One appliance and crew from Aylesbury attended.
Two cars had been involved in a collision on the road over a railway bridge.
One woman, injured, and one man, uninjured, were out of the cars when they arrived.
South Central Ambulance Service cared for the woman.
The firefighters made the scene safe. One of the cars had made contact with the brickwork of the bridge. Although there was no obvious damage to the bridge, the firefighters requested Network Rail be notified.
Thames Valley Police also attended.