TPerf© is a highly accurate train performance simulator that determines the speed, time, distance and energy consumption of a train running over a track profile. The model includes the effects of grades, curves, train resistance, speed restrictions, propulsion characteristics and brake characteristics.
The model achieves its accuracy by employing numerical integration using a fixed time step. This enables accurate models of the propulsion and braking systems that can include non-linear relationships between speed and tractive effort. This contrasts with many models that employ a hybrid of closed form calculations and numerical integration. These models generally cannot simulate the effect of variations in braking rate versus speed such as high speed brake taper. They also succumb to computational inaccuracies as the simulation shifts between numerical integration and closed form calculations. The hybrid models are relics of batch processing computer programming and do not exploit the power of the modern desktop computer.
TPerf© is implemented in Visual Basic 6 and runs on the Windows operating system. Data entry for track plan and profile is particularly efficient. Built in spreadsheets allow separate entry of station locations, speed restrictions, elevations and curve radii versus track location. Similar spreadsheet type entry is used for vehicle characteristics. Data can be changed rapidly and the effects on performance can be quickly determined.