BMRCL begins soil testing on Sarjapur Road for proposed Namma Metro Red Line corridor

The soil testing work for the proposed Namma Metro Red Line being carried out on Sarjapur road in Bengaluru on Wednesday. | Photo Credit: SPECIAL ARRANGEMENT The Bangalore Metro Rail Corporation Limited (BMRCL) has begun geotechnical investigations along Sarjapur Road for the proposed 37.8-km Bengaluru Metro Phase 3A corridor, also known as the Red Line, which is planned to connect Sarjapur in southeast Bengaluru with Hebbal in the north.The investigation will assess the characteristics of the soil and underlying rock formations along the proposed alignment before construction work begins. The findings will help engineers evaluate ground conditions and determine the technical requirements for building the elevated and underground sections of the metro corridor, according to the BMRCL officials.Namma Metro Phase 3A (Red Line): Key DetailsRoute: Hebbal to Sarjapur RoadRoute Length: 37.8 kmRoute Composition: 23 km elevated and 14 km undergroundMajor Areas Covered: Hebbal, Central Business District, Koramangala, SarjapurLatest Estimated Cost: ₹25,999 croreSpeaking to The Hindu, a senior BMRCL official said, “The study will provide essential information about soil stability, geological formations and other ground conditions along the route. These findings will guide decisions on foundation depth, structural design and the construction requirements for metro pillars, helping ensure the safety and stability of the infrastructure.”Meanwhile, the proposed project awaits approval from the Union government, the officials confirmed. The State government has submitted the Detailed Project Report (DPR) for the corridor, but the Centre has not specified a timeline for granting its approval.As previously reported by The Hindu, the Ministry of Housing and Urban Affairs (MoHUA) informed Parliament in August that the project was still undergoing detailed scrutiny. Its approval would depend on the outcome of the feasibility assessment and the availability of financial resources. The clarification was provided in a written reply to a question raised by Ajay Maken in the Rajya Sabha. The ministry stated that metro rail projects require substantial capital investment and must undergo a comprehensive assessment in accordance with the Metro Rail Policy, 2017, before receiving approval. Consequently, it said that no specific timeline could be provided for sanctioning the proposed corridor. The project has been under review for an extended period, with discussions between the State and Union governments focusing on its estimated cost, particularly the expenditure associated with underground construction.In response to concerns raised during the appraisal process, the BMRCL undertook a cost-reduction exercise involving changes to underground station designs, adjustments to the alignment and modifications to station locations. The corporation also engaged an engineering consultancy to examine the project estimates and identify opportunities to reduce expenditure without compromising operational requirements.According to the BMRCL officials, the revisions included reducing the lengths of underground stations, comparing construction costs with those of similar metro projects and modifying various engineering specifications. These measures substantially lowered the estimated project cost.Once completed, the Red Line is expected to improve connectivity between Hebbal and Sarjapur Road, linking important residential and commercial areas, including Koramangala and Bengaluru’s Central Business District, as well as the city’s southeastern information technology corridor. Published - October 15, 2026 06:00 am IST