RAIL SURVEYING
If you have a particular, say, signal box, you can attach all sorts of information to it: maintenance information, where there’s been faults, any kind of changes that need to made.
“That can be attached, and the complete file passed onwards to someone else with the same footprint. It’s a very accurate way to communicate between Network Rail cen- trally, the devolved companies, and the TOCs, as they too need to understand what work is going on, what role they play in it, and how they can get involved. They will have a much closer relationship with Net- work Rail’s local devolved companies in the future.”
Most of Network Rail’s ‘maps’ are based on its generic systems at the moment, which it hopes to integrate using Ordnance Survey. Especially important for those in the rail industry is the OS MasterMap Topography Layer.
Clark said: “That’s our highest level of ac- curacy. It’s intelligent data, not just a dumb picture.”
Leaves on the line Another aspect of survey data that comes in
particularly useful for railway maintenance is using it to monitor encroaching vegeta- tion and trees overhanging the line.
Clark explained: “They have our imagery layer, and our imagery layer is orthorecti- fied, which means it fits exactly over the topography layer.
“Normally, if you take pictures and try to overlay them, then because of the curva- ture of the earth it wouldn’t fit on top – you couldn’t put, say, Google Maps over topog- raphy because it doesn’t match, but ours matches perfectly.
“That means Network Rail can see areas where there is lots of vegetation at the side of the line and where there are trees, and maintenance can be planned around it.”
Addressing the issue
Another use of the data is in keeping resi- dents informed about upcoming and on- going engineering and construction works (see box-out).
Network Rail has been particularly keen to do this, and its commercial team has insti- tuted a process whereby Ordnance Survey address data is overlaid on top of the to-
pography data, which makes it far easier to work out which households need to be contacted to be informed about noisy or disruptive works.
Effective use of this process has cut down complaints to Network Rail, Clark said, adding: “People tend to feel better about a project when they are informed properly about it.”
Of course, Network Rail and its contrac- tors are also responsible for some major changes to the landscape itself, and there are arrangements in place for it to notify Ordnance Survey when it makes changes to the nation’s topography.
Clark said: “We have arrangements with a number of organisations whereby we take their data when they’ve made changes to the landscape, and that’s integrated into ours. There is a pro- cess for us to do that, because we have to establish a high level of accuracy, and checks are made.”
Visit
www.ordnancesurvey.co.uk Shirley Clark
FOR MORE INFORMATION
For more than ten years ABA Surveying has been helping the Thameslink Programme to create one of the largest scan survey databases of any rail project in the UK, as the company’s Alan Barrow explains.
T
he Thameslink Programme (TLP) route is uniquely dif-
ficult to access for surveying pur- poses. It runs through tunnels and on viaducts and covers more than 100km of track through the centre of London.
Laser scanning has enabled ABA surveyors to capture vast amounts of survey data in a fraction of the time that traditional methods would have taken – and all to mil- limetre accuracy.
As part of its work, ABA Survey- ing was commissioned to scan and produce a 3D surface model of a class 319 train cab seen here giv- ing a driver’s eye view.
What started as a P-Way track and trackside survey ten years ago is
now an all-encompassing hymn sheet that the multi-discipline de- signers can sing from with confi- dence. Witness the reconstruction of Blackfriars, where the demands on the survey could not have been more complex.
High-speed data capture, incred- ible detail and millimetre accuracy are just a few of the qualities ABA Surveying has brought to the TLP project by the application of 3D scanning.
FOR MORE INFORMATION
T: 01483 797 111 E:
alan@abasurveying.co.uk W:
www.abasurveying.co.uk
74 | rail technology magazine Dec/Jan 12
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