PRECISE RAIL TRACK SURVEYING

In this article, the authors describe how the Swiss Trolley, a multi- sensor measurement system, makes us of real-time kinematic (RTK) Global Positioning System (GPS) to survey sections of railroad track in the U.K. They describe the system design, how the sensors are used, and the 3-step cascading data processing which involves blunder detection, synchronization, and filter and smoother. A survey example in which the performance of the Swiss Trolley was evaluated by comparing a forward and a backward run on a 250-meter section of track is also described.