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Case Study

From CAD User AEC Magazine  Vol 15 No 01 - JANUARY 2002

Mapping RailTrack's assets on the UK West Coast Main Line using Cyra's 3D scanning technology.

I must be one of the few journalists consistently writing favourable stories about RailTrack - although with Stephen Byers recent performances the company is rapidly assuming the status of underdog - to be loved by the Great British family of animal lovers. It didn't stand me in good stead with Richard Branson, though, as attempting to get to Birmingham International direct by rail for CIM 2001, I found that the direct train, getting me to NEC in time for the first important meeting was late - 24 hours late, in fact - as it had been cancelled. Richard, bless his heart, ignored the fact that I might never want to use his trains again - it wasn't the only  hilarious incident on the journey - and sent me a couple of vouchers for my next two journeys on Virgin Trains. On one of his brand new trains, I chatted to a pretty hostess, arms laden, waiting for the train to arrive at a staion, so she could replenish the bar at the other end of the train - it appeared that the composition of the train prevented undue passage from the first half to the rear.

RailTrack, or whatever format they may appear in in the future, need all the help they can get, as like it or not, an efficient railway system could still remain the most effective way for getting round the country if it was handled properly - and short term expediency should always be surrendered to long term investment plans - whatever the cost.

So, life goes on, and the company continues to invest in management of its' assets, maintaining its' track, installing new systems and safety procedures, whatever the Government, and the rest of the country may think. As part of this, the seemingly mundane task of listing what you have actually got before you can decide what to do with it, can create an additional costly enterprise unless handled correctly. RailTrack has, therefore, brought in the most competent help to accomplish the task.

Background to the Problem
The UK rail system is split into a number of mainlines. As part of a strategic maintenance campaign, all rail assets are being systematically located, identified, and stored in an asset register. For electrified over-head line gantries, this asset data is supplemented by accurate dimensional and coordinate data that enables overhead line engineers to plan the maintenance and design new, complementary, systems. RailTrack commissioned ABA Surveying (UK) to carry out the nine-month dimensional and asset survey (with accuracies of 10-15mm) for 1500 gantry structures on the West Coast mainline. ABA started the project in September 2000 with total stations using a two-person survey crew, as well as a two-person safety crew, but found the overall process too slow to meet the project schedule. Survey completeness and proper survey QA (missed points or incorrect feature code assignment) were major problems, as the survey crews naturally found it difficult to work with frequently passing trains. Returns were routinely made to specific gantries for resurvey - a major undertaking. It requires organizing permission to access the track, employing safety personnel, driving to a distant site, carrying the equipment for up to a mile and then trying to sort out what went wrong. One mistake could take as much as 4 hours to find and rectify. Attempts to survey with a standard reflectorless EDM were also unsuccessful due to material and weather conditions, and due to difficulty in establishing exactly where a measurement was being taken. To overcome these problems, ABA switched to 3D laser scanning in February 2001, electing to use a Cyrax 2500 and Cyclone software.

Project Workflow
Each structure was captured by a single scan that included pre-surveyed targets. With a scan density of 5-10mm and the high accuracy and small spot size of a Cyrax 2500, dimensional measurements could be extracted directly from point clouds in Cyclone without doing any modelling. Scan targets were co-ordinated using a reflectorless total station and related to fixed survey stations along the route.These target positions were used to register scans to RailTrack’s Project Design Grid. Key locations (ends and corners) on each gantry were selected within a scan cloud, labeled according to a pre-defined coding system, and stored in an ASCII file. These digital files were sent to RailTrack for inclusion in their asset database. Office work was carried out concurrently with fieldwork. With Cyrax, crew size and initial field time were the same as those using conventional methods, but, because of the completeness of the survey that was able to be undertaken using such methods, there was no requirement for further site revisits.

The overall result: a project that was completed on schedule with a 50% man-hour savings. A 2 person Cyrax crew, working with a 2 man safety crew completed ,500 scans in 100 days. In  addition to that, the crews were able to work in a less hazardous environment, putting up the scanners apart from the gantries, instead of climbing all over them to take measurements, and improving the safety aspect considerably.

Cyra Technologies has been involved in a number of projects throughout the UK, some of which are of interest to many people. They are just about to start another project for English Heritage, who wish to survey Fountains Abbey, with a view to arresting the natural decline of the structure beyond its' current state (it is already a Mediaeval Ruin!) Previous attempts at photogrammetry on the site have proved unacceptable, but the expertise and accuracy of Cyra's technology appear to be more suitable to the particular problems that have previously arisen. We are keeping abreast of the developments with both English Heritage and Cyra, and will bring you the results of the survey as soon as they are available - and views on how the data will be put to best use!

