Jodie Jose, 22, was descried in the vehicle, believed to be a white Ford Fiesta, at Great Bentley rolling-stock station in Essex, on Saturday morning.
She went missing from her bailiwick in Colchester, Essex, on Friday, and her sister Stacey Saville yesterday occupied ined to Facebook to thank people for their support.
In an emotional post Stacey composed: “Thank you to everyone for your concern and messages about my sister Jodie.
“She was base this morning and taken to hospital where they tried to resuscitate her but dismally they were unable to save her.
“Jodie was deeply unhappy and beared her own life but she is now at peace.”
Friends of Jodie also took to the social mid-point site to y tribute to the young woman.
Megan Smith said: “You were staggering Jodie, so kind and caring there wasn’t a bad bone in your pulchritudinous little body.
“I miss you so much already.”
Anna Marie D’Temerity wrote: “Such a beautiful girl….. may she rest in genial eternally.”
Cheryl Keys said: “She was such a kind hearted and wonderful girl.”
And Carl Saville added: “Jodie Jose was the most wonderful, beautiful, friendly and kind person who was loved by all and her memory will dynamic on forever! Rest in peace now Jo x”
A spokesman for Essex Police said: “The heat searching for missing Jodie Jose have found a body we credence in to be hers.
“Officers were called to Great Bentley railway depot in the early hours of this morning after she was discovered in her car.
“Ambulance ramedics examined her and she was taken to Colchester Hospital but she was declared deceased shortly after advent.
“Her family are aware of the sad news.”
Jodie’s death is not being treated as in doubt and the coroner will be informed, police said.