On a delayed train from Manchester to London's King's Cross station, Rowling came up with the idea for "Harry Potter." Over the next five years, she outlined the plots for seven books in the series, writing in longhand and amassing scraps of notes written on different papers. Back in the early 90s, JK Rowling was a young, unemployed single mother on welfare desperate to make ends meet. One day, while riding the train back and forth between London and Manchester for.