An investigation committee has concluded that both bearing pads that detached from a metro rail pillar in the capital’s Farmgate area were defective, while finding no evidence of sabotage in the incident that claimed a pedestrian’s life.
The findings were shared on Thursday during a briefing at conference room of Road Transport and Highways Division at the Secretariat, in presence of Adviser for Power, Energy and Mineral Resources, Road Transport and Bridges and Railways Muhammad Fouzul Kabir Khan.
According to the committee, two out of eight to ten tested parameters of the dislodged bearing pads did not meet expected standards.
However, the committee cautioned that this alone does not allow a definitive conclusion on whether all bearing pads used in the metro rail system are either good or faulty.
The adviser said that on October 26 last year, a bearing pad detached from a metro rail pillar in Farmgate, killing a pedestrian named Abul Kalam, a resident of Shariatpur.
Following the incident, a five-member investigation committee was formed on the same day, headed by Bridges Division Secretary Mohammad Abdur Rouf.
The committee included BUET Mechanical Engineering Professor Dr ABM Toufik Hasan, MIST Civil Engineering Associate Professor Lt Col Md Zahidul Islam and Dhaka Mass Transit Company Limited (DMTCL) Line-5 Project Director Brigadier General (retd) Mohammad Abdul Wahab.
Deputy Secretary Asfiya Sultana served as member secretary. Later, the Chief Engineer of Local Government Engineering Department was added to the committee, along with two co-opted experts from BUET; Prof Dr Khan Mahmud Amanat and Prof Dr Rakib Ahsan.
A CID forensic representative, Mohammad Touhidul Islam, was included to investigate any possibility of sabotage.
The committee began work immediately, inspecting the accident site and interviewing eyewitnesses, train drivers, operators, metro rail officials, as well as the bearing pad manufacturer, contractors and design consultants.
Design documents and relevant data were thoroughly reviewed. Laboratory tests on the detached bearing pads, vibration measurements during train operations and inspections of various metro rail structural components were also conducted.
After holding 10 meetings, the committee finalized its report.
The adviser said preliminary findings indicated that the hardness, compression set and neoprene content of the displaced bearing pads did not fully comply with standard specifications.
Further tests at foreign laboratories have been recommended to confirm the results. The pads were also installed at a slight slope of 0.8 percent, which may have contributed to their displacement.
The committee observed that both ends of Farmgate station are located on curved alignments, but no transition curve was used between the straight and curved sections of the viaduct.
It noted potential design flaws, as curved alignment sections were designed based on straight alignment modelling without separate analysis.
Vibration measurements showed significantly higher vibrations at piers 430 and 433; where the bearing pads were displaced, compared to other piers. These excessive lateral forces and vibrations are believed to be linked to the bearing pad failure.
The investigation further found that while a neoprene rubber mass-spring damper system was used under the tracks at curved sections and near stations, rigid tracks were installed at the accident site.
The committee believes that installing mass-spring damper systems at those locations could have reduced vibrations. However, it reaffirmed that no evidence of sabotage was found.
The committee has made five key recommendations:
1. Urgent installation of appropriate technical measures to prevent bearing pads from shifting at curved alignment locations, which DMTCL has already begun implementing;
2. A detailed structural and track design review by an independent third-party consultant to conclusively determine the causes of bearing pad displacement;
3. A third-party safety audit of the entire metro rail project design;
4. Rapid installation of an effective structural health monitoring system for close observation; and
5. Strengthening institutional capacity of the metro rail authority and ensuring technology transfer from foreign consultants to local experts.
It is worth noting that a bearing pad first fell from a metro rail pillar in Farmgate on September 18, 2024, disrupting train operations for 11 hours but causing no casualties.
A second incident occurred on October 26, when an 80kg bearing pad fell from a pillar at around 12:30 PM, killing a young man and again halting metro rail services.
The fatal incident prompted the government to form the investigation committee.
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