The post-war modernisation of British Railways saw the introduction of ‘panel’ signal boxes covering many route miles on busy main lines. Writes David Bickell
These new boxes involved the total equipment replacement of older lever frames or power installations. The schemes were generally delivered by a small number of signalling equipment manufacturers, with much of the work being carried out in-house.
With a nominal life of 25 years, many panel boxes are still in service today 50 years later, although some of the installed kit has been refurbished or replaced in that time. Watford Junction (1963) is due to be decommissioned this year whilst Plymouth (1960) is still going strong.
During the Railtrack era, the use of the Signalling Condition Assessment Tool (SICA) showed that these robust and generally reliable installations could continue in service and there was no point in spending money unnecessarily. Nevertheless, innovation in the control centres took a leap forward from 1985 with the introduction of Solid State Interlocking which replicated the function of relay interlocking. This was followed in 1989 by a visual display unit equivalent of the signaller’s panel.
Investment and cost saving
Engineers were aware that there was going to be an investment bulge of signalling renewals come the twenty-first century. Add in the roll-out of the ERTMS/ETCS overlay and various signalling alterations to increase capacity, not to mention Network Rail’s strategy to centralise control at a dozen or so Rail Operating Centres (ROCs), and it becomes apparent that there are new opportunities for suppliers both large and small.
Future signalling requirements are being met by a combination of re-signalling (all new signalling), re-lock (typically replacement of a relay interlocking with a computer-based version), and re-control (usually replacement of a panel with a workstation in a different location).
Current signalling costs are considered to be too high and a real reduction of 16% by 2019 is the target. Unfortunately, overall costs are going to increase substantially in the short term since the ERTMS/ ETCS kit planned for intercity routes is additional to the existing signaller interface systems and interlockings which will continue to be needed. Savings may be realised only when all trains on the route have been ERTMS fitted and lineside signals removed. Further cost reductions may be achieved when track fitted train detection systems are replaced with wireless train positioning techniques. The latter is the ETCS Level 3 package, provision of which is likely to be highly complex from both engineering and operations perspectives, and isn’t going to happen any time soon.
In the meantime, there is much scope for cost saving innovations out along the lineside. Until recently, signalling technology has changed little, with old fashioned power supplies and multicore cables that are labour intensive to install and test. Evidently there is a niche market here for innovative smaller suppliers that are willing to work in collaboration with Network Rail.
Small yet successful
One such company is iLECSYS (intelligent electrical control systems), a small company employing 65 people at four locations in the UK. It has enjoyed impressive growth, more than doubling turnover in six years to £9.5 million in 2013 and The Rail Engineer recently visited the company at Tring in Hertfordshire.
Peter Dickson, engineering manager of the rail division, explained that iLECSYS acquired his own company in 2002. This had specialised in
the machining and assembly of well engineered, affordable, insulated electrical enclosures, and the manufacture of components for the oil and gas industries. Peter has an interest in railways and astutely believed that there might be parallels with the highly disciplined and safety critical oil and gas industries.
Given the diverse nature of Network Rail’s signalling investment programme, the iLECSYS approach to the railway industry could not have come at a better time. It is quite a challenge for a small company to become a supplier to Network Rail but the company ensured that it was off to a good start by setting itself certain goals – supporting customer initiatives; providing a fast, practical vehicle for innovation; delivering cost reduction through reduced maintenance and supporting zero harm.
Peter acknowledges the help of the Rail Alliance, a networking organisation facilitating collaboration and innovation, in putting iLECSYS on the map. Much hard work followed, leading to iLECSYS becoming a registered supplier under the Link-up qualification scheme. Needless to say, the company has quality management systems in place and has been successfully audited by Network Rail.
Today, iLECSYS collaborates with Network Rail’s infrastructure project teams and signalling technical specialists at Milton Keynes, working
to achieve product acceptance for its products. It has been supplying around a dozen schemes since 2010 including Reading Area Signalling Renewals, Thameslink and Stirling.
The company specialises in the configuration and supply of products based upon fibre reinforced plastic (FRP). The commonly used fibres are carbon, glass and aramid while the most popular resins include polyester, vinyl ester and epoxy. FRP is named after the fibre used, so glass fibre reinforced polymer is GFRP.
