Surveying
systems are combined and backed up with direct gauging measurements for structure clearances such as for platforms, signals, OHLE, tunnels and bridges. Consistency of data is paramount and this is why TSA member companies feed into and follow the Network Rail Survey Standards. TSA member companies have not only kept up with the latest standards and specifications in the rail industry but also the very latest surveying technology which is constantly evolving.
This has seen the development of track
measuring devices (TMD’s) to improve the repeatability of rail measurements for alignment analysis. These are very often operated in absolute 3D coordinate systems using rail grid geodetic software to ensure engineering scale factor 1 over complete ELR’s. These bespoke rail grids provide consistency and allow survey work and design to be carried out across different parts of the network at the same time to meet NR deadlines; they can be used again into the future ‘working from the whole to the part’ underlying a key fundamental survey principle, necessary for quality survey.
The survey monitoring of railway track
while under track crossings and nearby construction works such as piling are taking place has traditionally been completed manually. However recent advances in technology have enabled construction and monitoring periods over months to benefit from automated 24 hour monitoring systems with the data automatically emailed off site. A high accuracy TS30 0.5” total station with meteorological readings for automated temperature and pressure adjustments takes observations to prisms fixed to the web of the rail - continually. Reports on vertical rail movement, cant and twist are automatically generated for survey team and client assessment locally and remotely. The Leica Geo-Moss system provides for this and can be even powered
by solar panels so it’s environmentally friendly as well as safer than manual on track assessment and also provides cost savings. Terrestrial laser scanning has enabled the rapid data capture of huge 3D point cloud data sets where access to the rail environment is limited especially with
the increased Rail Operator services. Laser scanning has also been developed to affix to the TMD systems and provide even larger data collection through kinematic laser scanning. This type of technology allowed Severn Partnership to survey the Severn Tunnel, 7 km long in three nightshifts, one of which included a walk through with the Amberg GRP5000 kinematic laser scanning system. A rigorous survey spigot control network was installed in the tunnel with GPS control baselines at either end. Point clouds are an ideal data set for
3D modelling. Many TSA companies have 3D Modelling capability providing the rail industry with fully rendered models for design and visualisations to help throughout all stages of planning particularly useful within GRIP stages 2-6. The 3D models are used for public
consultation meetings, can be published on websites, used for high and low accuracy design, visualisations for signal sighting and interaction outside the rail industry such as at level crossings and railway stations. In the future these 3D models will be increasingly used by the rail industry in the government’s drive to Building Information Model (BIM), which also applies to infrastructure. Advances in BIM in the rail industry will be key to the network’s development and are realised with technical
March 2013 Page 75
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116