▁Ex position ▁Fly er ▁began ▁on ▁June ▁ 1 0 , ▁ 1 9 3 9 . ▁In ▁the ▁beginning , ▁the ▁train ▁used ▁steam ▁locomot ives ▁as ▁mot ive ▁power ▁and ▁consisted ▁of ▁heavy weight ▁P ull man ▁standard ▁cars . ▁In ▁later ▁years , ▁the ▁train ▁used ▁dies el ▁power ▁and ▁in ▁the ▁final ▁months ▁of ▁service , ▁used ▁stream lined ▁passenger ▁cars . ▁Initial ly , ▁the ▁service ▁was ▁to ▁be ▁temporary , ▁but ▁its ▁popular ity ▁made ▁it ▁a ▁significant ▁rival ▁to ▁the ▁City ▁of ▁San ▁Francisco , ▁the ▁Chicago - O ak land ▁train ▁operated ▁joint ly ▁by ▁the ▁Chicago ▁& ▁North western , ▁Union ▁Pacific ▁and ▁Southern ▁Pacific , ▁and ▁it ▁remained ▁in ▁operation ▁until ▁ 1 9 4 9 . ▁The ▁C B & Q , ▁D & R G W ▁and ▁Western ▁Pacific ▁replaced ▁the ▁Ex position ▁Fly er ▁in ▁ 1 9 4 9 ▁with ▁the ▁all - stream lined ▁California ▁Ze ph yr , ▁which ▁used ▁the ▁same ▁route . ▁ ▁California ▁Ze ph yr ▁ ▁In ▁its ▁original ▁run , ▁California ▁Ze ph yr ▁operated ▁over ▁the ▁Chicago , ▁Bur ling ton ▁and ▁Qu in cy ▁Rail road ▁( B ur ling ton ▁Route ) ▁from ▁Chicago ▁to ▁Den ver , ▁Colorado , ▁the ▁Den ver ▁and ▁Rio ▁Grande ▁Western ▁Rail road ▁between ▁Den ver ▁and ▁Salt ▁Lake ▁City , ▁Ut ah , ▁and ▁the ▁Western ▁Pacific ▁Rail road ▁from ▁Salt ▁Lake ▁City ▁to ▁Oak land , ▁California . ▁C ars ▁owned