New Model Railway
Engineering Director Millan Martin and Principal Digital Engineer Jack Muroni outline Taylor Woodrow’s high-accuracy method of dynamic envelope modelling
When it comes to building new railway infrastructure, getting the basic measurements right is absolutely essential before it can be safely pressed into regular service.
Whether it be new track, bridges, depots or even retaining walls, making assumptions or relying too heavily on data produced at an earlier stage of the design and construction phase can invite the risk of significant gauging or structural issues occurring later.
Making such mistakes or failing to spot them is not just unnecessary, but can be expensive and time-consuming to rectify, which is why leading civil engineering firm Taylor Woodrow has overhauled traditional modelling and measurement techniques to more precisely capture and validate this crucial information.
The company’s Digital Engineering team has taken a technique employed in other sectors of the construction industry and successfully pioneered the use of established 3D modelling software and applied them in the rail sector. This is of particular relevance to the complex interfaces between a train and the infrastructure through which it moves.
These newly applied methods have been clearly demonstrated at the Old Oak Common depot, where Taylor Woodrow has designed and built a new £142 million maintenance facility for Bombardier including an Operations, Maintenance and Control building, containing nine maintenance roads, a jacking road, and 33 stabling sidings to accommodate half of the Elizabeth line’s fleet of Class 345 Aventras.
The trains are currently being delivered to the site by manufacturer Bombardier. The facility will become fully operational before the line’s central section beneath London opens in December.
But before any trains could be accommodated, Taylor Woodrow was required to provide firm assurance that they would not collide with any maintenance gantries.
In order to verify the measurements of the steelwork, the company asked its Digital Engineering team to devise a more accurate method than using the classic manual techniques traditionally associated with such tasks, including building a plywood model replica, and using a tape measure and check sheets.
The new and improved solution for quality assurance was to use a Leica ScanStation P40 by Leica Geosystems scanner to build an accurate 3D model of the gantries and surrounding elements to produce a ‘point cloud’, the raw data from which was then processed using Leica Cyclone REGISTER 360 software to tie the data in with a local coordinate system.
A 3D model could then be created to compare the new measurements with original 3D models created at the design stage, that had been made using Bentley MicroStation 3D computer-aided design (CAD) software.
To check for potential clashes, a 3D model of a Class 345 train was also provided to
Having a model built on digitally scanned data is a far more accurate and reliable way of finding discrepancies. Jack Muroni, Principal Digital Engineer, Taylor Woodrow
Taylor Woodrow in Catia CAD format to import into the new 3D model.
A software program called Verity, produced by Clearedge3D Ltd (a subsidiary of Topcon), was then employed to compare the existing model, based on manually captured data, with the Leica-scanned point cloud model. All the information was imported into infrastructure modelling software Bentley MicroStation to produce the drawings that would verify that the new trains wouldn’t foul any infrastructure.
Taylor Woodrow Engineering Director Millan Martin explains: “We have taken software that’s already available and applied it to the complex environment of rail. I have seen similar techniques used to construct buildings and civil structures, but this was the first time they’d been used in modelling the difficult geometries of rail.”
Principal Digital Engineer Jack Muroni adds: “The traditional method for gantry measurement would be to take measurements by hand every five or ten metres. It is a painstakingly slow process and it would be very difficult to measure every single beam because there is lots of steelwork in the way.
“It is very important to get this right because if someone has made a mistake and the original model is inaccurate then it causes embarrassment and can be very costly to fix. Having a model built on digitally scanned data is a far more accurate and reliable way of finding discrepancies.”
Two further examples of the digital engineering team applying the same innovative solutions to validate new pieces of rail infrastructure are at Filton Bank, where a two-track section of line is currently being doubled to four in order to increase capacity between Bristol Temple Meads and Bristol Parkway, and at Whitechapel, where a new interchange station is being constructed for Elizabeth line, London Underground and London Overground services that will open in December.
At Filton Bank, the partial deviation of a new retaining wall had been detected due to unequal settlement of backfill. Having carried out remote monitoring of the wall to better understand the behaviour of the earth movement, it was determined that the wall was stable but that a new, more up-to-date 3D model would be required to design the best fit and alignment for coping stones along the top.
Taylor Woodrow again used its digital expertise to create a 3D model using a Leica ScanStation P40 by Leica Geosystems and a digital camera to produce point cloud data.
This data was then processed using Leica Cyclone REGISTER 360 software, in which the Leica ScanStation P40 scan data and photogrammetry (taking measurements from photographs) data was merged and tied into a local co-ordinate system. It was then exported to MicroStation to create a final 3D model of the wall, while PointCab Data Module software was also used to highlight disparities between the design and as-built data sets for the wall.
Meanwhile, at Whitechapel, discrepancies had been found between the point cloud and Bentley MicroStation models used by the manufacturer of cladding for a new bridge and raised station concourse being constructed above the London Overground, Elizabeth line and London Underground platforms.
It was deemed necessary by engineers to remodel the bridge where information was found to be missing, and then use point cloud data and data gathered using traditional topographical methods to make a comparison between the design and as-built data sets.
Muroni says: “This process is quite new to rail and it takes people time to develop the right expertise. You need to understand how to use this software and the large amounts of data it generates which is a big challenge, but successfully completing these three complicated projects enables us to go to clients with confidence that we can give the right answers.”
Taylor Woodrow is now planning to deploy this suite of digital solutions more widely, and is steadily building a portfolio of projects where its benefits can be clearly compared with traditional methods.
Although unfamiliar to the rail sector, Martin believes it is only a matter of time before it becomes the standard way to model and validate infrastructure after construction: “There is a cultural issue here, because I think some clients are still unsure of the software, but as soon as they see how valuable it is they will want it for their projects too.
Network Rail was very impressed that we could identify the issue of the wall at Filton Bank, for example, and so these things are now being appreciated by clients and really starting to make a difference.
“We now have three good examples, but this is a change of culture so we have to work with the client, and we are telling them to go virtual because we believe this is the best way to work.”