08.12.15
Engineers seek long-term solutions to rail congestion
Rail capacity should be enhanced immediately with investment in new rolling stock, driver advisory systems, and advanced technologies for better control, command and communication, since major infrastructure projects are unlikely to be sufficient to meet demand, the Royal Academy of Engineering has said.
In its first ‘challenge paper’, a discussion document to stimulate debate on the issue of congestion, the Academy said the UK’s rail network suffers among the worst congestion in Europe, with the Department for Transport predicting demand is on the rise.
Conventional supply-side measures are underway: building new lines and stations, adding more tracks and reconfiguring junctions with signalling upgrades, lengthening trains and increasing service frequency. This is coupled with specific major projects like HS2, Crossrail and Thameslink – but it will take “a substantial time for such measures to have a significant impact on overall capacity”, and it is “questionable whether they will be at sufficient scale”.
To mitigate this, the paper listed three key investments that should be made in the short term to improve rail capacity, which will have knock-on improvements for freight and other transport modes.
Rolling stock reform
The first is a programme of rolling stock reform to make trains longer: “New carriages can be added quickly and prior experience shows that small additions to the number of carriages can yield disproportionately positive effects in terms of servicing demand growth.”
However, the Academy acknowledged that the industry’s long-term plan to improve rolling stock allows costs to be spread evenly over the next 30 years. If this were to be fast-tracked over the next 15 years, costs could potentially escalate.
If fast-tracking the rolling stock programme proved impossible, another solution could be to extend the deadline by which domestic industry needs to comply with EU laws on accessibility, the paper said – “pushing what is a voluntary rather than mandatory arrangement beyond its present 2020 deadline”.
“This directive requires the replacement of old rolling stock that does not meet accessibility criteria for people with reduced mobility,” said the paper’s author, Professor Tony May, from the Institute for Transport Studies at the University of Leeds.
“The downside is that delaying replacement would have adverse implications on accessibility goals. However, it would boost capacity by enabling old stock to operate alongside its replacement stock, at least in the short-term.”
Regardless, the paper argued that proceeding with a ‘business as usual’ approach to rolling stock procurement is insufficient, with measures needing to be employed urgently to speed up both procurement and deployment and boost capacity in the short-term.
Driver advisory systems (DAS)
DAS are technologies that use a simple cab interface to transmit information to train drivers on the status of critical junctions or stations they are approaching to help them optimise their speeds to reduce congestion. They are already in use by operators including South West Trains, Arriva’s various operating companies and First Great Western.
These systems provide more information than is currently available through observing lineside signalling, and enable the network controller to advise drivers on optimum speeds, preventing the need to brake or halt severely.
The systems also allows for less energy use through stop-start technology, reduced operational costs and less maintenance of braking systems.
Trains that most benefit from DAS are inter-urban fast services and freight services, which take the most time to traverse a junction.
Until now the systems have been aimed more at improving fuel efficiency than reducing congestion, but Prof May suggested that could change. But he added: “Given the divergent professional judgement within the rail sector and the ease of delivery and subsequent impact of DAS in congestion alleviation, an early pilot scheme should be funded and implemented on a representative congested section of the network.”
The more advanced ‘connected’ versions of DAS, which do not rely on pre-loaded data and timetable information, are more likely to be able to achieve positive results as regards congestion, he suggested.
Control, command and communication (CCC) systems
Lastly, the paper argued that CCC systems – a mix of technologies that facilitate intelligent traffic management and replace lineside infrastructure with communications-based train control – enables trains to be placed closer together on the track. This in turn helps the network to be used more intensively.
CCC systems let the position of vehicles be continuously monitored and updated, enhancing accuracy and removing uncertainties related to trains’ relative positioning. They also allow for more real-time control of trains approaching stations or junctions.
However, the paper said, CCC systems are expensive and complicated to install, with a process incorporating a “high complexity of conversion”. As well as requiring investment in new or retrofitted fleets, CCC would necessitate junction reconfiguration and increased station capacity – both platform and overall passenger space. This would be expensive at locations were capacity is most needed, such as in London stations.
But despite costs, the systems “appear to represent the best intervention in the rail industry for the long term”, the paper said.
May continued: “As network-wide deployment would take 15-30 years, there is a need for intermediate measures to supply much needed critical capacity in the short term.”
The Academy recommended that the government work with the rail operational and supply industry to enhance plans for a first main line introduction of CCC in order to understand the barriers and strategies linked to wide-scale implementation.
It also recommended that the UK learn from countries such as Japan and China where these systems are already widely used.
Prof Andrew McNaughton, technical director at HS2 Ltd, who led the group which produced the challenge paper, said: “Our country and economy are growing. Our transport systems are struggling to cope. Building new capacity is vital but not the universal answer.
“This challenge paper sets out how we can get on top of congestion, but only if we integrate technology advances and policy initiatives, and only if we act now. Working together, government, engineers and regulators can make a difference.”
Prof McNaughton has previously explored some of these issues in a piece written for RTM.