The woman who unleashed a racist tirade on a packed peak-hour train is not who she says she is.

In the filmed abuse hurled at passengers, including children and an Asian woman, the alleged offender pretends to talk on the phone to police.

In the mock call she states three times that her name is Sue Wilkins.

But the 55-year-old is actually Karen Bailey from Buff Point, who previously has worked as a legal secretary at some of Sydney's top law firms.