Three Bridges railway station was evacuated after fire broke out in two train carriages.
Fire crews were called to the smouldering freight train carriages at 4.11pm on Friday (April 18).
Firefighters evacuated the station and isolated the electrical supply to the railway.
A spokesman for West Sussex Fire and Rescue Service said seats on the carriages had caught fire accidentally.
The incident caused train delays of up to an hour until 9.30pm.
A spokesman for Southern Rail said: “The current was switched off for around an hour.
“As a result of this, there were delays to Southern services up to 60 minutes, and services were disrupted until around 21.30.”