The Center for Transportation Safety, Security, and Risk (CTSSR) at Rutgers University is using the Northeast Corridor as a testbed to improve the resilience of passenger rail corridors. This article describes three complementary simulation models in development at CTSSR which will offer insights into events that can cause cascading impacts in rail and connected transportation systems, explore the consequences of those events, and identify investments that could increase system resilience after accidents and attacks. The models will also be valuable for education and training and for adaptation to other rail corridors.