I must be one of the few journalists consistently writing favourable stories about RailTrack - although with Stephen Byers recent performances the company is rapidly assuming the status of underdog - to be loved by the Great British family of animal lovers. It didn't stand me in good stead with Richard Branson, though, as attempting to get to Birmingham International direct by rail for CIM 2001, I found that the direct train, getting me to NEC in time for the first important meeting was late - 24 hours late, in fact - as it had been cancelled. Richard, bless his heart, ignored the fact that I might never want to use his trains again - it wasn't the only  hilarious incident on the journey - and sent me a couple of vouchers for my next two journeys on Virgin Trains. On one of his brand new trains, I chatted to a pretty hostess, arms laden, waiting for the train to arrive at a staion, so she could replenish the bar at the other end of the train - it appeared that the composition of the train prevented undue passage from the first half to the rear.

 RailTrack, or whatever format they may appear in in the future, need all the help they can get, as like it or not, an efficient railway system could still remain the most effective way for getting round the country if it was handled properly - and short term expediency should always be surrendered to long term investment plans - whatever the cost.

So, life goes on, and the company continues to invest in management of its' assets, maintaining its' track, installing new systems and safety procedures, whatever the Government, and the rest of the country may think. As part of this, the seemingly mundane task of listing what you have actually got before you can decide what to do with it, can create an additional costly enterprise unless handled correctly. RailTrack has, therefore, brought in the most competent help to accomplish the task.

Background to the Problem
The UK rail system is split into a number of mainlines. As part of a strategic maintenance campaign, all rail assets are being systematically located, identified, and stored in an asset register. For electrified over-head line gantries, this asset data is supplemented by accurate dimensional and coordinate data that enables overhead line engineers to plan the maintenance and design new, complementary, systems. RailTrack commissioned ABA Surveying (UK) to carry out the nine-month dimensional and asset survey (with accuracies of 10-15mm) for 1500 gantry structures on the West Coast mainline. ABA started the project in September 2000 with total stations using a two-person survey crew, as well as a two-person safety crew, but found the overall process too slow to meet the project schedule. Survey completeness and proper survey QA (missed points or incorrect feature code assignment) were major problems, as the survey crews naturally found it difficult to work with frequently passing trains. Returns were routinely made to specific gantries for resurvey - a major undertaking. It requires organizing permission to access the track, employing safety personnel, driving to a distant site, carrying the equipment for up to a mile and then trying to sort out what went wrong. One mistake could take as much as 4 hours to find and rectify. Attempts to survey with a standard reflectorless EDM were also unsuccessful due to material and weather conditions, and due to difficulty in establishing exactly where a measurement was being taken. To overcome these problems, ABA switched to 3D laser scanning in February 2001, electing to use a Cyrax 2500 and Cyclone software.

Project Workflow
Each structure was captured by a single scan that included pre-surveyed targets. With a scan density of 5-10mm and the high accuracy and small spot size of a Cyrax 2500, dimensional measurements could be extracted directly from point clouds in Cyclone without doing any modelling. Scan targets were co-ordinated using a reflectorless total station and related to fixed survey stationsalong  the route. These target positions were used to register scans to RailTrack’s Project Design Grid. Key locations (ends and  corners) on each gantry were selected within a scan cloud, labeled according to a pre-defined coding system, and stored in an ASCIIfile. These digital files were sent to RailTrack for inclusion in their asset database. Office work was carried out concurrently with fieldwork. With Cyrax, crew size and initial field time were the same as those using conventional methods, but, because of the completeness of the survey that was able to be undertaken using such methods, there was no requirement for further site revisits. Theoverall result: a project that was completed on schedule with a 50% man-hour savings. A 2 person Cyrax crew, working with a 2man safety crew completed ,500 scans in 100 days. In  addition to that, the crews were able to work in a less hazardous environment, putting up the scanners apart from the gantries, instead of climbing all over them to take measurements, and improving the safety aspect considerably.

Cyra Technologies has been involved in a number of projects throughout the UK, some of which are of interest to many people. They are just about to start another project for English Heritage, who wish to survey Fountains Abbey, with a view to arresting the natural decline of the structure beyond its' current state (it is already a Mediaeval Ruin!) Previous attempts at photogrammetry on the site have proved unacceptable, but the expertise and accuracy of Cyra's technology appear to be more suitable to the particular problems that have previously arisen. We are keeping abreast of the developments with both English Heritage and Cyra, and will bring you the results of the survey as soon as they are available - and views on how the data will be put to best use! CU

Case Study

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