25 February 2020 · Vivarail
Presenter: Adrian Shooter – CEO Vivarail
Long-time career railwayman Adrian Shooter described how he had retired about 8 years ago but quickly became bored after only two weeks of retirement. Feeling that the rail industry was very conservative and needed something of a shake-up, with his background in mechanical engineering he decided to do something about it.
So why did the rolling stock market need shaking up? With his part in the management buyout at Chiltern Railways came the realisation that with increasing passenger numbers there was a need for more trains, and the knowledge that something better by way of rolling stock was required. It was these experiences that showed him that the cost of designing a completely new train can be prohibitively expensive and he wanted the opportunity to power trains in different ways. A few years ago there was far less concern about environmental matters, but today there are great opportunities to look at more environmentally friendly solutions when powering trains.
Vivarail had settled on buying D78 stock from London Underground as these were being replaced – prematurely, despite them being the best available at the time they were built, and the bogies had been replaced only about 10 years ago. However, Adrian really only wanted the aluminium bodies and eventually bought 228 cars. Along with this he managed to obtain copies of the original notes from the original designer – who is now involved in alterations to the body shells and any technology to be attached to or hung off them.
The idea is to build a variety of trains with zero emissions at the point of use with either three or five car formations and a prototype diesel/battery hybrid is currently running for the Welsh government using the same electrical and mechanical basics as production models will have. With less money for development, the idea is to use modular design and Adrian explained how this works and the testing that is required eg that the brakes give the required performance with both forms of braking in use – dynamic and friction. All of this is built around modern high performance battery technology that will power a unit a sensible distance between recharges. The original test train has 4 generators to keep the batteries charged but the intention is to do away with any need for generators using a modular design so that whatever power unit is in use, it can be easily removed and replaced with an alternative power source eg ‘swapping’ diesel for battery, with the specification that the power unit should be replaceable in ten minutes. All production power modules are designed to fit under the main body to save space.
There was quite a lot of detail about the battery technology, how the initial prototypes were adapted and the results of 3 years of work to improve this to a commercially acceptable standard. One of the aspects highlighted was the lack of information on standards for battery powered trains to work on the mainline, which led to discussions with the ORR on understanding and managing the risks to keep any such risks to a minimal level. After work to manage and mitigate risks and using some pre-existing standards from the marine industry, Vivarail were able to show that they met the required criteria.
Much progress has been made with battery technology with regards to cooling systems to avoid dangerous overheating, and with fast recharge, to make the application in powering trains practical and economically viable. This last means that the units must be as quick to turnaround as conventional units. New external charging units have been developed with pouch batteries and an integral cooling system with a fast recharge time of ten minutes together with technology to prevent ‘any smart 12 year old’ from being able to turn the charge off at static recharging points. It was interesting to note the details provided on the internal design including the use of aviation spirit as coolant in the closed cooling system. This requires careful control and monitoring measuring current, voltage, temperature etc with the facility to cut power automatically if necessary.
A short question and answer session followed the first part of the talk with questions including: physical dimensions of the recharge units; Sheffield trams; cost comparisons with more conventionally powered units; trade-offs in energy usage for heavy batteries when compared with 3rd rail or overhead power supply – it compares well as much work has been done on refining the design. The decision to use aviation spirit as the coolant is to do with heat transfer in the closed circuit which can be used both to cool overheating, and to warm for cold starts, and comes complete with essential integral safety features. Other questions involved the business case for Vivarail’s work and the benefits of what they are doing when it comes to climate change mitigation.
The second part of the presentation provided more information on progress with the new battery units and further planned demonstrations on how well the technology works in practice. There are benefits with re-cycling older bodies (in this case D78 bodies). Adrian also showed comparisons with hydrogen fuel cell technology or combinations of hydrogen fuel cells and batteries, with demonstrations on how these two technologies could be used together. One thing that he made clear is that the hydrogen fuel cells do not power the train but are there to keep the batteries charged when the two are used together. The overall idea is to provide energy efficient trains and trams with comparable or better performance than conventional units, emission free at the point of use and cost effective. He provided some interesting statistics comparing both efficiency and cost between hydrogen powered and battery powered units with an explanation of the figures. Overall the battery technology appears to have a number of advantages over hydrogen fuel cells not least the space required for the fuel cells and the hydrogen fuel, the fuel cost and the additional maintenance required. Vivarail has taken out a number of patents on the technology as a preliminary to franchising it out much more widely, at the same time providing a new standard for the industry. Future developments being investigated are overseas markets; the fast charge system with potential for this to become the UK standard system; and supplying re-tractioning packages amongst other things.
The final question and answer session included the range of battery powered units; the modular technology being developed; pouch cell lithium ion batteries; the ease of replacing modular units with the advantages this can bring when replacements or updates are required; recycling of batteries when they reach the end of their useful life – yes they will be recycled by the manufacturers and the appropriate facilities are already in place; how do the hydrogen fuel cells work; the future; freight as well as passenger transport.
The vote of thanks highlighted the development of a new company with multiple options and the progress made to date. An interesting presentation.