Gangway — The Unsung Critical Link Between Metro Cars

The gangway, the seemingly inconspicuous connection between metro carriages, is in fact a sophisticated engineered component.

A Type B metro train requires 5 gangways. It serves to connect carriages, accommodate train movements and protect passenger safety. As one of the few flexible, movable assemblies on the train, it flexes as the train negotiates curves. During operation, it provides sound insulation, thermal insulation, dust protection and rainproof performance.

Let’s take an in-depth look. This article elaborates on its structure, installation, maintenance intervals and common faults.

Gangway Composition

It consists of the body frame, bellows, ceiling panel, side guard panels, tread plate and footboard.

Technical Parameters

• Clear width: 1300 mm

• Clear height: 1900 mm

• End-to-end distance: 520 mm

Gangway Installation Procedure

Before installation, inspect the mounting holes on the car end wall to confirm compliant interfaces.

Installation sequence: Body frame installation → Bellows installation → Footboard installation → Gangway plate connecting rod installation → Gangway plate installation → Ceiling panel installation → Side guard panel installation

1. Body frame：Fasten bolts at the four corners first, then tighten the remaining bolts. Do not fully torque the bolts at this stage; final tightening with a torque wrench shall be performed after all fasteners are fitted.

2. Bellows：Open all latches around the body frame. Lift the bellows with a lifting appliance, align it with the sealing strips of the body frame, then close all latches on the frame.

   
   

   

3. Footboard：Align the holes on the footboard with those on the car body, and tighten fasteners using a dedicated torque wrench.

   
   

   

4. Gangway plate connecting rod：The connecting rod is fixed to the footboard. Insert the pin and fit the cotter pin to secure it.

   
   

   

5. Gangway plate：The gangway plate is not bolted in place; it is secured by tension latches on both sides. Fit the gangway plate assembly, align holes on the reverse side of the plate with the locating studs on the connecting rod, then release the latches. Spring tension locks the gangway plate into position.

The opening and closing function of the gangway plate is critical. It will be opened for inspection and cleaning during periodic system overhaul.

6. Ceiling panel：Two operators are required. One holds the panel and aligns it with the threaded holes on the car body, while the other tightens bolts using a calibrated torque wrench.

   
   

   

7. Side guard panels：Before fitting side guard panels, unlock the mounting brackets with quarter-turn locks and leave them unlocked. Slide the side guard panels into place horizontally. An audible “click” confirms correct seating.

The gangway installation is now complete. For disassembly, reverse the installation sequence: Side guard panel removal → Ceiling panel removal → Gangway plate removal → Gangway plate connecting rod removal → Footboard removal → Bellows removal

This simple-looking joint structure embodies precision rail transit engineering. The locking feedback of quarter-turn locks, tolerance matching between guard panels, sealing and wear resistance of bellows, and long-term reliability of gangway plates and footboards under vibration and repeated disassembly all require design validation, type testing and on-site process confirmation. Installation and disassembly on site must strictly follow technical procedures.

Gangway Maintenance Interval & Inspection Items for System Overhaul

1. Check that connecting rods of side guard panels and base plates have no severe bending or deformation; the linkage mechanism shall move freely without jamming or interference with adjacent components.

2. Inspect footboard welds for cold joints, incomplete fusion or weld detachment. Flip the footboard and verify smooth rotation of hinges. Confirm gangway plate connecting rods are properly fitted and free of bending/deformation; adjust if necessary. Check locating pins of gangway plates for integrity, no deformation or loss.

3. Inspect wear strips on gangway plates, ceiling panels and side guard panels for wear.

Wear strip criterion: Replace if the distance from the bottom of the gangway plate wear strip to the rivet is less than 0.2 mm.

4. Verify no abnormal noise during gangway plate travel; lubricate sliding surfaces with lithium-based grease.

5. Check metal frame supports of the gangway for fractures.

6. Inspect linkage mechanisms for bending, deformation and jamming; lubricate vertical sliding surfaces of side guard panels.

Common Faults & Solutions

How to test gangway airtightness?

Airtightness can be tested via pressure differential method or smoke test for joint air leakage; sound level meters are used to measure sound insulation performance.

What to do if small holes appear on aged bellows?

Repair by patching with special repair adhesive. Cut a patch larger than the damaged area. Before application: grind the area around the hole, round the edges to form a chamfer, wipe thoroughly with alcohol, then carry out patching.

There are hundreds of different gangway mounting interfaces for metro vehicles across China, with varying parts and dimensions among different rolling stock. It is hoped that gangway interfaces will be further standardized and maintenance procedures more standardized in the future, making this “unremarkable joint” safer and more reliable.

(Reference: Leading manufacturers in the industry)

A final reminder: Although gangways connect carriages, accommodate curve negotiation and provide sound insulation and dust protection, relative movement and sway occur here during train cornering, acceleration and deceleration, posing a fall risk to passengers. Do not stay for long periods. Hold handrails when passing through, avoid leaning against guard panels, and never put hands into bellows gaps. Parents shall supervise children closely.

Source: Rail Transit Life. Please contact us for copyright removal if needed.