Rail Accident Investigation Branch
At around 17:43 hrs on Friday 5 May 2023, a northbound Northern Line train departing from Clapham Common station was halted by the operation of a passenger emergency alarm. This alarm was operated after passengers within the train became aware of a burning smell. The train came to a stand with one car fully and another car partially inside the tunnel. The remaining four cars forming the train remained fully in the platform.
The doors of the train remained closed after it came to a stand. Within a short space of time, there was an uncontrolled evacuation of passengers from the train and onto the platform. Passengers exited the train via windows which had been broken open and the interconnecting doors between cars on the train. Other passengers subsequently exited the train after station staff opened the trains bodyside doors.
No serious injuries resulted from the evacuation but at least one passenger reported cutting their hands when exiting the train.
The London Fire Brigade attended the station following the incident and found no evidence that there had been a fire. London Underground maintenance staff later determined that the probable cause of the burning smell related to the trains braking system.
Our investigation will seek to identify the sequence of events that led to the incident. It will also consider:
- the actions of those involved and anything which may have influenced them
- London Undergrounds procedures for incident response and management of out-of-course events
- the arrangements in place to manage and control the risks of a suspected fire on a London Underground train
- the design and maintenance of the braking system on the train
- any underlying management factors.
Our investigation is independent of any investigation by the railway industry or by the industrys regulator, the Office of Rail and Road.
We will publish our findings, including any recommendations to improve safety, at the conclusion of our investigation. This report will be available on our website.
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