'Cambridgeshire Autonomous Metro system not the answer' experts warn
Cambridge needs to transform its under- pressure transport network, but experts say a metro system is not the answer.
Gareth Dennis, director of consultancy Permanent Rail Engineering, believes the selection of the Cambridgeshire Autonomous Metro (CAM) as the preferred option for Greater Cambridge is “pretty shaky”.
“Even if Cambridgeshire can justify its own mass transit system, excluding cars from the city streets and enabling a free-flowing light rail system would be much quicker to build and more cost-effective,” he told the Cambridge Independent.
Campaign group Smarter Cambridge Transport says “the economic case for any sort of network on the scale proposed is highly debatable”.
The Cambridgeshire and Peterborough Combined Authority published its strategic outline business case for the £4bn electric-powered CAM last month.
It also agreed to approve £1m of funding to undertake the next step of creating an outline business case and the scheme has the support of the mayor, James Palmer.
The CAM would serve the inner transport corridors in Greater Cambridge area, from the city to Cambourne, Granta Park, Waterbeach, and Newmarket Road and Trumpington Park and Rides – a total of 142km.
The scheme would include 12km of twin-bore tunnels under Cambridge to provide two underground stations, one in the city centre and one at the main railway station.
Mr Dennis, a lecturer at the National College for High Speed Rail, has spent the past few years looking at new transport systems, such as hyperloop and driverless transport, and examining whether or not they are “a good idea or a form of pseudoscience”.
“When I look at a transport system, the first thing I look at is its capacity,” he explained. The CAM scheme proposes 36 services per hour through the ‘core’ city centre section. “That defines how resilient your system needs to be,” he said, adding that high numbers can justify spending a lot of money on the infrastructure.
“The service provision through the central section is 36 buses per hour, which is an incredibly intensive service. That’s comparable to the London Underground,” he said, where similar numbers are seen in peak times on the Central and Victoria lines.
“To suggest a bus can run that level of frequency, immediately you raise an eyebrow because all of a sudden you’ve got to have a very resilient timetable, lots of drivers, and that infrastructure has got to be really good.
“Where high-intensity bus services run the roads start crumbling up. Potholes are an issue across the UK and those are exacerbated by the big heavy wheels of a full bus.”
Mr Dennis says the evidence suggests that a tram would be better suited to Cambridge, as the initial cost would be saved with less long-term infrastructure work. It would also be easier and cheaper to extend.
“The cost per passenger is more for a bus than for a tram even though the tram unit itself is a bit more expensive,” he said.
“LRT vehicles are much lighter than their bus-tram equivalents. Externally-powered LRT vehicles are also less complex and therefore cheaper to maintain than an internally-powered (by battery or otherwise) bus-tram,” he added, suggesting a trolley bus that gets power from overhead cables would be a good compromise.
He raised concerns about CAM’s “eye-watering” tunnelling costs of a “bus in a tube”.
“The unit cost of €92m/km is far greater than that of Crossrail, which is mad if you consider the specification of the two systems,” he said. “You only need to look at the various historic city centres in Europe and they all use trams. The capital cost is larger but actually it lasts much longer, but for the bus metro you’ll be resurfacing it quite regularly.
“The total cost of the Edinburgh tram scheme, which famously overrun, was just under £800m. The phase one and two of the Nottingham tram systems cost about £900m and the airport extension of the Manchester Metro link, which is almost 50km of tramway, cost £400m. You can see the magnitude difference and the time to deliver these is much reduced.”
Chris Rand, a spokesman for SCT said they were in almost complete agreement with the assessment made by Mr Dennis, but go further and say that the case for any sort of network on the scale proposed is debatable.
“Gareth has backed up several of the points made in our own criticism,” he said.
He continued: “Sadly, the Combined Authority has already rushed to give its transport director the go-ahead to commission an outline business case, despite all the concerns raised about the Strategic OBC.
"Gareth compares the metro proposal with light rail, and rightly concludes that light rail would be better. However, we think that the economic case for any sort of network on the scale proposed is highly debatable.
“Smarter Cambridge Transport would prefer to see money spent more quickly, on a wider variety of interventions that would benefit more residents and businesses over a wider geographic area."
Along with the CAM, which is expected to be built between 2023 and 2029, transport body the Greater Cambridge Partnership is looking at a package of measures to tackle congestion on the city’s streets.
These include a workplace levy, congestion charge and or closing streets off to traffic.
Mr Dennis said the ultimate problem was traffic in the city centre, which would not change with CAM.
He said: “The issue is the unwillingness to relinquish the streets to pedestrians and trams and get rid of motorised traffic.
“If you want motorised traffic and trams, you’re not going to fit it on the roads. But, actually the reduction in pollution from not having motorised traffic would be huge.
“It feels like a no-brainer to me. Building clean transport is the perfect excuse to improve air quality in the centre of the city and to enable more pedestrians and cyclists.
“I realise that there a challenge politically to exclude cars but the fact that people are dying due to complications with air quality. It’s a public health issue and at some point Cambridge is going to have to have a low emission zone at which point you’d exclude the cars and you’d be half way there.
“The cost would be a quarter of the cost. The cost to build a tram system.”
He cited both tram systems in Manchester and Birmingham that have recently been extended quickly and cheaply, something that he says won’t be possible with CAM.
“Impossible,” he said. “The platforms will have to be straight to make sure you get a nice smooth access on and off the trains for people with reduced mobility. You set the angle of those platforms and the track that connects them will be curved, so you can’t them put a station on that curve without redigging all the tunnels. It’s locked in.”
A Combined Authority spokesperson said: “The extensive development of the CAM concept through the strategic outline business case (SOBC) found that it was the only viable option for a metro network that extends beyond the city fringe. CAM provides the capacity, quality, accessibility and reliability to transform the quality of public transport across Greater Cambridge, and will support future growth.
“There is not the scale or density of demand to support an equivalent tram system in Greater Cambridge without significant ongoing subsidy, and a tram would therefore not be an affordable or deliverable solution.
“The CAM scheme concept has been substantially developed through the SOBC, including the extent of the overall system and its tunnelled elements.
“The direct cost comparison between the SOBC report and Mass Transit Options Study is therefore not valid.”