The incident involved an eight-carriage London Overground service at Enfield Town station during the morning rush hour on Tuesday.
Images posted on social media showed the train remained upright but came off the tracks and stopped just short of hitting a station building.
One commuter said there was “chaos” as services were suspended between Enfield Town and Edmonton Green.
He tweeted: “Just been there & chaos at the door. Train arrived at Enfield Town & crashed into the buffers.
“Fortunately didn’t go through the station window.”
About 50 people were evacuated from the train by Transport for London (TfL) staff before emergency services arrived, London Fire Brigade said.
Station Commander Jim O’Neill, who was at the scene, added: “The train had hit the buffers at the station, which is at the end of the line, and gone up over the top of them.
“Firefighters carried out a systematic search of the train to ensure there were no further people on board.
“Crews assisted station staff to make the scene safe and a recovery operation will now be carried out.”
The brigade said three fire engines and two fire rescue units were called to the scene at 8.27am and it was over for firefighters an hour later.
A London Ambulance Service spokeswoman said: “We were called at 8.16am this morning to reports of a train derailed at Enfield Town railway station, Enfield.
“We sent a number of resources to the scene: one ambulance crew, an emergency planning officer, a clinical team manager, two incident response officers, medics in cars, and our hazardous area response team.
“Two people were assessed at the scene for minor injuries, but they were not taken to hospital.”