A system for simulating a railroad track. The system comprises one or more modular track simulation units that are smaller than conventional track simulators and are easy to use with and be connected to a device being tested (e.g., grade crossing predictor). Each track simulation unit may have one of a plurality of impedances associated with a corresponding railroad track length. The units are combinable such that the system can simulate multiple, different track lengths. Each unit has a plurality of test points that can be connected to the device under test and/or used to alter conditions of the simulated track.