Here goes the last letter in the name game.
The "N"s.....
Napierville Junction
Nashua & Lowell
Nashville & Ashland City
Nashville & Chattanooga
Nashville & Decatur
Nashville & Eastern
Nashville & Northwestern
Nashville, Chattanooga & St. Louis
Natchez & Eastern
Natchez Trace
National Railroad Passenger Corp. (Amtrak)
National Railways of Mexico
National Transcontinental
Naugatuk
Nevada & California
Nevada-California-Oregon
Nevada Central
Nevada County Narrow Gauge
Nevada Northern
New Albany & Salem
Newfoundland
New Haven
New Haven & New London
New Haven & Northampton
New Jersey & New York
New Jersey Midland
New Jersey Southern
New London Northern
New Mexico & Arizona
New Orleans & Northwestern
New Orleans Great Northern
New Orleans, Jackson & Great Northern
New Orleans, Jackson & Northern
New Orleans, Mobile & Chicago
New Orleans, Mobile & Texas
New Orleans, St. Louis & Chicago
New Orleans, Texas & Mexico
Newport News & Mississippi Valley
Newton & Northwestern
New York & Boston
New York & Canada
New York & Erie
New York & Greenwood Lake
New York & Harlem
New York & Long Branch
New York & New England
New York & New Haven
New York & Northern
New York & Oswego Midland
New York Central
New York Central & Hudson River
New York, Chicago & St. Louis (Nickel Plate)
New York Connecting
New York, Kingston & Syracuse
New York, Lake Erie & Western
New York, New Haven & Hartford
New York, Ontario & Western
New York, Pennsylvania & Ohio
New York, Philadelphia & Norfolk
New York, Providence & Boston
New York, Susquehanna & Western
New York, Westchester & Boston
New York, West Shore & Buffalo
Niagara Junction
Norfolk & Carolina
Norfolk & Petersburg
Norfolk & Southern
Norfolk & Western
Norfolk County
Norfolk, Franklin & Danville
Norfolk Southern
Norfolk, Virginia Beach & Southern
North Carolina
Northeastern
North Eastern
Northeast Oklahoma
Northern
Northern Alberta
Northern Central
Northern Cross
Northern Electric
Northern Indiana
Northern Michigan
Northern of New Jersey
Northern Ohio
Northern Pacific
North Missouri
North Pacific Coast
North Pennsylvania
North Shore (California)
Northwestern Pacific
That's all folks. Now the promised sources. I used three guides by Kalmback Publications: The Historical Guide to North American Railroads; Guide to North American Steam Locomotives and Diesel Locomotives, The First 50 Years. Also Railroads; The Great Americam Adventure by The National Geographic Society; long out of print. The first three books are very informative with histories of all these RRs, rosters, mergers, equipment, etc.
Have questions about a specific RR? These books are the place to go. Also, I could briefly help you with info too since I already have the books. But go easy on me. Some of these RRs have extensive listings.
Pete AKA Stumpy