definition of a key train

A "Key Train" is any train with:
* one tank car load of poison or toxic inhalation hazard (PIH or TIH) (Hazard Zone A, B, C, D) or anhydrous ammonia, or;
* 20 car loads or intermodal portable tank loads of a combination of PIH or TIH (Hazard Zone A, B, C, D), anhydrous ammonia, flammable gas, Class 1.1 or 1.2 explosives, and environmentally sensitive chemicals, or;
* one or more car loads of Spent Nuclear Fuel (SNF), High Level Radioactive Waste (HLRW).