John Wetherald, 51, relieved himself after being found moments earlier lying in the entrance, surrounded by cans of booze.
Wetherald, of Lewis Crescent, Hendon, committed the crime after being seen by paramedics called amid concerns for his wellbeing.
Magistrates heard most of his 144 previous criminal convictions were booze-related – and he owes the courts over £7,000 in fines and costs.
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They have now added another £239 to his tally after he was fined £120, with £85 court costs and a £34 victim surcharge.
Prosecutor Leanne Duffy told the South Tyneside hearing: “Around 11am, officers were called to Sunderland railway station.
“The defendant was lying on his back, with several cans of alcohol on the ground.
“His speech was slurred, he smelled of alcohol and he was unsteady on his feet.
“An ambulance was requested to check him out. He has then unbuttoned his trousers and started to urinate in full public view.
“There were young people there, and mothers and the elderly. He then urinated on an officer’s boots.
“He has 144 previous convictions from 272 offences, many for alcohol and the last in February.”
Wetherald attended the court but was denied access by staff who suspected he was drunk.
Val Bell, defending, entered a guilty plea to a charge of drunk and disorderly on his behalf.
She said: “I went out to see him and he was able to provide instructions.
“It’s right that he’s had an alcohol addiction for many years.
“He’s sorry for what happened, it was out of order. I would ask you to give full credit for an early guilty plea. He has attended court today.”
Chair of the bench Gary Cracknell said magistrates would have liked to have imposed a sentence which would offer support to Wetherald.
But he conceded sentencing guidelines meant their hands were tied and their best option was to fine him.
Mr Cracknell described Wetherald’s level of fines as “extreme”, and added of his sentencing powers: “I’d like to help but apparently I can’t.”