I have been following the investigation into this tragic accident, looks like surveying and mapping tools are well represented as part of that investigation.
"The TSB also announced that it continues to make progress in its investigation. The board has: downloaded key information from the locomotive event recorder and braking unit; inspected the tracks, conducted a site survey, and completed photogrammetry and videography to determine track grade and position; conducted mechanical inspections and photographed 22 tank cars to document accident damage; taken samples of products inside selected tank cars to determine their exact properties; and interviewed the locomotive engineer, MMA employees and several first responders, such as firefighters.
The TSB currently is conducting three-dimensional (3D) laser imaging of the accident scene with help from the National Transportation Safety Board. The imaging will record 3D data of the scene and different pieces of the wreckage."
SHG
I did a few site surveys in the 1990's for the NTSB involving railroad wrecks that had fatalities. Very interesting stuff. Not for the weak though, as the scene was quite fresh and we needed to document the locations of certain things. I remember one was where a railroad worker got coupled between two cars. The exact location had to be pinpointed. I'll spare the details...