Electrification has received some negative press coverage over recent times, with delays to major projects and significant cost overruns being widely reported. Why should this be and what has gone wrong?
Part of the problem is that there has been a significant gap between the last major project – East Coast in the late 1980s – and authorisation of the more recent schemes such as the electrification of the Midland main line, North West, and Great Western main line, the latter only recently scaled back yet again following demands from the National Audit Office. In that time, many of the people with electrification skills had either retired or moved elsewhere, and a dearth of knowledge has been a major factor in getting these projects progressed.
However even if that were not the case, the planning and design methodology, as developed in the 1960s through to the 1980s, is out of date. It relied on manual surveys, paper records and slow agreement between affected disciplines to get the necessary sign off, along with a restructuring of the railway and more complex contractual relationships post- privatisation. These processes have been part of the problem and are not commensurate with the digital railway initiative.
So what can be done to improve this state of affairs? Rail Engineer met with the Atkins electrification team to learn of the work that has been carried out to develop new design and planning tools. In the context of this article, electrification relates to overhead line 25/50kV systems, although it is perfectly possible that some of the design features could benefit any further expansion of the 750V DC third-rail network.
The basic requirements
To outsiders, planning a line to be electrified is a relatively simple process. You work to a set of standards to decide the type of electrification required. Survey the route and mark where structures and gantries need to be, order the materials, arrange a contractor, obtain the necessary possessions, carry out the installation, do some power up tests, run some test trains and hand over as commissioned. Unfortunately the real world is not like that and many other factors have to be taken into account before any real work can begin.
Firstly, it must be understood that electrification involves many engineering disciplines, the main one of course being OLE itself, which includes skills associated with mechanical, electrical, civil, structural and geotechnical engineering. Others include general civils for embankments, retaining walls and bridges, permanent way for line speed and track alignments, signalling for signal sighting and interference, telecommunications for immunisation requirements, traction and rolling stock for types of train and associated characteristics, operations for train planning and service frequency.
All in all, it is a very complex matrix, and one where innumerable consultations have to take place to satisfy the concerns and requirements of everyone.
The traditional sequence of events to create a plan for an electrification project is:
» Produce a layout plan following route surveys; » Validate the layout plan with all concerned;
» Undertake an interdisciplinary design check and an interdisciplinary review;
» Carry out a structural analysis and produce foundation designs
» Do a detailed cross-section design for every individual structure and produce a materials allocation;
» Carry out dropper calculations for the catenary wire;
» Produce a construction submission.
All these steps require separate documentation that then has to go through interactive consultation, which is a time consuming exercise. What if all this could be captured and logged on to a single information source that could then be shared by all interested parties and thus form an ongoing electrification plan to be used as a database for the totality of the project?
Electrification engineers within Atkins have been working on such a solution since 2011. They have built on learnings from the Innovate UK-funded Digitally Enabling Electrification project, which saw Atkins work with partners Laing O’Rourke, DHP11 and Imperial College to research and develop digital solutions to enhance productivity throughout the electrification lifecycle.
The resulting design solution represents the next stage in this thinking and has been deployed to deliver ever-increasing functionality to both railway infrastructure providers and electrification contractors over the last five years. A brief preview of this was given in the June 2016 issue of Rail Engineer and is now described in greater detail.
TADPOLE
Every good innovation deserves a catchy acronym, this being Tools Aiding the Design and Production of Overhead Line Equipment – TADPOLE. Designed by engineers for engineers, the concept to combine all the individual elements of an overhead line electrification scheme and produce a common set of data is an admirable one.
Together with software company DHP11 and using the skills of engineers who will eventually use the tool, an XML (Extendable Markup Language) file is built up as the project moves through the design life cycle. This enables high levels of integrity of data, reliability of design and responsiveness to evolving design requirements. It removes a lot of duplicated data activity, while allowing extracts of the data to be taken off and used by the various parties when it is needed.
The whole electrification design can be seen as a single asset base. Incorporated in this is the capture of all the technologies, (including existing asset information where it exists), which means a complete data set for the project can be created. The data set can be used to produce a very reliable picture of all the proposed installations and additionally include all the associated information for each structure, so as to compile a total visualisation of the route that is to be electrified.
The data can then be interpreted to build 3D models, undertake engineering calculations, order materials or do whatever is required at the relevant stages of the project. As each element of the planning work is completed, so the data set is updated to reflect what has been decided, which everyone can then see. The final version before the main construction work begins is used to complete the materials list and procurement specification.
