Editor’s note: This story is part of a collaboration between Flatwater Free Press and The Reader examining Omaha’s future streetcar. Ernest Wintroub ushered his 7-year-old son Frank out the door of their Dundee home on a brisk spring evening in 1955. They stood on the street corner and listened for the familiar rumbling. For 86 years, streetcars had crisscrossed Omaha. That night was the final public ride for the city’s last operating trolley,…