Access and crossings

Lucy Hamilton, KOREC Group 

Tackling access points on the Western routes

WITH the publication of CP7¹, Network Rail has underlined the importance of running a safe, reliable and efficient railway while working as effectively as possible and achieving ‘more for less’. It is these factors that underpin how each access point job is tackled on the Western route.

Output

Driving efficiency through innovation is an important factor in delivering Network Rail’s aims. Particularly, since in the last two years the volume of work has more than doubled due to the introduction of technology, as well as the quality of the work, alongside changes in budgets and control periods. The Network Rail Construction Services Off-Track (Western) team is now the sole deliverer of access points on the western route, and this has seen its CP6 budget for 15 access points per year more than double to a current target of 35.

With the publication of CP7, Network Rail has underlined the importance of running a safe, reliable and efficient railway while working as effectively as possible and achieving ‘more for less’.Aware of current labour costs, it was felt efficient use of time on-site and labour could result in significant ‘more for less’ gains. One of the most time-consuming challenges faced was the accurate positioning of the rail access platforms. Setting out the drawings more accurately, could overcome many of the site challenges that slowed the job and also deliver it at a higher quality.

Workflow

One of the main challenges faced is that although the top access platform can be installed easily using a gate as a reference point when first arriving on-site, moving away from this reference point slows the process down significantly.

For example:

Set up first landing → bolt the strings on → lift platform to required angle → jack into position → manually measure from existing legs as per design → undo work and repeat.

Consequently, there was no fluidity to the work as those who were putting the screw piles into the ground had to wait for each position to be established manually. It was felt that using GNSS would dramatically increase site productivity.

A solution

It was felt the Trimble Catalyst system would be a solution, alongside centimetre accuracy, TDC600 rugged data loggers and KOREC’s Capture Pro software for rail. For the client it was:

• Simple and usable for teams that are not trained surveyors.
• Centimetre accuracy for additional applications. However, decimetre accuracy would be sufficient for positioning the screw piles. 
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• Reliable positioning across the entire western area from Worcester to Paddington to Penzance. An awareness of dead zones with no mobile signal, the technology works in the background whenever the internet connection goes down, for up to five to ten minutes.
• Reliability under tree canopy, with all the team’s work route based and often surrounded by vegetation. It meant minimal removal of any vegetation around the area of work.
• Portability out in the countryside. 
• Software developed specifically for the rail industry with the inclusion of a safety feature that alerts workers if they stray out of a geofenced area, as well as also providing information for all workers to know exactly where they are on the track.

Additional features such as positioning more pegs for datum/a second check gave the option of plotting measurement points which come up on the map on-site.

Using different colour points as work is completed, enabled tracking ability and ensured avoidance of duplication. If errors did occur, the cause could be identified whether it was insufficient setting-out points, operator error or malfunction of equipment.

Out in the field

While many jobs are fairly straightforward, there are others which require more thought. A recent project at Feltham where an angled platform meant that a positioning error of 2° or 5cms was out on the first walkway could mean a 1m discrepancy at the base and the need to redo the job. 

While many jobs are fairly straightforward, there are others which require more thought. A recent project at Feltham where an angled platform meant that a positioning error of 2° or 5cms was out on the first walkway could mean a 1m discrepancy at the base and the need to redo the job.

Additionally, in order to meet Network Rail standards, the job would have to start at the top to ensure that they were the correct two metre distance from the track but there were no datum points to measure off.

Using this method could see the screw piles placed in the exact location as on the drawing first time whether the job is started from the top, middle or bottom. There would be no need for strings and manual measurements so the diggers can work three to four holes ahead of the installers.

Conclusion

Not only was the ease with which the platform’s piles were accurately positioned important, but an additional benefit of digging smaller holes for the piles meant less concrete was being used resulting in a reduction of carbon, as well as materials.

Other applications, including drainage mapping and marking boundaries, could also mean that costly disputes with landowners can be avoided. It is a method that could be beneficial for many applications. 

Lucy Hamilton, KOREC Group

www.korecgroup.com

@KORECGroup

1 See https://www.networkrail.co.uk/wp-content/uploads/2023/05/Overview-of-CP7-efficiency-initiatives.pdf