Can the train take the strain?

Researchers have analysed the environmental impact of the proposed US high-speed rail system. From environmentalresearchweb, part of the Guardian Environment Network
guardian.co.uk, Tuesday 12 January 2010 11.03 GMT
Several regions of the US are planning high-speed electric rail services to cut pressure on congested road and air transport systems. California is one of the areas to have won most public support for the service – a link between San Diego, Los Angeles, San Francisco and Sacramento – as it looks like investment in high-speed rail could provide reduced door-to-door trip times and cheaper journeys than the same amount of investment in transit by auto, air or heavy rail.
Now researchers from the University of California Berkeley, US, have analysed the environmental impact of the proposed high-speed rail system, taking into account not just greenhouse-gas emissions from its operation but also those created during its entire lifecycle, including processes such as manufacturing the train carriages; creating stations; laying track; forming cuttings and bridges; maintaining the system; and generating the electricity required.
"We thought it was important that total energy and emissions accounting be presented for decision and policy makers," Mikhail Chester told environmentalresearchweb. "We think it is important that high-speed rail and the modes it will compete with be evaluated with a comprehensive environmental inventory that includes all vehicle, infrastructure and fuel components that are required to facilitate the vehicles in operation."
The team compared the lifecycle emissions of high-speed electric rail with transport by car, by heavy rail (the Amtrak diesel system) and by air. At the moment around 90% of trips in the California corridor are made by automobile while 9% are made by air and 1% by heavy rail. The equivalent figures for passenger kilometres are 75% by automobile, 24% by air and 1% by heavy rail.
For the high-speed rail system, the team assumed a total of 86 trains based on the German ICE train, consuming 170 kW/h per vehicle and using California's current mix of electricity sources, along with 25 stations and 1100 km of two-way track.
"Energy consumption and greenhouse-gas emissions increase by 15% to 40% [for high-speed rail] from evaluating the 'tailpipe' (vehicle propulsion) component," said Chester. "Carbon monoxide, volatile organic compounds and particulate matter emitted from infrastructure construction are larger than those emitted from vehicle propulsion when normalized per passenger kilometre. Additionally, by looking at low- and high-passenger occupancy scenarios, we show that high-speed rail is not universally better or worse than the other modes."
The trains are likely to have between 650 and 1200 seats; the use of small trains with higher frequency or larger trains operating less frequently could well affect passenger numbers. For the purposes of the study, the team set low occupancy as 120 passengers (10% of the capacity of the longest trains), and the high as 1200 passengers (a full train). When it came to end-use energy consumption, a high-speed rail train with 1011 passengers was equivalent to a car with five passengers.
"It is necessary to consider modes at their best and worst ridership levels to understand the potential of the system," said Chester. "While at the average one mode may be better or worse than another, this may not always be the case and by considering the different utilizations a different set of policies may be drawn to reduce the environmental burdens of a mode, for example, increasing ridership in the off-peak instead of encouraging people to switch to another mode."
The researchers discovered that while high-speed rail may lower energy consumption and greenhouse-gas emissions per trip, the current electricity mix in California means that it can create more sulphur dioxide emissions, leading to environmental acidification and human health issues.
In a study last year, Chester and colleagues found that including lifecycle factors boosted the emissions of train transport by 155% on average. This paper examined commuter rail including heavy rail electric metro, heavy rail diesel commuter transit, and light rail transit (LRT) but not high-speed electric rail for long distances. For cars and buses the equivalent figure was 63% and for air transport, which has relatively little infrastructure for the distances travelled, it was 31%.
Now the team plans to continue evaluating the high-speed rail system once decisions are made for system design, vehicle choice and clean energy options. "We'd like to identify the steps that policy and decision makers should take in developing high-speed rail systems to minimize their environmental burdens by considering appropriate transit integration to increase ridership, vehicle design selection to operate appropriate-sized trains, and the potential of integrating cleaner sources of energy," said Chester.
The researchers reported their work in ERL.