Another significant advantage of this technology is that the need to disrupt the live railway for the installation of OLE is significantly reduced.
Information contained
Much of what an electrification scheme is made up of is obvious, but it is surprising to learn just how much information is required. For a start, every overhead structure or gantry is different even though they are all made up of standard parts.
Data required for every installation includes: foundation type, foundation depth, distance from running line, relationship to other lines, catering for switches and crossings, whether on level ground or an embankment or in a cutting, whether to be fixed to a retaining wall and how high that wall will be, how to locate on bridges / viaducts, proximity to any obstruction such as cable route or drain, existence of level crossings, expected wind loading, even the basic single mast, portal, cantilever, headspan decision.
Add to this the standard requirements for feeder stations, track sectioning cabins, autotransformer feeders and neutral sections, then one begins to see what a complicated exercise this can be.
Once the main decisions have been taken, it is usual to undertake trial borings to confirm the ground conditions. An increasing requirement in the design process is to plan the electrification for optimised possession opportunities required for track and overhead line maintenance. An example would be on a four-track railway whereas in the past, a single portal might be across all four lines, this now may change to have two twin-track cantilevers, thus enabling two lines to be closed with two remaining open for traffic. The use of standard parts sounds good but, with all the permutations, these number well over 1,000.
With each data set comes all the relevant information so that each structure can be viewed as a complete entity. The use of BIM (Building Information Management) techniques enables the sharing of data between disciplines and design stages. The resultant design is agnostic to any one supplier so as to allow many suppliers to bid for the construction contracts.
Usage to date
All this sounds great in theory, but does it work out in practice? The Atkins design philosophy has been tried out on part of the GW project working in conjunction with Amey as the prime contractor, on the NW electrification working with Carillion on the Manchester Victoria to Stalybridge and Bolton sections, with VolkerRail for Blackpool to Preston, also for pre-work on the MML scheme and will be used now that the project has re-started.
It is still being assessed for practicability and how best to ensure the effective distribution and updating of information as the work progresses. Essentially, TADPOLE is a GRIP 3-5 tool but capable of extending up the GRIP (Governance of Railway Investment Projects) ladder as design transforms into reality.
The design element is not linked to any particular method of contractor or supplier. Sometimes Network Rail chooses to manage projects with its own internal expertise, on other occasions it might elect to appoint a turnkey contractor with responsibility for the entire project. The aim of TADPOLE is for it to work with any combination of supply choices. Although Atkins owns the design tool, it does not own the input and output data contained, this being freely available to all.
Resourcing the project
The dearth of electrification projects during the late BR period has been mentioned. Supporting the ongoing development of resources is important if the predicted ongoing electrification programme is to enjoy better success.
Atkins has recruited many graduates and young engineers to bolster the discipline and TADPOLE is making it easy to understand and engage with the engineering. It removes much of the manual work and reduces the chance of error, yet remains driven by engineering principles.
To date, Atkins has 60 UK-based people in its OLE team, including 15 apprentices, as well as 22 engineers based in India and 40 in Scandinavia. Clearly, TADPOLE is a tool that is not confined to the UK and will be employed on overseas contracts when appropriate.
Ongoing development
At present, the tool is geared around office- based design activity, but with the data available it has potential for much greater application.
An industry body has been established to explore the next steps for digitising electrification – the Railway Electrification Delivery Group (REDG), which comprises the Data Exchange Working Group. Atkins has a role in the first and chairs the second with the whole thrust being to share knowledge and expertise.
TADPOLE can enable further efficiencies by allowing digital information to be used by frontline staff out on the ground carrying out installation
or maintenance work. Transporting the data on to iPad, tablet or other portable smart devices is an obvious next step, but this will require a discipline to keep the data up-to-date and for a routine to be in place that all parties follow so that accuracy and consistency is maintained.
The installation of structures, droppers and overhead wiring has been made more efficient by the advent of the High Output Plant System (HOPS) electrification construction train, but it is still largely a human-controlled movement.
Is it just possible to load the design and route data into the train so that it stops automatically at the right place where drilling or erection is to take place? Maybe a step too far at the present time but, with digital technology, all things seem to become possible.
This design initiative is very much part of the Digital Railway programme, although it is not high profile. Once success is assured and usage becomes commonplace, then it will take its place alongside ERTMS, TMS and the other elements of this step change in railway technology.
Thanks to Ben Dunlop, Paul Rowlands and Francesca Buckley from Atkins for explaining the TADPOLE service.
Written by Clive Kessell
