In the days of British Rail, research into railway matters was all tied up. There was British Rail Research and that was it! Actually the organisation didn’t do a bad job, and many engineers around the network had great respect for their colleagues in Derby.
As privatisation approached, this all changed. The Government decided that BR Research was to be amongst the early sales of the BR organisation’s component parts, and in the event it was purchased by AEA and became AEA Technology Rail.
This really ended the era of co-ordinated railway research as we had known it hitherto. The privatised organisation had to act commercially, and so it concentrated on selling the established expertise it inherited from BR Research, developing that expertise in commercially viable ways, and carrying out research on commission when another party was prepared to engage for such to occur.
This left a hole which did not seem to be recognised for some years, all the newly structured rail organisations being very busy sorting themselves out post privatisation. It could be argued that it was really only the crisis over so called “gauge corner cracking” (more properly, rolling contact fatigue damage) after the Hatfield crash that led to a change.
I well remember being involved in discussions after that crash, debating who could be engaged by Railtrack to assist us to properly understand and manage the phenomenon. In the end we engaged TTCI, the research organisation of the American Association of Railroads as a part of the team to do this. It was interesting to note then how the private and disparate US railroad companies had long ago set up a jointly owned rail research body to support their businesses!
Whatever the deciding factor, various people awoke to the need to resume proper, targeted rail research in the UK. One of the organisations to realise this was the Engineering and Physical Sciences Research Council, the EPSRC. A dozen years ago or so, this body decided that it needed to kick start university research into rail matters. As a result, Rail Research UK was formed, and the Universities of Southampton, Birmingham, Nottingham, Sheffield, Leeds, Manchester Metropolitan and Imperial College London (later joined by Newcastle) collaborated through this body to conduct relevant research for about eight years. Each university specialised in a different area of rail interest, Southampton dealing with infrastructure, for example, Nottingham human factors, and Birmingham command and control.
The background just described led in about 2010 to the start of a project named ‘Track 21’. This was a five year research project whose core funding was provided by an EPSRC grant of £3 million. The project was aimed at improving the performance of the existing track infrastructure in the UK. It was recognised that a fundamental reconstruction of the network, such as conversion to a ballastless trackform, was not realistically going to happen. It was therefore well worth taking a look at how ballasted track could be improved to make it longer lasting, more reliable and more economical. The results of the programme were presented to Network Rail staff at The Quadrant in July 2015 by the TRACK21 team.
Briefly, the project considered many factors affecting the existing UK track infrastructure. These included the behaviour of embankments and the effects that trees have on this. The possibility of a better ballast specification was examined, as were the potential use of under sleeper pads, an improved ballast profile and the use of fibre reinforcement in the ballast.
A key factor in improving the economic efficiency of UK ballasted track is the need to maintenance tamp frequently. This is expensive, requires track occupations that would be better avoided, and damages the ballast, shortening its life. If the track geometry could be made more stable it might even be possible to avoid the need for ballast cleaning or renewal at the midpoint in the life of the track. This requirement is currently a major factor in both the cost and the utility of ballasted track. Removing the need would save much cost and greatly reduce the necessity for disruptive engineering works and track possessions.
Track 21 has generated some useful ideas about how this might be achieved. Key outputs included:
- improved understanding and better design techniques for the use of discrete piles to stabilise earthworks;
- clear guidance on the best management of trees on embankment slopes or in proximity to the track;
- improved understanding of embankment slips;
- clear evidence of the effect of increased axle loads on old embankments;
- evidence supporting the benefits of resilient under-sleeper pads;
- evidence of potential benefits from the addition of smaller particles to the ballast grading, and of the possible beneficial use of fibre reinforcement in ballast;
- evidence that use of a biaxial geogrid in the track structure reduces long term settlement and that further research should be conducted into the use of triaxial geogrids;
- demonstration of the benefits of constraining the ballast by means of side restraint or by flatter side slopes;
- understanding of the mechanisms whereby the track geometry deteriorates, for example through variability of substructure;
- demonstration of how track deflection measurements from lineside monitoring and geometry data from measurement trains can be correlated;
- demonstration that ballast fouling by fines actually increases stiffness and reduces long term settlement;
- greater understanding of track-based noise emission and how it may be affected by ballast grading and track renewal.
In all, it came up with some useful guidance and a lot of pointers to potential areas of better understanding and possibilities for improved engineering. Many synergies were created between organisations. The steering group alone, chaired by Network Rail, involved 10 organisations from infrastructure owners to contractors and suppliers. In addition there was an international scientific panel chaired by HS2 and incorporating universities from Sweden, Portugal and Australia together with Systra from France and Deutsche Bahn from Germany. The results were sufficient to encourage the EPSRC to continue to fund the work it had started.
Track to the Future
This is a new project, largely funded by an EPSRC grant of £5 million, but with total funding of over £8 million with industry contributions taken into account. The project is being taken forward by the same universities as Track 21, with the addition of Huddersfield for its expertise on the wheel-rail interface. The team is led by Professor William Powrie of Southampton.
This project has three main themes, Track for Life (design for the degraded state), Noiseless Track and Better Crossing Design. It will focus on measuring things and explaining why things work (or indeed, why they do not and how they can be improved).
A priority is to take on the concept described earlier of reducing tamping and eliminating the mid-life ballast treatment, making the track ballast last as long as the other track components. This will form a key component of the Track for Life theme, together with the search for improved track forms and components and further drives to better understand track stiffness, settlement and standard deviation.
It must be hoped that the industry devotes the necessary resources to supporting this important project. That must include a serious amount of time committed to the project by track engineers who are involved currently in track maintenance and renewals.
Track to the Future is an exciting opportunity for the rail industry, and in particular it offers the UK a chance to really examine why our track system costs appear to be higher than those of similar rail networks in mainland Europe.