Reducing the cost of running Britain’s railways is a continuing process, and one that the rail engineer has covered on a number of occasions. All aspects of both maintenance and renewals are coming under the microscope as Network Rail and others look for any opportunity to increase efficiency. This month, the spotlight falls on the cost of replacing rails, and Pandrol, the leading manufacturer of rail fastenings, has been developing a new product to help keep costs down.
The Pandrol “Re” system of track fastenings has been designed to achieve savings in manpower during the re-railing process. It uses innovation to drive track delivery programmes towards greater yardage, reducing whole life costs through a major improvement in efficiency. The new system also improves the longevity of rail fastening components on older types of concrete or steel sleepers .
Using recent major improvements in technology, the number of individual components has been reduced from five per rail seat to three. The two-part insulator concept, that was first developed for the Pandrol Fastclip system, has also been incorporated.
In the new “Re” system, the rail pad is supplied with the side post insulators already attached, reducing time and labour when laying out and installing the components on site. Dividing the insulator into two parts gives greater component life and allows the separate parts to be made from either the same or different materials to further fine-tune track performance. Careful selection of the actual material used can also improve rail threading and clipping rates, leading directly to reduced manpower requirements and improved yardage.
The design of the “Re” clip takes advantage of a new manufacturing process, patented by Pandrol, known as “Intelligent Cold Setting”. Clips are individually loaded into a press fitted with sensors capable of measuring their mechanical properties. These measurements are used, in real time, to calculate the optimum amount of force that should be applied to produce a clip with the required geometry and material characteristics, and the peak load applied by the press is controlled accordingly. With modern transducers, computing, and control systems, this whole process can be completed in a few seconds with no manual intervention so that each and every clip is manufactured to give the best possible performance. In practice, this new technology allows the size of the clip to be reduced whilst retaining high toe-loads.
“Re” system clips are also supplied with toe insulators already in place, again reducing installation time and the number of loose components on site.
Red-duction in components
Assuming the need for a 7.5mm maintenance pad, the current assembly of components per rail seat used for replacement of clips, pads and insulators on F27 concrete and W400 steel sleepers comprises two e1809 clips, two 724a orange insulators and one 7.5mm grooved rubber rail pad. This gives a total of five components per rail seat, or ten components per sleeper.
In contrast, replacing the above assembly with the Pandrol “Re” system requires the use of two Re1609 clips complete with toe insulator and one composite 7.5mm rail pad complete with side post insulator – a total of three components per rail seat or 6 components per sleeper.
This means that there are two fewer components per rail seat, a significant saving in the time needed for storage and handling. Having the composite 7.5mm rail pad pre-attached to the side insulators makes placing the assembly quicker and more accurate, and rail threading is easier using a recently developed technique for captive fastening systems evolved for the Fastclip system.
Re-ceiving the rail
The single composite rail pad is curved to enable easy placing of the pad into the rail. The curvature of the pad creates an “open-jaw” of the side insulators and an inclined plane to receive the rail, and the pad is flattened by the weight of the rail as it is threaded into each rail seat. The insulators close on to the foot of the rail as the pad is flattened, self-centring the rail in the rail seat and reducing the time needed to centralise the rail in its seat during the threading and clipping process.
Work is under way to develop an automated installation method of the composite pad as a second phase of the adoption of the “Re” System, and this will lead to still greater efficiency on-site.
Re-railing at Bawtry
The first installation of the Pandrol “Re” system took place in April 2011 on Network Rail tracks near Bawtry, South Yorkshire. The site was on the up fast line, with an approximate 3000m radius curve, 150mm cant and line speed of 125mph. Sleepers were predominantly F27 but some F40s had also been installed at an average of about one in six.
Work consisted of re-railing two 709ft lengths of Continuous Welded Rail (CWR). Within this length, 212 F27 sleepers (on the high rail only) were to be fitted with the new 14229 composite rail pads and Re1609 clips.
Work commenced with all existing clips being removed. The rails were then threaded out of the rail seats using a McCulloch rail threading machine. New “Re” components were laid out into position on the sleepers from a rail trolley located on the adjacent track. Once the new pads were placed into the rail seats, the new rails could be threaded into the sleepers. Vortok Stressing Rollers were positioned fifteen sleepers apart and the rails were welded at each end, then stressed in the middle. Clipping up was completed using standard Panpullers.
The contractors required very little product training as the “Re” system is not very different from the usual components. However, it was very evident that, while re-railing the other rail using traditional components was taking place, more than ten people were used for installing components – four or five (two to three of them on their knees) were employed just placing insulators. When installing the “Re” clips, these five men were not required. In general, all that is required to install “Re” after the components have been distributed is a team of two or four men on Panpullers and one or two men placing clips into the housings (dependant on the length of the installation).
Following the first installations on the network, Pandrol organized a road show tour of Network Rail maintenance delivery unit (MDU) depots. Most were visited during the autumn of 2011 and staff were given a product briefing and a demonstration using a short track panel. The Pandrol team, supported by Vortok International, explained how the “Re” system works from the initial installation through to the first rail stressing in conjunction with the VSR system of stressing rollers.
The road show team completed 26 demonstrations and travelled over 2,800 miles during 6 separate weeks starting at the beginning of September and finishing by the first week of December. During this period, Pandrol was investing in, and commissioning, the high volume tools needed to meet the forecast demand.
The release of high volume components, following commissioning, started in January and has accelerated during the spring of 2012. Site experience is now being widely reported from across the UK network. Savings in time and manpower have been realised on sites which have switched from existing “e” clip assemblies. One particular site in the northwest of England has reported: “I have heard back from the Carlisle section manager, who replaced the existing fastening system with the Pandrol “Re” System – he managed a quarter mile in eight hours, which is a vast improvement on current methods.”
The recent re-railing project at Micheldever in Hampshire reported similar results by re-railing over one mile of track during one weekend possession. The track was stressed over a separate weekend and the operation was so efficient that time lost in the early part of the possession was recovered during the clipping operation.
These savings from the implementation of Pandrol’s new “Re” system are set to be repeated across the network, contributing to the industry’s efficiency improvement programme.