PGH Wong Engineering, Inc. and Transportation Decision Systems, Inc. jointly provide the transit industry with a integrated operations simulation capabilities. Our firms are unique in that we have a mix of experienced operations personnel as well as simulation and engineering capabilities. The program has been utilized and verified to within 5% of actual conditions on systems across the nation and has been utilized on systems such as New York City Transit, Bay Area Rapid Transit, Salt Lake City Light Rail, San Diego Light Rail, Sacramento Light Rail, and St. Louis MetroLink.

PGH Wong Engineering, Inc. and Transportation Decision Systems, Inc. developed the Traction Electrical Power Analysis Simulation Program (TEPAS), which is a set of integrated computer simulation tools specifically designed to analyze and evaluate the electrical performance of an electric rail system under a series of specified train power requirements. By using a detailed train performance simulation, TEPAS can examine power requirements under normal conditions and under a variety of abnormal and emergency circumstances.

TEPAS is suitable for analyzing and evaluating heavy and light rail transit systems and high speed electrified rail systems. It is capable of rapidly evaluating the performance of alternative power distribution system designs when supporting a variety of different train schedules. TEPAS is also useful for identifying limitations and problems in the design of existing power systems under present or proposed operations.

Program Modules
The state-of-the-art computer integrated TEPAS program provides for dynamic simulation of traction power and train control systems. The program is an integrated set of modules consisting of the following:

• Rail Transit Simulator (RTS) Module
  This module performs dynamic train operations simulation. Train control and signaling logic is fully modeled along with actual train schedules. The RTS module provides train location, speed, and tractive effort data to the TEPAS Analyzer.

• TEPAS Analyzer
  This module performs the dc load flow simulation for the electrical network. It provides complete electrical network solutions at one-half second intervals, or greater as selected, as trains circulate.

• TEPAS Selector (TS)
  TS is a data processing module which assists the user in selecting data of interest from the TEPAS Analyzer output.

• TEPAS Presenter
  TP is the output module which uses a set of Windows macros and customized user-friendly dialog boxes for preparing tabular and graphical output.

• TEPAS Launcher
  This is a Microsoft Windows-based interface permitting the operation of the above modules from an integrated user-friendly Windows interface. In addition, the TEPAS Launcher provides logic permitting the user to offset trains on one track from the other to determine worst case voltages at trains.

• TEPAS AC Analyzer(AC)
  This module, under testing, performs the ac load flow simulation for the electrical networks of ac electrification. It provides complete electrical network solutions at one-half second intervals, or greater as selected, as trains circulate.

Users of TEPAS
TEPAS has been used in numerous projects including the following:

• $3.7 Billion Bay Area Rapid Transit (BART) Extension to San Jose
• $16 Billion New York City Transit Second Avenue Subway Project