Samuel Freeland had been awarded a commendation for his bravery in tackling a shoplifter armed with a hypodermic needle.
However, it was the police community support officer (PCSO) who was in the dock after committing the "catastrophic" attack on the 19-year-old woman.
The 23-year-old had targeted the woman as she walked alone through a town centre after a night out.
He then invited her back to his home where he gave her a glass of wine which a jury was told may have contained a crushed up sleeping pill.
He then raped her.
He had been prescribed the medication just days earlier.
Freeland was one of the first PSCOs to be deployed at Reading train station as a member of British Transport Police, in May 2008
Just four months after starting he and a colleague tackled a shoplifter and was threatened by the man with a hypodermic needle.
They both received certificates of commendation from the BTP's London North Area commander Chief, Superintendent Mark Newton.
Freeland was described at the time as "very dedicated."
He was suspended for gross misconduct after the allegation was made to police in March 2011 and resigned five months later.
A spokesman for British Transport Police, Simon Letouze, said: "BTP's professional standards department was informed of the Thames Valley Police investigation and as a result, Mr Freeland was suspended.
"He later resigned from the organisation."
Freeland, from Mason Street, Reading, Berks., was convicted of raping the teenager after six-day trial at Reading Crown Court. He had denied the offence.
Detective Constable Pete Watts of Thames Valley Police said after his sentencing: "The victim was deliberately targeted by Freeland.
"His actions have been catastrophic for her and it is fortunate that she had had the unconditional support of her friends and family throughout the ordeal.
"It is appropriate that we recognise both her bravery in facing the court and the dignity she has shown throughout the trial.
"This was not an easy case for the jury to decide upon.
"Thames Valley Police carefully investigates every report of this nature and where sufficient evidence exists the Crown Prosecution Service seeks a prosecution."
Baljit Ubhey, Chief Crown Prosecutor for the Thames and Chiltern Prosecution Service said: "I hope that this outcome gives some sense of closure to the victim."