Early dangers
Workers coupled cars by hand, rode the tops of moving freight cars, worked around unguarded machinery, and operated without many modern safety systems.
Automatic couplers and air brakes
Federal safety laws helped accelerate adoption of automatic couplers and power brakes, reducing the need for workers to go between moving cars and improving train control.
Signals and train control
Block signals, centralized traffic control, automatic train stop systems, and modern Positive Train Control added layers of protection against certain kinds of collisions and overspeed events.
Safety remains active work
Railroad safety still depends on maintenance, inspection, training, operating discipline, technology, public awareness, and learning from accidents.