Can anyone tell me the steepest mainline 
    gradients on US transcontinental lines?
     
    I think you'll find them moderately steep - 
    came through the Rockies in 1997 on the California Zephyr and would be 
    surprised if they weren't around 1 in 40 in places.  The Americans have 
    latterly used pretty powerful locos, particularly in the mountainous 
    country.  The Cajun Pass, on UP's line in California is 1 in 36.  
    Suggest you try a posting to misc.transport.rail.americas or alt.railroad, 
    you'll most likely get replies as a percent grade from the 
    locals.
     
    regards
     
    David Bennetts
    Canberra