49 CFR §674.33

1. (a)An RTA must notify FTA and the SSOA within two hours of any safety event occurring on a rail fixed guideway public transportation system that results in one or more of the following:
   1. (1)Fatality
   2. (2)Two or more injuries
   3. (3)Derailment
   4. (4)Collision resulting in one or more injuries
   5. (5)Collision between two rail transit vehicles
   6. (6)Collision resulting in disabling damage to a rail transit vehicle
   7. (7)Evacuation for life safety reasons
   8. (8)Unintended train movement.
2. (b)The two-hour notification requirement excludes criminal actions that result in fatalities or injuries, such as homicides and assaults.