The much-awaited Yellow Line of Bengaluru’s Namma Metro, which was earlier expected to be operational by mid-2024, has been hit by yet another delay. According to a Deccan Herald report, the 19.15-km line connecting RV Road with Bommasandra is now unlikely to open before the end of July — or even August — owing to critical issues in the train signalling system.

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Why the delay?
Officials from Bangalore Metro Rail Corporation Limited (BMRCL) told the publication that the delay is due to pending Independent Safety Assessment (ISA) approvals for signalling systems. The certification is held up due to glitches found in the software datasets during the review process by Siemens India Ltd, the Yellow Line’s signalling contractor.
“Train movements are controlled entirely by software. Even a minor error defaults the system to a safe mode,” a senior BMRCL official is quoted as a saying by the publication. The official added that while BMRCL has completed all statutory tests, the ISA nod is crucial before the Commissioner of Metro Railway Safety (CMRS) can inspect the line.
“Unless all tests are cleared for safety, Siemens cannot approach the independent assessor,” the official said, noting that the delay is now out of BMRCL’s hands. Siemens has reportedly assured that the corrected datasets will be ready by the end of June.
{{/usCountry}}“Unless all tests are cleared for safety, Siemens cannot approach the independent assessor,” the official said, noting that the delay is now out of BMRCL’s hands. Siemens has reportedly assured that the corrected datasets will be ready by the end of June.
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The delay has also reportedly been compounded by issues with train availability. Titagarh Rail Systems Limited (TRSL), which is supplying the rolling stock for the Yellow Line, is behind schedule. However, production is now on track, said the report further. Of the six trains required to start operations, three have arrived so far — all sourced from China
The repeated delays come despite Karnataka Deputy Chief Minister D K Shivakumar setting a May 2025 deadline for Yellow Line operations. However, with the line already missing several earlier timelines, the project is now under increased scrutiny.