First developed in the mid 1930s, the use of GFRP has grown from a few components to complete structures. It is very light, has a high strength to weight ratio, is water-proof and chemical-resistant, and can be moulded into almost any shape.
GFRP’s electrical insulation properties make it ideally suited to the production of ‘composite electrical enclosures’. In railway speak, this translates to fibreglass disconnection-boxes, fuse boxes and signalling location cases. Recently, the introduction of Class II power into railway signalling has promoted even more use of GFRP.
Traditionally, signalling power supplies have consisted of a Class I, 650VAC feeder cable. Class I refers to a system that has an earth return so that any fault in a particular location will divert stray current to an earth point, thus protecting someone from electric shock. This is a costly system requiring robust earthing arrangements at all locations and a three-core power cable with earth return conductor.
Because of the way that cable design takes into account earth return currents, it is possible for the size of the earth return conductor to be larger than the individual phase conductors. As cables are only manufactured with equal sized conductors, this can mean that the cable is sized to the larger earth conductor, thereby using a third more copper than is necessary to carry the supply.
Safety is a further concern, given the many cable thefts in recent years. With theft and vandalism, there is a risk that the earth return system could become compromised leading to death or serious injury.
Enter Class II power supplies. Class II is a system where the individual location is encased and double insulated so that if a fault develops, that fault is contained within the casing and nobody is exposed to electric shock (see issue 98, December 2012).
GFRP switchgear boxes for Class II signalling power supplies are supplied by iLECSYS and these were installed at Reading during the recent Christmas blockade. A further innovation is the provision of a micro switch box, used to create a disconnection facility where a lineside power supply splits between a legacy Class I system and everything downstream of that point which is Class II.
Enclosure boxes can be supplied in a variety of sizes suiting many signalling applications. The latest development by iLECSYS is the GFRP location case which is shortly to be installed at Stafford, London Bridge and Watford Junction. The current signalling location case (‘loc’ for short) is usually made of steel which has a tendency to cook sensitive electronic units in hot weather, necessitating a partial application of a suitable heat reflecting paint. GFRP comes with the advantage of a low heat transfer coefficient.
Aside from signalling applications, GFRP boxes have many potential railway applications including traction third-rail heating panels.
Plug & Play
The concepts and practicalities of signalling ‘Plug & Play’ were expounded in issue 107 (September 2013) of The Rail Engineer. The term has come from the computer industry and whilst ‘Plug’ is correct, ‘Play’ is not apt for a signalling environment since the cable terminations are specific to a particular application and would need to be part of the functional testing routine.
Generally, lineside multicore cables carry controls and indications to/from the signalling centre and the individual cores of the cables are hand terminated onto disconnection links at each end. This is labour intensive and is followed up by wire counts requiring skilled testing staff to spend time on site.
The introduction of plug couplers to signalling cables is not new. The Crewe resignalling of 1985 was undertaken in a tight 6-week summer blockade of the station where all the existing track and signalling was removed and replaced with new. The use of military grade plug couplers enabled clamp lock tail cables to be prepared and tested in advance, and installed rapidly when access became available to the newly installed point work. However, further use of plug couplers at that time was ruled out on the grounds of the high cost of the plug coupler components and concerns about water ingress and failure potential. Nevertheless, the potential labour and time saving advantages were established.
Today, the use of plug-coupled cables is firmly back on the agenda. iLECSYS has a range of plug-coupled disconnection boxes available for clamplock points, point machines, signals, axle counters, level crossing lights, obstacle detectors and much more.
There are many other uses of FRP, both temporary and permanent. Signalling location cases need to be installed onto solid ground with a support platform often needed. With the recent floods causing damage to railway infrastructure, FRP platforms could provide a great solution to raising signalling location cases above flood levels.
Dawlish has been much in the news recently, with the collapse of the sea wall and railway following heavy pounding from storm-driven waves. Just a few hundred metres away, the new station footbridge has remained impervious to the weather throughout – and it is made of FRP.
In the future, rail engineers are likely to increasingly turn to FRP for innovative solutions to a variety of applications.