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
A 15-year-old school boy has been stabbed 'five or six times' on his first day back at school in north London after the summer holidays.
Today's showers should clear overnight - and tomorrow will be more settled, but temperatures still feeling cool.
The pair have been poring over old maps and records in their bid to convince the council the warehouse should not be converted into flats.