Cambridge Futures was established in 1996 and contributed to forward-thinking strategic plans for the future of Cambridge and its surrounding region in two distinct phases, the first of which won the Royal Town Planning Institute Award for Innovation 2000. The initiative was led by international expert in planning and urban design Professor Marcial Echenique at the University of Cambridge Department of Architecture, with strong leadership contributed by Jonathan Barker of Marshalls, and had broad participation within the Cambridge community. The first phase, Cambridge Futures 1, explored seven scenarios for Cambridge against economic, social and environmental criteria. Computer models were used to analyse scenarios, with strengths and weaknesses highlighted.
Cambridge Futures 2 focused more specifically on transport as the critical issue facing the Cambridge region, and adopting a similar scenario-based methodology published its findings in 2003 (Echenique & Hargeaves 2003. Cambridge Futures 2. Department of Architecture, University of Cambridge). Public transport options based on bus transit with a “high degree of segregation” were modelled in Cambridge Futures 2, and included a network of underground tunnels in the city centre. The modelled options included a 3.3 km east-west bus tunnel extending from the Newmarket Road area to the Adams Road / Grange Road area, and a 2.7 km north-south tunnel extending from the Cambridge rail station to the central underground bus station located around Drummer Street, where the two routes would connect. “Cut and cover” tunnels were suggested, where trenches are excavated along streets and covered by structural slabs.
The tunnels would facilitate rapid transit between these four entry points on the compass to the inner city bus station. In the north of the City, a dedicated busway would run the length of Milton Road to connect with the Cambridge-Huntingdon Guided Busway near the Science Park. Bus rapid transit would also extend from the Science Park around the A14 area to the NIAB / Darwin Green sites, Huntingdon Road, the NW Cambridge site and the West Campus (at the time neither the West Campus nor NW Cambridge were developed). In the west the busway would enter a tunnel near Adams Road to access the inner city, and a bus link from Cambourne was also suggested to run along Madingley Road. In the south a tunnel would connect at Cambridge rail station with the southern Guided Busway to Addenbrookes / Trumpington, and extend north to the Drummer Street bus station and Grafton Centre area where it would connect with the suggested east-west tunnel. The “east-west tunnel would facilitate a high speed route through the city between the Madingley Road and Newmarket Road park and ride sites. The north-south tunnel would provide a high speed route through the city centre for the proposed Huntingdon to Trumpington HQPT [High Quality Public Transport] scheme, also connecting the Cowley Road and Trumpington park and ride sites” (Echenique & Hargeaves 2003: 28). Underground stations were envisaged at Market Square, Parker’s Piece, the Grafton Centre and Coldhams Lane. In the east, another surface bus rapid transit route would extend to Cherry Hinton and Fulbourn.
The modelling results projected little demand for an east-west bus rapid transit tunnel, and it was recommended this option be discarded. A more limited “micro-tunnel” using automated vehicles was mooted as an option to explore in the west of the city. At that time neither the West Campus nor the NW Cambridge Site (Eddington) were developed, so presumably forecast demand for travel in the west of the City was low. The model forecast a higher level of use on the north-south tunnel route, at around 1000 passengers per hour in each direction at peak. A modest level of use was modelled along the eastern Cherry Hinton – Fulbourn corridor.
A submission to the City Deal Call for Evidence (Echenique & Barker 2015. Submission to Greater Cambridge City Deal on Cambridge Futures 2) reviewed the findings of Cambridge Futures 2, and noted that improvements to the A14 and M11 are unlikely to be sufficient to cope with the projected demand in coming years. It was concluded that a combination of additional measures will be needed, and in their absence severe traffic congestion will result, with negative consequences for the economy and employment in the local region. They also noted that investment in public transport should be made before introduction of demand management measures such as road pricing, or the lack of effective public transport alternatives would be detrimental for the economy. The authors suggest further research could be undertaken to build on Cambridge Futures 2 and bring it up to date.
A bus-based model may not be directly comparable to Light Rail. Modal shift in transport choices is strongly influenced by the type of transport on offer, and Light Rail has been shown to be more attractive and create greater modal shift than has been possible with bus-based public transport solutions (Urbed 2015. Trams for Oxford: could light rail improve our historic cities? Urbed, London). Light Rail is also capable of greater passenger throughput than buses, and this may also influence results. These aspects of the Cambridge Futures 2 simulations, substantial changes and growth that has occurred since the work was undertaken, and other differences such as the number of stops, makes it difficult to translate the results directly to a Cambridge Light Rail network. However, the project represents one of the most detailed transport simulation studies yet undertaken for Cambridge, and as such offers interesting insights into options that should be considered.
A thoughtful essay by Mark Hogan, dating from mid-2013, reflected on the challenges of transport in Cambridge and the potential of underground, including using Light Rail, as part of the solutions. Hogan “had a brief go at imagining what an underground light rail system for Cambridge would look like” and offered an interesting exploratory model. Hogan proposed three lines, one extending north-south from Addenbrookes to Histon, a second east-west from Addenbrookes to Fulbourn, and a third east-west extending from NW Cambridge site to the Science Park. Hogan highlighted that he had not considered costs, and this may explain the extensive nature of the underground network, which being in the order of 20 km in length would run to many billions. But that wasn’t the point: Hogan sought to provoke thought into alternative approaches to solving Cambridge transport problems, and as such it is a useful contribution to the debate!
