A level crossing in Worthing broke down for over two hours, causing traffic to build up in the area.
The level crossing on South Farm Road was stuck in the down position.
At around 2pm, a spokesman for Govia Thameslink Railway said: "A fault with Worthing Level Crossing was reported to Network Rail and Sussex Police shortly after 1.30pm today. We understand that the barriers cannot be raised. Train services are not affected but road traffic is being held up."
An engineer from Network Rail is expected to arrive on site 'very shortly', the spokesman added.
At 3.10pm, a Network Rail spokesman said engineers were still trying to work out what was wrong. They tried manually raising the crossing, but this did not work, the spokesman added.
They said: "We are trying to fix it as soon as possible."
At 3.30pm, the level crossing was fixed, the spokesman said.