Conversation so far:
are there two films called the girl on the train
There are five movies titled The Girl on the Train: a 2016, 2013, and 1927 American film, a 2020 Indian film, and a 2009 French film
are there two books called the girl on the train
The Girl on the Train was written in 2015 by Paula Hawkins and Girl on a Train was written in 2013 by Alison Waines.
did people confuse the girl on the train with girl on a train
Reporter David Benoit told NPR's Linda Wertheimer that an incredible number of people were buying Girl on a Train instead of The Girl on the Train

Question: how
Self-contained rewrite: how did people confuse the girl on the train with girl on a train