Being a Long Islander, trolley lines that operated on Long Island are my favorites, especially these:
New York & North Shore Railway;
New York & Long Island Traction Company;
Huntington Railroad;
Manhattan & Queens Traction Company;
New York & Queens County;
Brooklyn & Queens Transit;
Northport Traction Company
My favorite street car / trolley car historian is Vincent Seyfried who was my high school English teacher.
Lets see your favorite traction lines.