<P> By the summer of 1868 , the Central Pacific ( CP ) had completed the first rail route through the Sierra Nevada mountains , and was now moving down towards the Interior Plains and the Union Pacific ( UP ) line . More than 4,000 workers , of whom two thirds were Chinese , had laid more than 100 mi ( 160 km ) of track at altitudes above 7,000 ft ( 2,100 m ) . In May 1869 , the railheads of the Union Pacific and the Central Pacific railroads finally met at Promontory Summit , Utah Territory . A specially - chosen Chinese and Irish crew had taken only 12 hours to lay the final 10 mi ( 16 km ) of track in time for the ceremony . </P>
<P> By the summer of 1868 , the Central Pacific ( CP ) had completed the first rail route through the Sierra Nevada mountains , and was now moving down towards the Interior Plains and the Union Pacific ( UP ) line . More than 4,000 workers , of whom two thirds were Chinese , had laid more than 100 mi ( 160 km ) of track at altitudes above 7,000 ft ( 2,100 m ) . In May 1869 , the railheads of the Union Pacific and the Central Pacific railroads finally met at Promontory Summit , Utah Territory . A specially - chosen Chinese and Irish crew had taken only 12 hours to lay the final 10 mi ( 16 km ) of track in time for the ceremony . </P>
at promontory point utah where the central pacific and union pacific
at promontory point utah where the central pacific and union pacific
railroads finally met
railroads finally met