Surveyors take to the fast track
17 May 2005
It's a task that once would have required a veritable army of surveyors armed with an array of measuring instruments.
But these days a comprehensive survey of Victoria's country railway assets needs no more than a train engine armed with two high-speed digital cameras.
Part of a sophisticated mapping system, the cameras are able to record an image every two metres as VicTrack's EM100 train zips along the railway lines at speeds of up to 100 kph to create a comprehensive visual database of the state's railway assets.
The Rural Rail Asset Survey - conducted by Geomatic Technologies Pty Ltd, of Melbourne - is part of a broader initiative aimed at creating a complete database of the state's rail infrastructure. It kicked off in late 2002 with a 10-month project mapping train and tram infrastructure assets within the region.
Paul O'Halloran, manager of standards for the public transport division of the Victorian Government's infrastructure department, says the asset survey - the rural leg of which began in September last year and is expected to be completed later this year - aimed to build a web-accessible register of rail assets to replace the mountains of documentation that lie in an archive in inner-western Spotswood.
"We've got all these paper-based systems, we've got all these Excel spreadsheets and all these databases. We wanted one single point of access to a database record that contained everything," he says.
About 5000 kilometres of track and more than 400 stations are expected to be surveyed as part of the project.
As well as recording images from a train driver's perspective, the rural mapping project involves sending Geomatic staff to record level crossings from a motorist's perspective and using aircraft to take aerial photographs (of five-centimetre resolution) of stations and other infrastructure that cannot be seen from the track.
Geomatic's business manager, Dave Presley, says that the company's Asset Management Mapping System (AIMS) images are "geo-referenced" as they are collected on the train, with a GPS sensor recording the train's exact location as the image is taken.
"While the camera is running on the train, we're also recording the train's location," he says.
"So we process out the location centreline of the train network, then we link the centreline to each individual frame . . . so there's a co-ordinate associated with each picture."
When the train passes through a tunnel or forested areas and GPS reception is not available, the system relies on a digital compass and a measuring instrument that counts axle revolutions to work out the co-ordinates.
About 10 per cent of the data relating to the rural rail infrastructure - which is expected to total between two and three terabytes - has so far been collected.
Mr O'Halloran said that once the images and information are fed into an assets database, they can be accessed via a web browser using PASS Assets (Privatised Arrangements Support Systems) - an application the department developed that employs GE's Smallworld GIS technology.
About 150 people have access to the system - which includes data for both the metropolitan and rural rail networks - and as well as staff at the Department of Infrastructure they include the state's train operations and maintenance companies.
Mr O'Halloran said the department will make interfaces to other rail and tram-related asset management systems and was also considering developing an interface between the asset database and its electronic drawing management system. This would enable drawings of infrastructure - once they are scanned into the database - to be called up via the same web-browser technology.
He says that in terms of using GIS to map rail systems, "I think we're getting pretty close to being one of the best in the world".
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