Canadian Pacific (TSX:CP) spokesman Ed Greenberg says a locomotive and seven cars carrying oil left the tracks Friday afternoon in the city that straddles the Alberta-Saskatchewan boundary.
Greenberg says the train was moving out of a rail yard at the time and wasn't on the main line.
RCMP in Lloydminster say nothing spilled from the cars and no evacuations were necessary.
Some diesel spilled from the locomotive but police say it was contained.
Greenberg says no one was injured and the public was never at risk.
"A full investigation is being conducted to determine what took place — not just the cause, but the circumstances that led to the cause," Greenberg said Saturday.
RCMP say the investigation is being turned over to CP police.