National Research Council of Canada. NRC Centre for Surface Transportation Technology
The track geometry interaction map (TGIM) is proposed as an effective way to evaluate the impact of multiple track geometry parameters on rail safety. Multi-body dynamics software has been used to simulate vehicle performance over tracks containing a large number of randomly generated lateral and vertical track geometry combinations. A TGIM-based safety threshold is generated that appears to offer both economic and safety advantages over the current Federal Railroad Administration track safety standards.
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit223, no. 2: 111–119.