Value for money and driving down costs are two linked themes that are very much the focus of attention at present. The Rail value for money study by Sir Roy McNulty is bringing into sharp focus how cost savings can be made, identifying that the industry can work together more effectively, with an emphasis on partnership. This, coupled with clearer objectives from government and the scope for change that exists, can perhaps deliver the efficiencies that are needed.
Mapping is an area that offers its share of opportunities. We have great maps in this country and they are used by just about every part of the rail industry for many different purposes. Unfortunately, it is this huge variety of different needs that causes their use to be uncoordinated and disparate, leading to inefficiency and higher costs.
Today’s mapping processes are digital throughout – from surveying and data capture to processing, mapping, delivery, visualisation and usage by the end-user. This means that it is now possible to deliver a greater range of mapping products from one aerial survey of the railway asset.
Applying the study to mapping
Amongst the key themes of Sir Roy’s study are the need for greater clarity and better alignment of high level objectives, and more collaboration. Applying these two principles to mapping is a fundamental step to ensure that the greatest potential can be realised from an aerial survey.
In the mapping process, the first key requirement is the preparation of a specification for the work. In many cases, surveys of the network are commissioned on a project-by-project basis. There is nothing wrong with that but it is critical to consider the wider scope and include all the other projects that are planned on that section of line. If all users’ needs can be captured collaboratively then the aerial survey can be specified to meet them. All the different mapping products that they need can be processed and generated from a single instance of aerial survey capture.
A further way of maximising value is to ensure all projects are gathered together regionally where a survey is planned. This can often result in the rail asset between project areas being captured as part of the process, delivering another cost-saving.
Innovation is another important area, achieved by presenting survey and mapping providers with a wide set of clearly specified requirements. They will have to ensure the best use of the most up-to-date survey technology to deliver solutions to the clients under competitive tender.
Rich data source
The options today are far wider than simple aerial photogrammetry or land survey using a traditional instrument. Numerous digital sensors such as high-resolution imagery, laser scanning (LiDAR), hyperspectral or thermal imaging, video and other geophysical sensors can be deployed from aircraft or on-track.
Sensors can often be used in conjunction with each other to generate a rich data source from the survey flight. For example, a common sensor combination is the capture of LiDAR, high-resolution imagery and video data. A survey of this type will result in several raw building blocks of spatial data that can all be processed to generate the different products required for the project.
Central repository
Sir Roy McNulty’s report emphasises that stronger incentives could be introduced to align interests towards delivering lower costs. For mapping of the rail network, this can be realised with a far better reuse of survey and mapping information. The data gathered for one project, or a group of projects, should be made available to other stakeholders. A central repository of survey data and spatial building blocks of data is vital. This process will generate further value from individual project-based surveys.
Aerial surveys fit extremely well with the fundamental rail strategies of safety, cost reduction, network reliability and capacity. Blom UK has always been safety-focused (as examined in Issue 71 (September 2010) of the rail engineer) and with aerial survey the happy bedfellow is cost reduction. The time and manpower resources needed to plan and deliver protection arrangements for just two land surveyors, gathering traditional survey data on the trackside, are simply not required.
A further partner in this relationship is maintaining the capacity and reliability of the network. Aerial techniques do not involve blockages of the line which can have a service impact on the lines being surveyed. Instead, they remain open and the trains run as normal whilst the aircraft buzzes overhead.
Nothing new
All of this is nothing new in the field of mapping. Seven years ago, the Highways Agency let a nationwide framework contract for LiDAR surveys. This realised the aspirations outlined above – collaboration between stakeholders, clear specifications of requirements, multiple sensor capture using innovative techniques and central storage of data for multiple reuse. It was not perfect but was certainly a step in the right direction.
Blom pioneers this approach for many of the projects it undertakes. On successful appointment, the firm tries to ensure that all stakeholders have been consulted for the work and that any variations or additional needs can be designed into the survey data capture and mapping delivery. A good example of how it achieves this is to review its 2010-11 project on embankments in the south-east.
Case study
Blom was initially commissioned by one of the consulting engineers to carry out a helicopter-mounted TopEye LiDAR and imagery survey of 37 separate railway embankments. All required detailed topographic mapping to design revetment and other geotechnical engineering works. With so many different sites, Blom decided not to survey each one individually but to group the sites by line and capture as much survey data between them as possible.
Using this technique, numerous additional sections of line were surveyed so that the data could be used for future applications. The embankment project was delivered as required and the focus of the Blom team then moved towards finding out what other projects were being undertaken in the areas captured.
A lineside tree survey was identified so additional datasets were provided for use by the team involved. LiDAR is a great tool for this sort of vegetation assessment as the laser data penetrates the tree canopy and ensures ground levels can be accurately mapped. As part of this process, laser ‘hits’ in the tree canopy can be reused to generate useful cross sections showing the proximity of the canopy to the line and thus indicating leaf fall. In addition, the position of the trunk relative to the track geometry is determined, providing a ‘falling tree analysis’.
Work continues to ensure the useful survey and mapping data gathered can be further used on planned projects in these areas.
Host of solutions
Obviously, aerial surveys cannot provide data for all rail infrastructure projects. They do however ensure that land-based surveys involving track access can be kept to a minimum, focussing on small, critical areas. Aerial techniques provide a host of mapping solutions for the teams working on our network.
By demonstrating collaboration, clear leadership, innovation and cost effective reuse of survey and mapping information, a considerable first step towards cost reduction can be made. We can all help score the goals recommended in the Rail value for money study.
Highways Agency contract
Between 2004 and 2011, the Highways Agency procured surveys of its network under a framework contract. This ensured that a consistent specification of mapping products was ordered on a menu basis according to different project needs.
All survey and mapping data was held centrally in an offline archive so it could be reused by the agency when other projects required such information. Set up originally for geotechnical surveys, it was quickly adopted for many engineering projects and other asset management tasks.
Blom UK – www.blom-uk.co.uk
