On Track for Rolling Stock Refurbishment

Faced with outdated and shabby rolling stock, how do you go about refurbishing and redesigning train carriages, to include accessibility for all passengers? The first step is to find out the exact dimensions of the carriages, before considering what design improvements to implement.

One of our clients realised that the most cost-effective, fast and accurate method of capturing the measurements of their rail carriages was to use Physical Digital’s 3D scanning services.

 3D measurement of rolling stock

For over a dozen years, Physical Digital® has been capturing highly accurate data from items between <10mm and 20m using the GOM ATOS Triple Scan optical measurement systems. The accurate, repeatable and traceable data we provide enables clients to improve designs and reduce product errors, making us a perfect fit for our railway client.

Our expert engineers were appointed to 3D scan rolling stock, including the 319 Passenger Train, a dual-voltage electric multiple unit train, the MKIII commuter carriage and a Sleeper carriage. In order to achieve the aims of the client, we carried out internal and external 3D scanning and photogrammetry on the existing carriages. To view the process of 3D scanning this rail stock, click here.
The initial stage of the 3D scanning of the rail stock involved our highly trained engineers carrying out photogrammetry on the exterior and interior of the carriages. This enables them to precisely and accurately triangulate the position of reference points, using the ATOS TRITOP Photogrammetry system. Coded reference markers are used to orientate the images together, which subsequently position the un-coded markers in a point cloud. Calibrated optical scale bars are used to define the relative size.

The optical scanning system used the photogrammetry point cloud to calculate its position on the rail carriage. The GOM Triple Scan’s blue light and high resolution camera projected a phase shifting fringe pattern onto the surface of the rail stock to produce a high-resolution point cloud by capturing several images and calculating millions of points.


Fully portable scanning systems
3D scanning was carried out in the train yards alongside other carriages undergoing maintenance and repair. This meant that there was the risk of disruption to our project, however our fully portable 3D scanning systems enabled us to complete the scheme within the timescales, which would have been impossible with other measurement systems.

Once 3D scanning was completed, our expert team used GEOMAGIC and GOM Inspect Professional Software to align, smooth and thin all meshes to create 3D models of the rolling stock. This was then exported into an .STL file for our clients. The aligned meshes for all surfaces were delivered to the client for them to recreate the rolling stock as 3D models to facilitate the required accessibility upgrade and train redesign.

To find out more about the 3D measurement services we provide, contact us on 01483 750200 or email