Urban Transport News reports that two Chennai Metro Line 4 tenders have been floated.

https://www.urbantransportnews.com/news/tenders-invited-for-construction-of-underground-stations-for-chennai-metros-line-4

When I look at tenders site I see two Chennai Rail tenders for the given dates but for elevated passages:

https://eprocure.gov.in/cppp/latestactivetendersnew/cpppdata

Specifically:

https://eprocure.gov.in/cppp/tendersfullview/OTEzODA3Mw==A13h1OGQ2NzAxYTMwZTJhNTIxMGNiNmEwM2EzNmNhYWZhODk=A13h1OGQ2NzAxYTMwZTJhNTIxMGNiNmEwM2EzNmNhYWZhODk=A13h1MTYxNDAwNTUxOQ==A13h1Q01STC9QSEFTRS1JSS9DUDEwLUVWLTAzLzIwMjE=A13h1MjAyMV9DTVJMXzYxNzQ2MF8xA13h1OGQ2NzAxYTMwZTJhNTIxMGNiNmEwM2EzNmNhYWZhODk=

https://eprocure.gov.in/cppp/tendersfullview/OTEzOTc1Nw==A13h1OGQ2NzAxYTMwZTJhNTIxMGNiNmEwM2EzNmNhYWZhODk=A13h1OGQ2NzAxYTMwZTJhNTIxMGNiNmEwM2EzNmNhYWZhODk=A13h1MTYxNDAwNTUxOQ==A13h1Q01STC9QSEFTRS1JSS9DUDA4LUVWLTAxLzIwMjE=A13h1MjAyMV9DTVJMXzYxNzY5Nl8xA13h1OGQ2NzAxYTMwZTJhNTIxMGNiNmEwM2EzNmNhYWZhODk=

Urban Transport News is not the only site reporting the tenders:

(one of them): https://www.tenderasian.com/tender-brief/14820394