The Ministry of Railways has voiced its opposition to the use of a particular fastening system in the tracks that will be constructed as part of the 140-km Phase 3 expansion of Delhi Metro.

The type of fastening system that involves fixes rails to the steel plates, rubber pads and clips of the concrete pads was earlier used in the Delhi Airport Metro Express line. The DMRC was planning to use RHEDA system for ballastless track with Vossloh 300 fastening system; however the Indian Railways has expressed its opposition to the plans.

The ministry is opposing plans because major damages appeared in the airport line a few months after its construction and it put passengers in danger. Reliance Infrastructure, which is the concessionaire for the Airport Metro Express Line of the Delhi metro in the national capital, has accused the Delhi Metro Rail Corporation (DMRC) of forcing it to use faulty chips in the underground section.

DMRC has used track systems from Patil Vossloh Rail System Pvt Ltd in its phase 1 and 2. The DMRC has also written several letters urging the Railway Ministry to approve the use of RHEDA track form with Vossloh 300 fastening system for phase 3. However, the ministry is not ready to approve the move because of the defects in the airport line.