbered by services and older tunnels, as seen in London. According to Cambridge experts, the underlying clay geology is ideal.

The cost of tunnelling depends upon many factors, including length and complexity. The Cambridgeshire Autonomous Metro (CAM) – which the new mayor Nik Johnson promised to scrap – proposed an ambitious set of double-tunnels around 12km in length, with four portals and two underground junctions. This type of complex tunnel could have a price tag exceeding a billion pounds, and our view is this was unrealistic, unaffordable and undeliverable.

We also think this type of tunnel is not needed. After careful consideration of a range of options, we propose a single tunnel of only a few kilometres could overcome the majority of inner city constraints and still deliver transformative mass transit for the long term. This tunnel would provide the crucial central link needed to enable a fully integrated mass transit system across the city and region.

This short tunnel would run 2.6km from near the Cambridge Central Rail Station to near Grange Road via the city centre. A tunnel of this type would cost about £270m, or at least one-fifth of the anticipated cost of tunnels proposed for CAM. While £270m remains a significant investment, the benefits would be immense. A tunnel of this scale makes good business sense because it would be transformative and serve the zone of highest demand.

The tunnel would protect sensitive inner city heritage, while giving business a shot in the arm by bringing people right into the heart of the city.

Importantly, the tunnel would enable the three major University of Cambridge campuses to be seamlessly joined together with fast travel (West Campus, city departments and colleges and Biomedical Campus). This would ensure university colleges and departments remain well-connected for the long-term, and facilitate business links and scientific collaboration with science parks. The proposed tunnel would also serve the needs of a large proportion of the millions of tourists visiting Cambridge each year, who need access into the central city.

In addition, tourist coaches could connect with the light rail network at a coach park on the periphery, for example at the Girton Interchange, reducing the need for coaches to enter the inner city.

Long-term vision

The Cambridge Connect/Railfuture strategy leverages the strengths of the existing railway network, with light rail being complementary. Our network seeks to use the existing heavy rail network, in which major investment has already been made, to the maximum extent practicable. For example, the railway between Cambridge central station, Cambridge North, Waterbeach and Ely might best serve communities along this axis, and new stations at Fulbourn and Harston should also be considered. A solid light rail network will require more investment than provided through the City Deal, but this is considered justified because:

  • Cambridge is a powerhouse of the economy, and warrants investment to support the challenges of growth;
  • Short-term fixes will not address the scale of the challenges, in particular to drive modal shift away from reliance on private vehicles towards greater public transport use, and to foster substantial changes in behaviour; and
  • The climate emergency demands more ambition for public transport.

‘Greenprint for a sustainable city’

The Cambridge Light Rail concept, showing the Isaac Newton Line and Darwin Line. Diagram not to scale. Prepared by Paul Hollinghurst, Railfuture East Anglia
The Cambridge Light Rail concept, showing the Isaac Newton Line and Darwin Line. Diagram not to scale. Prepared by Paul Hollinghurst, Railfuture East Anglia

The Isaac Newton and Darwin lines are arranged so that almost 90 per cent of the built-up area of Cambridge would lie within a 20-minute walk, or less than an eight-minute cycle ride, of a stop. This could transform the way people move about, with more walking, cycling and use of public transport – reducing pollution and resulting in more healthy outcomes.

Additional lines serving other key areas have been identified, which would be delivered in phases. For example, substantial developments are planned for the east of Cambridge, and these will also need sustainable public transport. We allow for these coming forward in phase three, although the exact timing depends on the time-scales for developments.

Haverhill and Cambourne are also included, where lower cost housing supports employment in the region. There is also potential for onward links to Bar Hill, an important community which is not included in any of the public transport schemes being put forward by the GCP.

We place sustainability at the heart of transport planning, linking closely with the wider regional railway network. This approach offers major benefits to users such as fast journey times, reliability, convenience, comfort, safety and high frequency.

The opportunity to Build Back Better

The busways planned by the GCP were conceived in a different era. For example, the busway in the south east (known as CSET) is projected by the GCP’s own figures to be at capacity on opening, and has limited capacity to expand. This line sits precisely where light rail has the capacity and attractiveness to ensure modal shift, as well as to be future-proofed.

Coupled with a short city tunnel to enable full integration, and rolled out with the Isaac Newton and Darwin lines, we could create a public transport system that not only meets the challenges, but would be genuinely attractive for everyone.

We’ve estimated that phase one of the Isaac Newton line, which includes the tunnel and two underground stations, would cost about £920m. While this would be a substantial investment, it is similar to that made by Nottingham when they built the first part of the NET tram network.

The first two phases of the Isaac Newton and Darwin lines would cost about £1.5bn. This investment would be over a number of years, and could be financed by a combination of mechanisms such as repurposing the existing £500m City Deal fund, creation of a long-term Cambridge Green Infrastructure Bond, a workplace parking levy (as used by Nottingham), Section 106 payments and a Community Infrastructure Levy, as well as Land Value Capture.

How the Greater Cambridge Partnership’s CSET transport route would look
How the Greater Cambridge Partnership’s CSET transport route would look

Soon, decisions will be taken that will irrevocably alter the Cambridge landscape and character.

The vision currently being rolled out by the GCP based on buses will struggle to meet Cambridge needs, and be insufficient to meet the scale of modal shift required by the climate emergency. There are major questions about how a congested historic city core will function with a major influx of buses, and also about the implications for the heritage and environmental values of the city.

In contrast, we have carefully considered the alignments for light rail, using former rail lines and co-aligning with existing highways, to keep environmental impacts at the absolute minimum.

We invite Cambridge residents and businesses to ask: what legacy are we proud to leave to our children?

Find out more about Cambridge Connect via its website.

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