Th Mtr Tnnl, frmrly knwn s Mlbrn Mtr Rl (MMR), s n ndrgrnd rpd trnst prjct crrntly ndr cnstrctn n Mlbrn, Vctr, strl. t nvlvs th cnstrctn f twn 9-klmtr (5.6 m) rl tnnls btwn Sth Knsngtn (nrth wst f th Mlbrn cntrl bsnss dstrct) nd Sth Yrr (n th sth st) wth fv nw ndrgrnd sttns. Th tnnl wll cnnct th Pknhm nd Crnbrn lns wth th Snbry ln, crtng nw hgh-frqncy crss-cty ln tht bypsss Flndrs Strt sttn nd th Cty Lp. Th ln s ls plnnd t srv Mlbrn rprt v nw brnch ln wst f Snshn.
Th prjct wll nbl th prtnl sprtn f vrs xstng lns n Mlbrn's rl ntwrk nd ncrs th cpcty f th systm t mtr-styl frqncs. Th Mtr Tnnl hs hgh-cpcty sgnllng nd pltfrm scrn drs, bth frst fr Mlbrn.
Th stt gvrnmnt bgn plnnng th prjct n 2015. ntl cnstrctn wrks cmmncd n rly 2017. Sctns f th Mlbrn cntrl bsnss dstrct, ncldng Cty Sqr nd prts f Swnstn Strt, wr clsd t nbl cnstrctn f th tnnl nd sttns. Tnnllng bgn n 2019 nd ws cmpltd n 2021. rgnlly xpctd t b cmpltd n 2026, th Mtr Tnnl wll pn n 2025. Th prjct s bng dlvrd by th Vctrn nfrstrctr Dlvry thrty, t n stmtd cst f $12.8 blln.