▁ 1 9 0 4 . ▁The ▁route ▁had ▁seven ▁ra ck ▁sections ▁using ▁the ▁R ig gen bach - K lose ▁system ▁with ▁a ▁total ▁length ▁of ▁ 4 . 9   kil omet res . ▁▁ ▁Elect rical ▁operations ▁at ▁ 1 5 0 0   V ▁DC ▁comm enced ▁on ▁ 2 3   J anu ary ▁ 1 9 3 1 ▁and ▁its ▁name ▁was ▁changed ▁to ▁St . ▁G allen - G ais - App enz ell - B ahn ▁( S GA ). ▁The ▁difficult ▁line ▁with ▁tight ▁b ends ▁demanded ▁new ▁design ▁solutions ▁to ▁enable ▁the ▁BC Fe h   4 / 4 ▁electric ▁rail c ars ▁to ▁operate ▁over ▁both ▁ad hes ion ▁and ▁ra ck ▁sections . ▁Between ▁ 1 9 7 8 ▁and ▁ 1 9 8 3 , ▁five ▁of ▁the ▁six ▁ra ck ▁sections ▁were ▁replaced ▁by ▁new ▁track ▁allowing ▁ad hes ion ▁operations . ▁All ▁that ▁remained ▁was ▁the ▁nearly ▁one ▁kilomet re - long ▁ra ck ▁section ▁through ▁the ▁R uck hal de ▁landscape ▁between ▁St . ▁G allen ▁and ▁Ri eth üs li . ▁ ▁Tro gen ▁Railway ▁ ▁The ▁St . ▁G allen – T ro gen ▁railway ▁( T ro gener bahn , ▁T B ) ▁was ▁opened ▁on ▁ 1 0 ▁July ▁ 1 9 0 3 . ▁Origin ally , ▁the ▁line ▁was ▁elect r ified ▁at ▁ 7 5 0 ▁vol ts ▁DC . ▁The ▁voltage ▁was ▁increased ▁to ▁ 9 0 0