Our experience ranges from new build route surveys, to capturing the existing rail infrastructure prior to upgrade works, repairs and improvements.
In Africa we were involved in an aerial lidar survey mapping more than 800km of proposed new rail route options, that would enable the transport of iron ore from Guinea, through Liberia to the coast. This involved nearly 1000km of spirit levelling on the ground.
The UK’s rail network has been surveyed from the air using helicopter baser lidar equipment. Merrett Survey Limited’s task was to assist in checking the accuracy of the aerial survey company’s work. Merretts are experts in the independent measuring of lidar accuracy in both the horizontal and vertical planes.
Surveys of bridge sites and short sections of line can be completed for clearance studies or modification work.
Overlapping with the heritage aspect of our work, we recorded the last timber rail bridge in UK before it’s demolition to be replaced and widened and built in more modern materials. This was an interesting project involving us in providing laser scanning and 3D modelling of the structure itself, 2D topographical survey of the approach road and rails, bathymetric side scan sonar work to determine the position of the underwater timber piles. Plus an aerial lidar survey of the surroundings and inter-tidal sand banks to study future erosion / deposition patterns in the tidal river estuary that the bridge crosses.
Underground and above ground surveying
Survey of tram projects as well as rail