A frustrated motorist – late for a back shift – lost his temper with another driver who he thought was taking too long to blow up his tyres.
George Thomson (50), shouted and swore at the other motorist who was using the forecourt tyre inflator.
The commotion was heard by other motorists and the kiosk attendant, and police were called.
The incident happened at Morrisons’ supermarket petrol station in Stirling on July 23 last year the city’s sheriff court was told.
Thomson, a £35,000-a-year ScotRail manager, of Redding Road, Westquarter, denied using threatening and and abusive behaviour.
His mother Isobel Thomson (78), said in evidence that the other driver had remained at the air pump for “four or five minutes” after completing the inflation of his four tyres.
But she insisted: “Our George was cool as a cucumber about it.”
Sheriff Gillian Wade QC found Thomson guilty of the offence, which she also found was racially-aggravated, after a brief summary trial.
She fined him £600 and told him: “It’s quite clear that frustration got the better of you.”