I grew up in Floral Park, New York (1946-1965) just up Tyson Avenue (AKA 260th Street) from the Long Island Rail Road. I also have a fascination with Long Island trolley lines. So my favorite railroads of the steam era are:
Long Island Rail Road;
New York & North Shore Traction Company;
New York & Long Island Traction Company;
New York & Queens Traction Company;
Steinway Lines.
I also favor some out-of-town railroads in the steam era for the great steam engines such as:
New York Central;
Norfolk & Western;
Nickle Plate;
New York, Ontario & Western;
Jersey Central;
Southern;
Boston & Maine.
