Freight Wagon

Overview

The Freight Wagon is a covered hopper railcar for bulk dry goods. A welded underframe and a sloped hopper body ride on two three-piece bogies, joined to the rest of the train by AAR knuckle couplers and braked by an AAR pneumatic system. Material loads through roof hatches and discharges by gravity through gates at the base of each bay. End buffers and a set of access fittings round out the car.

Underframe

The Underframe is the structural spine. A Center Sill runs the length of the car between two Side Sill sills, with Headstock (End Sill) end sills and Cross Bearer cross bearers tying the structure together. At each end a Draft Gear Pocket houses the coupler and draft gear, transmitting buff and draft loads from coupling and train action into the frame. A Fastener Set secures the assembled members.

Hopper body

The Covered Hopper Body holds the cargo. Three sloped Hopper Bay bays funnel the load downward between Side Wall Panel panels and End Wall Panel ends, capped by a Roof Panel with four Loading Hatch loading hatches for top filling. At the bottom of each bay a Discharge Gate releases the load: a Gate Slide Plate plate driven by a Gate Rack & Pinion Mechanism rack and pinion opens to let gravity empty the bay, sealed against leakage by Oil Seal seals and a Fastener Set.

Three-piece bogies

Each Three-Piece Bogie is a standard three-piece freight truck: two cast Cast Side Frame side frames spanned by a cast Cast Bolster. Two Wheelset wheelsets carry the truck, each a Axle pressed with two Monobloc Wheel monobloc wheels, riding on Ball Bearing roller journals seated in Bearing Adapter adapters. Suspension comes from a Suspension Spring Group nest of Coil Spring springs on Spring Seat seats, damped by Friction Wedge wedges that load against the side frames to control ride. Each truck also carries Brake Beam beams with a Brake Beam Strut strut and two Brake Shoe shoes that clamp the wheels.

Couplers

The car connects through two AAR Knuckle Coupler AAR Type-E knuckle couplers. A Coupler Body body carries the rotating Coupler Knuckle that locks into the mating car, backed by a Coupler Yoke and a Draft Gear friction unit in the draft pocket that cushions the shock of coupling and train slack.

Air brake system

Braking is handled by the AAR Air Brake System. A Air Brake Control Valve, with its Control Valve Body, Valve Diaphragm diaphragms, and O-Ring Set seals, watches pressure in the Brake Pipe train line and, on a pressure drop, ports air from the Air Reservoir into the Brake Cylinder. The cylinder, built from a Cylinder Body and Cylinder Piston with Oil Seal and O-Ring Set seals, drives the Brake Rigging of Pull Rod rods and Brake Lever levers to apply the shoes, with a Slack Adjuster taking up shoe wear. For parking, a Hand Brake with a Hand Brake Wheel, Hand Brake Chain, and Hand Brake Gear Set applies the rigging manually.

Buffers and access

End Buffer / Bump Stop bump stops, each a Buffer Head backed by a Coil Spring in a Buffer Housing, cushion end contact during shunting. Crew access comes from the Access Fittings fittings: Grab Iron grab irons for handholds, Ladder ladders climbing to the roof, and a Roof Walkway roof walkway reaching the Loading Hatch loading hatches, all secured by a Fastener Set. These fittings let crews load through the roof and operate the Hand Brake safely from the car's end platform, which is why their placement is governed by railroad safety appliance standards rather than left to the builder.