﻿GET_GEVOMechL2_07_01_01_84 - ANIMATION Screen
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Describe the basic operation of a steerable truck.

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The 3-axled steerable truck has a series of steering linkages that force the first and third axles in equal and opposite directions, while the second axle moves laterally, towards the outside of the curve.

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Each set of wheels is powered by its own traction motor.

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The truck frame is supported by coil springs with primary dampers, which dampen vertical spring oscillations.

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A center pin and center pin bearing assembly transmit the tractive force from the truck to the locomotive platform.

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The side bearers support the vertical load and provide controlled lateral motion between the locomotive and the truck.

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The journal bearing housings transfer vertical loads from the frame to the axles and wheels.

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The primary, lateral, and yaw dampers reduce unwanted movement.

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The primary dampers reduce the motion between the truck frame and the axle.

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The lateral dampers reduce unwanted lateral motion of the truck as the locomotive moves along the track.

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The yaw dampers prevent the truck from “hunting the rail” as the locomotive moves along a straight track.

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Finally, brake cylinders, brake rigging, and brake shoes provide braking at each of the six truck wheels.

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Describe how to perform running maintenance inspections related to the truck and its major components.

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Wheels

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Periodically inspect the wheels for damage or excessive wear, in accordance with Federal Railroad Administration (FRA) Regulations.

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To measure wheel diameter, flange thickness, and flange height, use a wheel gauge.

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The wheel diameter is measured by reading the scale on the long arm of the gauge in relation to the top of the witness mark on the wheel using a conversion chart.

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The flange thickness is measured by reading the scale on the pivot arm in relation to the 0 mark on the stationary arm.

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The mark on the pivot is used to determine the thickness.

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The flange height is measured by reading the scale on the pivot arm in relation to the marks on the bend of the gauge.

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Lateral Liners

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If the lateral liner clearances exceed the maximum worn limits, replace them as follows:

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1. At the pin retainer assembly, remove the bolts, the hardened washers, and the journal box retainer pin from the truck frame, then save the hardware for re-assembly.

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2. Remove both journal box retainer pins.

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3. The liners should fall out but, if not, remove them with an appropriate tool.

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4. Position the new liners in place and return the correct tee bolts.

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5. Re-install the pin retainer assembly, with the raised portion toward the truck frame, and fasten using the previously saved hardware.

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6. Torque the retainer assembly bolts.

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Brake Shoes and Rigging

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The brake shoes are a high-wear item and need to be inspected on a regular schedule.

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Inspect adjustment and condition of the brake rigging components as follows and make adjustments and repairs as required:

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Periodically check all brake shoes for wear.

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Ensure that the brake shoes are not binding against the wheel thread surface or flange.

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Verify that the brake hangers are not causing misalignment of the brake shoe.

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Inspect brake linkage for missing, broken, or loose parts.

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Also, inspect for badly worn pins, bushings, or wear plates.

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Check the brake rigging wear plates on the hangers and the truck frame pads.

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Check the clearance between brake shoes and wheels.

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Check the brake cylinder piston-rod travel that is required to engage the brake.