All passengers have safely disembarked from a train which hit a tree between Barnham and Chichester this morning.
The train has just arrived at Chichester station after debris was removed from underneath the wheels.
Both lines were blocked between Chichester and Barnham following the incident at 8.30am, which smashed the front windscreen of the train.
Passenger Kirsty Woodhams, 22, said: "You could see bits of tree flying out from under where the wheels were crushing it up.
"It wobbled a bit, I'm happy obviously we didn't come off the tracks. It just crunched up the tree and stopped."
She said the driver did well to hit the brakes when he did but she thought it showed the need for a guard, now named onboard supervisors.
The driver said he ducked out the way of the branch as he thought it might hit the driver's side of the cabin, but fortunately it landed to the right.
Kirsty said: "It it had hit him [the driver] and knocked him out, we would have just been sitting here not knowing what to do.
"I think you need a supervisor in any case, especially if the train is moving, like if a fight breaks out or something, you couldn't just stop the train to sort it."
Southern Rail has said disruption to rail services is expected until 3pm. Replacement bus services are in place while the tree is cleared from the line.