üs li ▁section , ▁including ▁the ▁proposed ▁R uck hal de ▁T unnel , ▁which ▁was ▁approximately ▁ 7 0 0 ▁met re - long , ▁was ▁the ▁most ▁complex ▁and ▁largest . ▁A part ▁from ▁the ▁construction ▁of ▁the ▁new ▁track , ▁further ▁work ▁was ▁necessary . ▁Thus , ▁the ▁overhead ▁line ▁voltage ▁was ▁raised ▁to ▁ 1 5 0 0   V ; ▁previously ▁it ▁had ▁been ▁ 1 0 0 0   V ▁on ▁the ▁Tro gen ▁Railway ▁and ▁ 1 5 0 0   V ▁on ▁the ▁St . ▁G allen - G ais - App enz ell ▁Railway . ▁Te ufen ▁station ▁received ▁a ▁third ▁platform ▁track , ▁so ▁that ▁besides ▁the ▁cross ings ▁of ▁the ▁regular ▁interval ▁services , ▁trains ▁can ▁reverse ▁there ▁in ▁the ▁peak . ▁The ▁s iding ▁to ▁St . ▁G allen ▁AB ▁station ▁was ▁replaced ▁by ▁a ▁c ros so ver ▁and ▁the ▁double ▁track ▁was ▁extended ▁from ▁the ▁R ath aus ▁( town ▁hall ) ▁to ▁the ▁St . ▁Leon hard ▁bridge . ▁In ▁order ▁to ▁simplify ▁operation , ▁the ▁seven ▁signal ▁boxes ▁between ▁Nieder te ufen ▁and ▁Tro gen ▁have ▁been ▁replaced ▁by ▁two ▁new ▁systems , ▁which ▁contain ▁components ▁of ▁the ▁Si Grid ▁inter lock ing ▁architecture , ▁developed ▁by ▁S iem ens . ▁Si Grid ▁connect s ▁the ▁external ▁facilities ▁with ▁the ▁inter lock ing ▁and ▁supplies ▁it ▁with ▁ 7 5 0 ▁Vol t ▁DC ▁power . ▁▁ ▁The ▁cross - city ▁line ▁brings ▁significant ▁improvements ▁to ▁passengers