Unfinished Paul Bartel / Mary Woronov film

I was listening to the Projection Booth podcast episode on the film 'Eating Raoul' and Mary Woronov said she and Paul Bartel filmed scenes for a movie together that was never finished. She said their scenes were on a train but can't remember the name of the film or director. I've been trying to figure out what she could have been referring to but have turned up no leads- Does anyone here have any idea what that film might be?