Peter Austin, managing director for London Overground Rail Operations Limited (LOROL), said:
"We are disappointed by the result of the ballot, but would highlight that fewer than half of our 124 conductors voted, and only 43% of those voted in favour of industrial action.
"We believe industrial action is unnecessary. LOROL continues to give the RMT assurances on employing conductors in alternative customer service roles and offering a generous voluntary redundancy package to those who want it.
"We urge the RMT to work with us to maintain progress in safeguarding jobs and avoid disruption to passengers."
More top news
The British Transport Police have released CCTV images of two men they would like to speak to regarding the incident.
Murdered teen model Sally Anne Bowman would "still be alive" if it hadn't been for Spanish police, according to a man wrongly jailed.
Black Friday could kick off the biggest ever weekend of shopping in the UK with bargain hunters predicted to spend almost £8 billion.