Until recently, while capabilities existed to predict each of these resources individually, Union Pacific Railroad had no means of knowing the interaction of these resources to determine tradeoffs and insuring that a transportation plan based on projected market forecasts is achievable and cost effective. There are five critical resources associated with operating a railroad - crews, locomotives, mainline track, terminals, and rail cars. The Network Simulation Model simulates all of these resources except rail cars. In addition to current and projected information on these resources the simulation requires a train schedule, network topology, business policies that affect the use of resources and the movement of trains. The simulation engine creates trains from the schedule database.
Trains compete for resources such as crews, locomotives, and mainline.
The movement of trains on mainline is animated. The model writes simulation events to output files. The simulation is run for a specified number of weeks. A two-week simulation of the entire railroad network can be simulated within 20 minutes. The following are the critical outputs used to measure the achievability of the transportation plan.