﻿GET_GEVOMechL2_07_01_01_83 - ANIMATION Screen
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You have reached the end of this module!

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In this module, you learned to:

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State the purpose and location of the steerable trucks.

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The three-axle G1 model steerable truck is a three-motor, three-axle, high-adhesion, steerable type truck designed to carry one-half the weight of the locomotive.

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The entire locomotive is supported by two steerable trucks, commonly called the front truck and the rear truck.

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These truck assemblies are located directly underneath the locomotive platform.

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Each steerable truck, designed to carry one-half of the weight of the locomotive, has three axles that are individually powered by traction motors.

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The steerable trucks distribute the locomotive weight equally over the axles, and transfer the tractive effort or pulling force, and braking effort or stopping force, from the locomotive to the rails.

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Describe the major components of a steerable truck.

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The truck frame is the backbone and foundation for the steerable truck assembly.

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It is a C-shaped steel casting that provides the mounting for all of the steerable truck’s components.

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The wheels transfer the torque generated by the traction motor and apply it to the rails.

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The wheels are designed to keep the locomotive on the rails.

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The lateral liners, two per axle bearing housing, provide a wear surface between the axle bearing housing and the truck frame.

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Working together, the brake cylinders, brake rigging, and brake shoes apply stopping force to the wheels.

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The traction motor nose suspension, also referred to as the dog bone or suspension link, provides support for the traction motor between the motor and the truck frame.

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The rubber side bearers, also referred to as loadbearers, consist of alternate layers of steel laminations and rubber, which are bonded together.

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The side bearers, mounted on the topside of the truck, transmit the locomotive weight to the trucks, while permitting controlled lateral motion of the trucks relative to the locomotive platform.

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The rubber traction pads, consisting of alternate layers of steel and rubber that are bonded together, function to transmit the tractive effort from the truck to the locomotive, while permitting controlled lateral motion of the trucks relative to the locomotive platform.

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The traction pads also absorb the shock between the center pin bearing assembly and the truck frame during acceleration and braking.

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A center pin, located on the underside of the locomotive platform, fits into a center pin bearing assembly mounted in the truck frame.

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The center pin is welded to the underside of the platform and mates with the truck by way of the center block.

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The bearing assembly and the center pin allow the truck to pivot with respect to the locomotive platform and transmit the tractive force from the truck to the locomotive platform.

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The lateral and yaw dampers are used to dampen unwanted movement and vibrations between the truck and the locomotive platform.

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There are two lateral and two yaw dampers per truck.

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There are four primary or vertical dampers on a steerable truck.

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The primary dampers are used to dampen unwanted movement and vibrations between the wheel axle assembly and the truck.

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The coil springs transfer the weight of the locomotive to the wheel and axle assembly, dampen vertical forces, and improve ride quality.

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There are twelve coil-compression springs, one spring located on each side of each journal bearing housing.

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Safety hooks ensure that the truck does not become separated from the locomotive.

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They are located on both sides of each truck frame.

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The steering assembly is a series of mechanical linkages that cause the axles to adjust to the curvature of the track.

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There are several components that make up the steering assembly.

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The equalizer bar, also referred to as a “Marty” bar, and equalizer arms are attached to the open end of the bell cranks.

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The equalizer arms are heat-shrink fitted to the top of the bell cranks.

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The equalizer bar is attached to the equalizer arms by a close tolerance hardened pin with hardened bushings.

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The bell crank is a vertically oriented shaft that rotates within the truck frame through two rubber laminated bearings.

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The bell crank permits the traction motor combination yaw rotation to be transmitted to the externally mounted reaction arms.

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G1 steerable trucks have an equalizer bar damper attached between the steering arrangement and the truck frame.

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The damper reduces vibration induced by the steerable arrangement in the lateral direction.

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Reaction arms and wing plate assembly arrangement helps to ensure that the two axles are acting in equal and opposite direction.

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As the end axles rotate in equal and opposite direction in yaw, the reaction arms rotate relatively.

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The wing plate assembly will displace inward or outward relative to the truck frame depending upon the direction of steering.

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The traction link and the center link transmit and react to the tractive, braking, and steering forces from the wheel set journal box to the truck frame.

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Links are connected to the axle bearing housing, also known as the journal box.

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The other ends are attached to the truck frame through a smaller casting called a traction cap.
