CHAPTER 6 THE TRAIN Couplers Federal Safety Appliance

CHAPTER 6 THE TRAIN

Couplers • Federal Safety Appliance Act of 1893 required standardization for safety reasons • Link-and-pin required going between cars • Swinging-knuckle design chosen for standard • Two types: E and F

Draft Gear • Used to cushion shock and strain on cars from movement • Friction in system absorbs energy • Most have a coupler travel of 5½ in. , but some cars (mainly boxcars) have 9½ in. of give.

Braking

Braking (continued) · Air Brakes · Dynamic Brakes · Independent Brakes

Braking System • Comprised of: -Brake pipe (connected by hoses between cars) -ABDX valve (triple valve) -Auxiliary reservoir -Emergency reservoir -Brake cylinder • Fail-Safe System

Braking System (continued) • Brake pipe and system charged with air to 70 -90 psi (110 psi on passenger trains) • Once charged, all brake valves in “release” position • Some leakage will occur such that each successive car will have less pressure • This is called “brake pipe gradient” and must be less than 15 psi for entire train

Applying Brakes • Engineer reduces pressure in brake line • Brakes apply on car next to locomotive • Reduction in air pressure travels through train, one car to the next • Can take several seconds for “signal” to reach end of train • Slack Action

EOT • End-of-Train (EOT) device monitors brake pressure at the end of the train and train movement and radios information to locomotive cab • If equipped with twoway communications, can be used to apply brakes from rear of train

Electronically Controlled Pneumatic (ECP)Brakes • Electronic signal activates brakes on each car nearly instantly (speed of light) • Flaw: Every car on the train must have wiring and electronic controls

• Train Dynamics • L/V Ratio • Train-Dynamics Analysis -Simulators -Cab Displays

Vehicle/Track Dynamics – Cab Displays

Positive Train Control

Positive Train Control

Positive Train Control