The 29-year-old, who played Jo Sudgen in the ITV soap between 2005 and 2008, had the Staffordshire bull terrier thrust in her face by three people on a train journey to Manchester, with one commanding the animal to "get her", according to The Sun.
Guards came to Pallett's defence after she pulled the empty carriage's communication cord, but the gang fled at a train station.
"They started out by calling her by her Emmerdale name and their abuse got nastier and nastier," a friend said. "They started saying how she must think she's better than everyone else because she chose to ignore them. She was petrified and thought the dog was going to rip her to pieces."
Pallett gave a statement to British Transport Police at the end of her journey.
A spokesman confirmed that they are investigating "abusive behaviour".
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