The often-criticised Great Eastern route from London to Chelmsford in Essex has suffered from overhead line equipment (OLE) unreliability for some considerable time. This is not really surprising as the OLE has its origins in the 1940s as part of the original LNER-engineered 1500V DC system. First introduced from the late 1940s through to the mid-1950s, it was converted to 25kV AC in the early 1960s.
The contact system has proven to be unable to perform on this most heavily trafficked route and both train operating company and Network Rail were under pressure to improve matters.
The basic project requirements called for a comprehensive renewal and replacement of the wiring and associated parts and entailed the use of a designer and manufacturer new to the UK. Phase one of the scheme would cover the old Great Eastern Railway route from London Liverpool Street through busy Stratford and out via Brentwood to Chelmsford. Phase two would be looking at the other ex-1500V system, from Shenfield to Southend.
Technical considerations
Collaborative Project Management Services has been involved with the project since the early days. Managing director Mat Baine took the decision to re-examine the works, review the programme and freshen the scheme approach. It was necessary to think exactly what the scheme was and how to treat the project design and construction process.
Basically the job entailed replacing the old Great Eastern Line equipment with a new bespoke design of Great Eastern Furrer and Frey (GEFF) electrification hardware, all fitted to the ex-1500V structures. Mat emphasised that it was not an OLE renewal and not an OLE project.
The differences between old and new are significant. The old equipment was fixed-tension, the new is auto-tension style. The old required speed restrictions when temperatures reached 25ºC yet the new could operate at up to 40ºC without speed limits. In addition, the old system had very limited electrical clearances with their associated performance risks while the new had none of that.
Further, the old system suffered from high maintenance costs requiring a four-year maintenance cycle as against the new system which was designed to deliver between six and, hopefully, eight-year maintenance cycles. Within those frequencies, the early system planned maintenance required four shifts of work per wire run whilst the GEFF system required only two, reducing six-year maintenance costs by two thirds. The new system is confidently expected to deliver 4.6 years mean time between failure (MTBF) per track mile, as against 0.21yrs MTBF per track mile of the existing installation.
Project elements
An electrification project is more than a contact system erection task. It is formed of many stages, typically: outline design – final design – trial holes and surveys – foundation installation – design – wire runs – small part steelwork – mast installation – boom installation.
Mat has very firm views on the project process and used the ‘plan, do, review’ cycle as the basis of the team’s approach. The team is, in fact, a set of teams, the ‘OLE Project Team’, formed as:
- Advanced works team
- Civil engineering and design team
- OLE team
- Principal contractor team
- Support Teams.
All the above are held together and in-line by the programme manager, centred on collaboration. Within the team there are also ‘non-physical’ elements such as procurement, planning and integration, and possession management.
Mat was keen to explain his thoughts on procurement. He found that the procurement strategy had been very piecemeal and had not given tenderers sufficient scope to look at the longer term and invest time and money in their tenders. The strategy was revised to alter the size and make-up of the scope elements to allow bidders to take a longer view. Where performance has been good, they have been able to offer production economies as part of feeling more embedded in the programme.
As part of the revisit, the project was re-estimated from first principles for the remaining work using internal project cost information. Key challenges in the production of the estimate included:
- Quantifying the staged construction methodology due to the changes in possession access;
- Establishing unit costs for key activities and understanding achievable productivity;
- The quantification of risk when delivering to a revised delivery model (incorporating key lessons learnt).
Foundations can be the Achilles heel of an electrification scheme. By nature, the composition of the ground will be uncertain and a pre-designed foundation may not always be suitable for the location – either too robust or insufficient. Careful investigation allowed the load assumed under generic pile range designs to be re-assessed and generated large savings during installation.
An electrification scheme will require large quantities of diverse materials of high cost and significant handling liability. A review of the locations revealed a varied number of sites and even rented locations in use. With the scale of the programme being reasonably certain and designs predictable, a decision was made to purchase warehousing and rationalise the materials to a store on a single site, accompanied again by significant financial and operational savings. Similarly, a decision was made to purchase site cabins, a necessary requirement under law but also a motivator for staff in the line of better messing and welfare conditions.
Welfare leads to safe working and the project has placed great emphasis on some of the detail in that sphere. A real hazard from working on old equipment is the presence of lead in finishes and, following a detailed risk assessment, it was realised that the gas cutting of old structures carried a risk from the paint. To that end, ventilated masks were provided for the task.
All staff have been encouraged to undertake, and pass, IOSH training and close call notices are part of everyday procedure and practice. Site entrances are notorious for slippery and uneven conditions and another campaign has been to renovate the access points used in the scheme to allow a clean and safe passage. Safety behaviour is not always 100% and a close eye is kept for unsafe acts, followed by suitable counselling.
To sum up the team approach, Mat would quote the old adage: “Smarter, not harder.” One example of that is the practice which attracted Rail Engineer to this project in the first place.
Coasting
The project asked itself the following question, when running an overhead line wire adjacent to an open road, how do you:
A. Keep passengers moving?
B. Keep staff safe from electrocution?
C. Keep on target for hitting planned volumes
The answer that was worked out was: “COASTING!”
The geography, and thus the gradient profiles, of the Great Eastern main line lends itself to gravity being viable as a traction source for trains. The connection then is that staff can work on the OLE, on a multi-track main line, in a safe situation with adjacent roads open to traffic but electrically isolated. They are protected from trains by their workplace and the electrical threat has been placed away where there is no hazard.
Safe working is allowing a viable flow of trains in the Up line while coasting as the Down line carries a normal service with full electric traction facilities. The work on the Down main is without electrical risk yet gaining flexible and productive access and the MEWP (mobile elevated work platform) is based safely on the Up main.
The project is proud to say that it has erected 10 wire runs of approximately 7,200 metres length while working in excess of 16,000 man hours without accident or incident. The performance statistics put the operation into perspective – the project has coasted 700 trains which have rolled for over 3,000 miles!
There has been significant gains for passengers, Network Rail and the train operators with 133,000 passengers moved and over £600,000 saved on replacement buses.
Whilst trains have coasted for many years, and that is a property that rail has as a system characteristic, the planned application of the process is not so common. Careful risk assessment was applied and safety features were assured in the planning process. Operational risk was also considered and again this was assessed to facilitate acceptance of the process.
As well as effective briefing, rail staff need to be properly advised of the condition of the railway and a suite of signs has been erected to clarify conditions, positions and required behaviours. Advance warning is given as the train approaches the lower pantograph sign at permissible linespeed and duly lowers the pantograph. The safe zone to raise the pantograph is identified by suitable signage at the other end of the site. The signalling staff are a part of the process – the signaller has the responsibility to instruct the train driver of arrangements when agreed with a competent person.
A train having to brake or come to a stand is not seen as high risk as there are electrification staff on site and a safe situation to allow re-energisation of the isolated line can be quickly arranged.
In essence, this project has shown that, whilst criticism of electrification engineering works has been made, there is still plenty of room for innovation and smarter ways of working.