), ▁and ▁oper ates ▁on ▁the ▁ra ck ▁and ▁ad hes ion ▁principle , ▁using ▁sections ▁of ▁R ig gen bach ▁ra ck ▁to ▁overcome ▁the ▁ste eper ▁grad ients ▁enc ount ed ▁on ▁the ▁approaches ▁to ▁the ▁Br ün ig ▁pass , ▁but ▁with ▁most ▁of ▁the ▁line ▁operated ▁by ▁normal ▁ad hes ion ▁methods . ▁The ▁line ▁is ▁elect r ified ▁using ▁the ▁standard ▁Swiss ▁main ▁line ▁system ▁of ▁ 1 5 ▁k V , ▁ ▁H z ▁AC , ▁delivered ▁by ▁overhead ▁line . ▁The ▁line ▁has ▁maximum ▁grad ients ▁of ▁ 1 2 %, ▁using ▁the ▁ra ck , ▁and ▁ 3 %, ▁using ▁simple ▁ad hes ion . ▁ ▁The ▁route ▁is ▁ ▁long . ▁It ▁consists ▁mostly ▁of ▁single ▁track ▁with ▁passing ▁loops ▁at ▁most ▁stations , ▁although ▁the ▁section ▁between ▁Luc erne ▁and ▁Her g is w il , ▁which ▁is ▁shared ▁with ▁the ▁Lu z ern – St ans – Eng el berg ▁line , ▁is ▁mostly ▁double ▁track . ▁For ▁much ▁of ▁the ▁distance ▁between ▁Luc erne ▁and ▁Hor w , ▁one ▁of ▁these ▁two ▁tracks ▁is ▁dual ▁gauge , ▁allowing ▁standard ▁gauge ▁fre ight ▁trains ▁to ▁reach ▁the ▁industrial ▁areas ▁along ▁the ▁line , ▁and ▁the ▁E ich hof ▁bre wer y . ▁ ▁The ▁steam ▁locomot ives ▁G ▁ 3 / 4 ▁and ▁H G ▁ 3 / 3 ▁can ▁operate ▁on ▁the ▁ra ck ▁sections ▁only ▁in ▁the ▁forward ▁direction , ▁hence ▁tur nt ables ▁are ▁needed . ▁The ▁historic ,