VLR, the comeback of little Railbuses

How can we respond to traffic on short lines where the criteria of conventional railways are too cumbersome and uneconomic? By returning to an old idea: the very-light railcar, close to the automobile world.

There is renewed interest in very light rail vehicles. The emerging very light rail sector (VLR) aims to remedy to the problem of the design criteria of conventional railways, which are very different from those of trams or subways, for example, by utilizing the technology from the automotive sector. It want to create hybrid or fully electric self-propelled vehicles that are light (less than 1 ton per linear meter), energy efficient, cheap to manufacture with low operating costs and adapted to the needs of society. This immediately brings to mind what was tried in many ways in the 1930s.

With offices in the UK and Australia, Transport Design International Ltd (TDI), founded in 1987, is a industrial design and engineering consultancy. This design firm specializes of advanced, sustainable, urban transit solutions such as the Minitram System, Revolution VLR (very light rail) and Vectus PRT (personal rapid transit).

The ultra light trains can contribute to the reopening of old or abandoned sections of the railroad and to new low-cost projects for light tram trains in smaller British cities or regions with strained economy. The aim is to increase the number of passengers within rail public transport, thereby reducing emissions and creating more favorable conditions for cities around the world. According to these designers, this type of vehicle would make it possible to meet climate challenges without having to spend money on heavy railroads.

Why tram-train is not the solution
Coventry is among the 28 UK cities tracked by the government in 2017 with NO2 levels that will exceed the legal limits in 2021. The city recently devised a strategy to combat these high emissions with short-term measures to improve street, bike and pedestrian connections. It intends to improve its public transport network in the longer term. Light rail or tramway, such as the neighboring cities of Birmingham and Nottingham, has introduced is an effective way to do this. Both cities’ grid networks report ever-increasing traffic flows and also economic expansion in the areas that have introduced light rail traffic.

However, for cities like Coventry, it can be difficult to finance extensive traditional and usually expensive rail projects. The city has a population of 350,000 and also a record number of low income earners. Birmingham’s Midland Metron’s latest 11-kilometer extension from Wednesday and Brierley Hill cost £ 449.5 million, or £ 40.9 million per kilometer, an increase of over £ 100 million compared to the original cost estimate when the project started. For Coventry, this kind of tram projects is inefficient and unacceptable in a this considered poor region.

Another example is the cost of a tram-train service between Sheffield and Rotherham, which has risen from £15 million (€16,84 million) to £75 million (€84,19 million), and which showed the complexity of merging the technologies of heavy and light rail, the condition of the existing track and structures and the development of new techniques and ways of working which were more challenging than the project’s planners had expected.

Despite its many advantages, the tram-train concept is an expensive and complex form of public transport. The price is higher if the use of heavy rail infrastructure requires a bi-current traction chain and the additional safety systems, as is the case with the Karlsruhe tram-train, Europe’s most famous example.

In addition, financial excesses experienced during high-profile projects like for example Edinburgh have also deterred some British cities that run or want to run a tramway. Therefore, brand new models and technologies can be the solution for cities with limited financial resources.

Seeking another way
Very Light Rail (VLR) is a research and development project, using the latest automotive expertise developed in the region to deliver an innovative and affordable light rail system. The VLR technology is being developed by Revolution VLR, a consortium led by Transport Design International (TDI) and comprised WMG Innovative Solutions, Unipart Rail, Prose and Trelleborg. In November 2013, the Consortium was successful in winning financial support from Enabling Innovation Team (EIT) of the Rail Safety and Standards Board (RSSB), funded by the DfT), for developing a unique self-powered bogie with an integral, hybrid propulsion system and kinetic energy recovery system.

Following the award of a further grant from the RSSB and new investment from Eversholt Rail and other partners, Phase 2 of the project now continues with the development of a complete, 18m long diesel-battery, hybrid vehicle. The £14.7m three-year project (€16,50 million) brings together academia, industry and the local authority with the aim of developing an affordable, environmentally friendly, autonomous transportation solution.

According TDI, reducing weight and improving energy storage/management offers many advantages over traditional rail systems, including the following:

  • vehicles with low axle weights (around 4 tonnes),
  • self-powered vehicles with energy recovery and storage systems as standard,
  • reduced capital cost and installation time for track infrastructure,
  • reduced infrastructure operational and maintenance costs.

In May 2019 the group announced it had developed a vehicle frame, made from weaved or braided carbon fibre composites into a series of tubes. WMG say the thermoplastic materials used are inherently recyclable, unlike conventional composites. The 18m demonstrator vehicle – which will be able to carry 20 seated and 50 standing passengers – will begin test in Autumn 2020, with testing set to take place, on a site being built in Dudley, UK, which is the Very Light Rail Innovation Centre.

These new centre features a triple-height engineering hall, a reception area, an office space for 45 people, R&D laboratories, meeting rooms, exhibition spaces, an auditorium and a cafe.

Outstanding issues
The idea of small vehicles is not new. But we are still dealing with the problem of the economy of the system. On the one hand, 15 or 20 tonnes of composite materials are still needed to carrier 8 to 10 people at off-peak times, which is not so « sustainable » as announced. Small or not, there is no indication that these vehicles will be full every time they pass. What happens the other way around during rush hour?

On the other hand, the vehicle alone does not do the service. It has to be run on a railway track or a track « assimilated » as a railway. Will the block signalling system be retained? In this case, a small 18-metre vehicle will use 2 kilometres of track for a few minutes. Is this economical compared to a longer train?

Finally, it is not known to what extent the regulatory authorities will accept this type of vehicle, for example at the crash test level. These vehicles will meet the « big trains » in the main stations. Will it be possible to mix them, as the vehicles are not of the same design? Will it be necessary to create one or two specific tracks for light vehicles? Are they going to accept lighter operation of the lines, maybe with the risk of a reduction in speed? All of this needs to be studied carefully.

Sources :

2014 – Railway Technology – Very Light Rail (VLR) Innovation Centre and Rail Line, Dudley

2019 – Railway Technology – Very light rail: new project brings long- held aspiration closer to reality

2020 – Transport Design International Ltd (TDI) website