Traffic lights at the London Road level crossing between Priory Road and Mallards Way were stuck on red yesterday, but the barriers were still working.
Engineers reset the barriers after they had fallen which Network Rail says caused the lights to stop working temporarily.
Network Rail spokeswoman Anne-Marie Batson said as part of plans to upgrade the tracks between Bicester Town and Oxford for the East-West rail project, the level crossing is closed to trains.
She said: “Engineers were on site testing the crossing barriers and it is likely that the lights were activated as part of this test.”
She said the problem had been fixed.