▁ 2 0 1 1 , ▁in ▁the ▁Railway ▁Order ▁was ▁granted ▁for ▁the ▁development . ▁The ▁grant ing ▁of ▁the ▁Railway ▁Order ▁permitted ▁both ▁the ▁construction ▁of ▁the ▁scheme ▁and ▁any ▁necessary ▁comp uls ory ▁ac quisition ▁of ▁property . ▁It ▁did ▁not ▁however ▁commit ▁fund ing ▁to ▁the ▁project . ▁ ▁In ▁September ▁ 2 0 1 5 , ▁it ▁was ▁announced ▁that ▁the ▁project ▁had ▁been ▁cancel led ▁in ▁favour ▁of ▁a ▁simpler ▁alternative . ▁However , ▁it ▁was ▁planned ▁to ▁return ▁as ▁part ▁of ▁a ▁future ▁D ART ▁Exp ansion ▁Program me , ▁starting ▁no ▁earlier ▁than ▁at ▁least ▁ 2 0 2 0 ▁or ▁ 2 0 2 1 . ▁ ▁As ▁of ▁ 2 0 1 6 , ▁the ▁National ▁Transport ▁Author ity ▁( N TA ) ▁was ▁review ing ▁the ▁D ART ▁Under ground ▁project , ▁with ▁a ▁view ▁to ▁exam ining ▁the ▁design ▁of ▁the ▁t unn els , ▁and ▁undert aking ▁feas ibility ▁studies ▁to ▁see ▁if ▁it ▁would ▁be ▁possible ▁to ▁use ▁single - b ore ▁t unn eling ▁as ▁opposed ▁to ▁tw in - b ore ▁t unn eling . ▁ ▁In ▁September ▁ 2 0 1 7 , ▁it ▁was ▁suggested ▁that ▁this ▁review ▁would ▁complete ▁early ▁in ▁ 2 0 1 8 , ▁and ▁that ▁- dep ending ▁on ▁the ▁outcome ▁of ▁the ▁review - ▁works ▁on ▁the ▁project ▁would ▁not ▁commence ▁until ▁at ▁least ▁ 2 0 2 0 . ▁Re vised ▁pro jections ▁suggested ▁that ▁it ▁would ▁be