<Li> Canadian Pacific acquired the Delaware and Hudson in 1991 </Li> <Li> Canadian National acquired the Illinois Central in 1999 </Li> <Li> CSX and Norfolk Southern acquired most of the Conrail freight rail assets in 1997 . </Li> <P> In 1995, when most of the ICC's powers had been eliminated, Congress finally abolished the agency and transferred its remaining functions to a new agency, the Surface Transportation Board . </P>

How many years did it take for the united states to complete its spread across north america