Alaska Railroad (http://www.akrr.com)
Association of American Railroads (http://www.aar.org/)
American Short Line & Regional Railroad Association (http://www.aslrra.org)
Amtrak (http://www.amtrak.com)
British Columbia Railway Company (BC Rail)  (http://www.bcrail.com/bcr/) 

Burlington Northern Santa Fe (http://www.bnsf.com/)
Canadian National Railway Corporation (http://www.cn.ca/)
Canadian Pacific Rail System (http://www.cpr.ca)
Canton Railroad (http://www.cantonrr.com/)
Columbus & Greenville Railway (http://www.cagy.com/cgrail.htm)

Conrail (http://www.conrail.com/)
CSX Transportation (http://www.csx.com/)
Dakota, Minnesota & Eastern Railway (http://www.dmerail.com)
Ferrocarril Mexicano (http://www.ferromex.com.mx)
Guilford Rail System (http://www.guilfordrail.com) 

I&M Rail Link (http://www.imrail.com)
Illinois Central (http://www.icrr.com/)
Kansas City Southern Industries (http://www.kcsi.com/)
Long Island Rail Road (http://www.mta.nyc.ny.us/lirr/index.html)
METRA Rail (http://www.metrarail.com/)

Metro North Commuter RR (http://www.mta.nyc.ny.us/mnr/)
Montana Rail Link (http://www.montanarail.com)
Norfolk Southern (http://www.nscorp.com)
Northern Indiana Commuter Transp. District (http://www.nictd.com/)
Ontario Northland (http://www.ontc.on.ca/)

PATH (Port Authority Trans-Hudson)  (http://www.nj.com/njtransit/path.html)
RailAmerica (http://www.railamerica.com)
Shortline Services (http://www.shortlineservices.com/)
Texas Eagle (http://www.texaseagle.com/)
Texas-Mexican Railway (http://www.kcsi.com/tmr.html)

Union Pacific Railroad (http://www.uprr.com/)
Via Rail Canada, Inc. (http://www.viarail.ca/)
Wheeling & Lake Erie Railway (http://www.wlerwy.com)
White Pass & Yukon Railway  (http://www.whitepassrailroad.com/)
Wisconsin Central Railroad (http://www.cn.ca/wc)