The teenager killed after being struck by a train in Yarnbrook on Wednesday, January 15, has been named locally as Mary Stroman.
The 16-year-old, who is understood to have been staying in the area, was hit near the Aintree Avenue crossing at around 8.20pm.
Before the incident Wiltshire Police were called to the area investigating a report of a missing person.
It is believed the teenager is the person they were trying to find.
British Transport Police is leading the investigation into how it happened. Any witnesses can call BTP on 0800 40 50 40, quoting incident 520 of January 15.