Geotechnical and Environmental Research Group, University of Cambridge
Professor Lord Mair (CBE FREng FRS), Sir Kirby Laing Professor of Civil Engineering and Head of Civil and Environmental Engineering at the University of Cambridge, is a worldwide authority on tunneling, and has played leading roles in projects such as the Jubilee Line, Channel Tunnel, Crossrail and many others worldwide. Specifically, the Cambridge News reported on his 2008 research into the technical feasibility of tunneling in Cambridge for underground transportation, and that Prof Lord Mair concluded that the Cambridge gault clay was “ideal” for rapid and cost-effective tunneling. Prof Lord Mair went further to say that he believed there is:
“a need for radical solutions to Cambridge’s traffic problems. We have a very historic city centre with narrow streets which hinder public transport provision and there is no question that buses and cars are causing increasing congestion and pollution.”
Prof Lord Mair dismissed suggestions Cambridge was too small for a project of this scale, and noted examples exist in Europe where relatively small lengths of tunnel have led to major environmental benefits. According to Prof Lord Mair, a key consideration is not only the size of the city, but the nature and importance of its environmental and historical heritage. He expressed concern about the impact traffic congestion was having on the city, and believed residents would welcome reductions in the number of buses that ply the narrow streets. The underground approach was considered “hugely advantageous to the city of Cambridge” and he encouraged the city and regional councils to dig deeper.
The 2008 underground scheme developed by Prof Lord Mair and colleagues at his Geotechnical and Environmental Research Group in the University of Cambridge was an indicative conceptual model showing ‘aspirational’ routes for ‘High Quality Public Transport’ links. These links, similar to the Cambridge Futures 2 study reviewed above, were explored for bus transit, although it was noted that they could be suited to Light Rail or even new road tunnels. The system extended as far as Cambourne, Northstowe, Cambridge Research Park in Waterbeach, and Granta Park in the south, although clearly the underground component was focused on the historic City core. Closer within the Cambridge City limits, the suggested links extended between the West Campus, the Science Park, the City Centre, Cambridge Rail Station, Fulbourn, Marshalls and the Biomedical campus at Addenbrookes. The intention was to investigate in more detail as part of the City Deal and hopefully this will be supported.
The model proposed by Prof Lord Mair’s group bears similarity to that proposed by Cambridge Connect, although the two were developed wholly independently: we were not aware of the earlier work until after our proposals were developed. We are struck by the conceptual alignment between proposals, which perhaps lends confidence to the scheme layouts because they were derived independently. At this stage of the research by Cambridge Connect, Light Rail remains preferred over bus-based solutions because it is supported more strongly on the evidence of environmental, capacity, scalability, speed of passenger exchange, energy efficiency, likely modal shift and consumer preference grounds. Light Rail is, of course, more expensive. However, we recognise that any eventual solution needs to be multi-modal and well-integrated, with local buses forming an essential service to areas within the City core that would be less accessible to a Light Rail network, and with express buses more suited to connect the outlying towns and villages beyond immediate practical reach of Light Rail on the grounds of cost.
Prof Lord Mair reaffirmed the suitability of Cambridge geology for tunnelling in a recent news article in CapX (04 Mar 2016), which reported that early results of a feasibility study currently being carried out to establish whether it’s viable to build a series of mass transit tunnels under the city found that the alluvial soil overlying chalk and flints beneath Cambridge is good for tunnelling, and even better than London’s clay.
Railfuture East Anglia has actively promoted rail as an important component of public transport for many years, with the principal focus in the Cambridge region being improvements to the heavy rail network. In 2015 Railfuture East Anglia developed concepts related to Light Rail for the Cambridge City area more specifically, and made a submission to the Greater Cambridge City Deal Call for Evidence on Light Rail. The submission noted the historic values of Cambridge, and expressed concern about growth in public transport by bus into the city centre.
The potential of Light Rail, including with an underground component, was highlighted, and the submission suggested a twin-track tunnel of around 4 km extending from Cambridge Rail Station under the city centre and towards the West Campus site. An overground component was proposed to extend from West Campus through the NW Cambridge Site to Darwin Green near the A14, which was envisaged to link with guided bus and / or new priority buslane services extending along highways on the north and west of the city (i.e. A14 / M11).
A scheme proposal was not elaborated in detail, although the main intention of the submission was to highlight the potential of Light Rail as an option for public transport in the future, and to raise awareness of the need to start to safeguard / set aside potential routes that could be anticipated. It was argued that Light Rail should be considered as part of the overall transport strategy within the region.
Illustrative scheme for a Cambridge underground – Alex Reid
Alex Reid developed an outline scheme for a two-line underground network using ‘Automated People Movers’ (APMs), which was submitted to the City Deal ‘Call for Evidence’ in Nov 2015. One line would extend from the current Madingley Park & Ride site in the northwest to Addenbrookes and the Babraham Park & Ride in the southeast, routed via the West Campus, city centre and Cambridge Central rail station. A second line would extend from the current Trumpington Park & Ride site in the southwest to the Science Park and Milton Road Park & Ride site in the northeast, including stops at Cambridge Airport, the Newmarket Park & Ride and Cambridge North rail station. The two lines would meet at Cambridge Central rail station. The routes proposed share much in common with the proposals developed by Cambridge Connect.
APMs are relatively small and light vehicles similar to those used at Stanstead airport to move passengers between terminals. They were favoured because of their ability to operate in driverless mode, and because these vehicles allow smaller platforms than conventional underground trains, both of which help to reduce the overall cost of the scheme. It was suggested that passengers could wait for underground APMs at the surface, being called down in appropriate numbers as APMs approach stops, which would help to minimise investments needed in underground stations. This is an interesting concept that warrants further exploration, and evaluation of technical aspects such as speed, passenger throughput capacity, reliability, and consumer perceptions as well as the economics should be undertaken.