Assembly Method for Type 17 Coupler (AAR F Coupler Standard)

Assembly Method for Type 17 Coupler (AAR F Coupler Standard)

1. Overview

There are two assembly processes for the Type 17 Coupler and Draft Gear assembly: one using a hydraulic lifting trolley, and the other using a dedicated Type 17 draft gear loader/unloader.

2. Assembly via Hydraulic Lifting Trolley

Prior to assembly, the draft buffer must be pre-compressed. MT-2 buffers fitted on newly manufactured wagons are pre-compressed at factory; MT-2 buffers reused during overhaul require re-pre-compression.The following procedure takes the C70 general open-top wagon as the reference model:

2.1 Assemble the buffer, Type 17 coupler follower and Type 17 yoke as a subassembly.

2.2 Lift the pre-assembled buffer-follower-yoke unit into the draft sill using the hydraulic lifting trolley.

2.3 Fit the yoke bolster assembly and safety bolster (omitted on certain wagon types).Raise the trolley to push the buffer-yoke subassembly fully into the draft sill, align the bolt holes of the yoke bolster and safety bolster, insert M22×80 bolts top-down, fit matching washers and BY-B lock nuts.

2.4 Install left/right stop blocks, support springs and coupler support seats sequentially into the coupler striker.

2.5 Insert the Type 17 coupler into the yoke through the front opening of the striker.

2.6 Align the Type 17 coupler tail pin with the pin holes of the yoke and insert the pin; mount spacer blocks and tail pin bolster assembly. Insert M24×90 bolts top-down, then fit matching washers and BY-B lock nuts in sequence.

2.7 Press the coupler downward with a pry bar to lower the coupler support seat, engage the stop blocks with the lugs of the coupler support seat. Align holes between stop blocks and striker, insert M20×90 bolts top-down, fit matching washers and BY-B lock nuts sequentially.

2.8 Fit coupler lift lever and lift lever bracket: thread the lift lever through the bracket, insert one end of the lift lever into the rotary shaft of the Type 17 coupler bottom lock pin. Align holes of the lift lever bracket and bracket hanger, install M16×50 bolts from inside out, fit Φ16 spring washers and M16 nuts and fully torque them; perform tack welds on bolt-nut joints.

2.9 Install tension springs, anti-jump pins and brake hose hang chains.

3. Assembly via Dedicated Draft Gear Loader/Unloader

Two pre-installation options for the buffer are available: either pre-compress the buffer in advance, or assemble the buffer, follower and yoke first then install shims between the yoke and follower before fitting the subassembly (refer to schematic drawing).The following procedure takes the C70 general open-top wagon as the reference model:

3.1 Place pre-compressed MT-2 buffer, follower and yoke subassembly onto the loader/unloader.

3.2 Align the MT-2 buffer-follower-yoke unit on the loader/unloader with front/rear follower seats and center sill. Lift the loader to push the front follower and buffer into the gap between front and rear follower seats, then mount safety bolster with matching bolts, nuts and washers.

3.3 Exit the forklift, and install the coupler yoke bolster together with corresponding bolts, nuts and washers.

3.4 Install left/right stop blocks, support springs and coupler support seats sequentially into the coupler striker.

3.5 Align the tail of the coupler secured on the loader/unloader with the center of the striker, operate the loader to insert the coupler tail into the front cavity of the yoke.

3.6 Insert the coupler tail pin after hole alignment, then fit the tail pin bolster.

3.7 Press the coupler downward with a pry bar to lower the coupler support seat, lock the stop blocks onto the coupler support seat, then install corresponding bolts, nuts and washers.

3.8 Mount coupler lift lever and lift lever bracket.

3.9 Torque all fitted nuts with an air impact wrench as specified; insert cotter pins and spread both legs to an angle between 60° and 70°. For all assembled bolts, the thread shall extend at least one full thread pitch beyond the nut face, and the exposed thread length shall not exceed the thickness of one nut.

3.10 Install tension springs, anti-jump pins and brake hose hang chains.

4. Video of assembly: