<P> Principally designed and built under the personal , often on - site direction of CPRR 's Chief Assistant Engineer , Lewis M. Clement ( 1837 -- 1914 ) , the original ( Track 1 ) summit grade remained in daily use from June 18 , 1868 , when the first CPRR passenger train ran through the Summit Tunnel , until 1993 when the Southern Pacific Railroad ( SP ) ( which operated the CPRR - built Oakland - Ogden line until its 1996 merger with the Union Pacific Railroad ( UP ) ) abandoned the 6.7 mile ( 10.7 km ) section of Track # 1 over the summit running between the Norden complex ( Shed 26 , MP 192.1 ) and the covered crossovers in Shed # 47 ( MP 198.8 ) , one mile east of the old flyover at Eder . All traffic has since operated over the Track # 2 grade crossing the summit 1 mile ( 1.6 km ) south of Donner Pass through the 10,322 - foot ( 3,146 m ) - long Tunnel # 41 running under Mount Judah between Soda Springs and Eder . SP made this change because the railroad considered Track 2 and Tunnel 41 ( which was opened in 1925 when the summit section of the grade was finally double tracked ) to be easier and less expensive to maintain during in the harsh Sierra winters than the Track 1 tunnels and snow sheds over the summit . </P>
<P> Principally designed and built under the personal , often on - site direction of CPRR 's Chief Assistant Engineer , Lewis M. Clement ( 1837 -- 1914 ) , the original ( Track 1 ) summit grade remained in daily use from June 18 , 1868 , when the first CPRR passenger train ran through the Summit Tunnel , until 1993 when the Southern Pacific Railroad ( SP ) ( which operated the CPRR - built Oakland - Ogden line until its 1996 merger with the Union Pacific Railroad ( UP ) ) abandoned the 6.7 mile ( 10.7 km ) section of Track # 1 over the summit running between the Norden complex ( Shed 26 , MP 192.1 ) and the covered crossovers in Shed # 47 ( MP 198.8 ) , one mile east of the old flyover at Eder . All traffic has since operated over the Track # 2 grade crossing the summit 1 mile ( 1.6 km ) south of Donner Pass through the 10,322 - foot ( 3,146 m ) - long Tunnel # 41 running under Mount Judah between Soda Springs and Eder . SP made this change because the railroad considered Track 2 and Tunnel 41 ( which was opened in 1925 when the summit section of the grade was finally double tracked ) to be easier and less expensive to maintain during in the harsh Sierra winters than the Track 1 tunnels and snow sheds over the summit . </P>
when did central pacific railroad trains first pass over donner summit
when did central pacific railroad trains first pass over donner summit
June 18 , 1868
June 18 , 1868