A railway level crossing is due to be closed all weekend so that a stretch of track can be replaced, with the network operator warning passengers and drivers to plan ahead.
A replacement bus service will run for part of the west coastway line as a result.
And the closure of the Portslade level crossing comes as drivers also face queues caused by temporary traffic lights in Portland Road, Hove close to the bottom of Olive Road.
The crossing dissects Boundary Road, Hove, and Carlton Terrace and Station Road, Portslade.
Network Rail said: “Work to replace railway track on the Portslade level crossing in Boundary Road will close it for two days.
“The closure will begin at 1am today (Saturday 30 November) and is scheduled to be completed by 2am on Monday 2 December.
“Throughout the closure, alternative travel plans will need to be used.
“Southern trains that usually run between London Victoria and Littlehampton will be diverted to terminate at Brighton only.
“Motorists are being told to use the A270 Old Shoreham Road as a diversionary route.
“Buses will operate instead of trains throughout the closure between Brighton and Littlehampton.
“Southern trains that usually run between London Victoria and Littlehampton will be diverted to terminate at Brighton.
“Local bus services 1X, 6 and 46 will all be diverted.
“For pedestrians, the old underpass will remain open.
“A shuttle bus will operate for people unable to use the underpass, picking up and dropping off between Portslade railway station car park, north of the level crossing (next to the cycle hub), and Portslade station (stop C) outside Station Kebab House.
“The shuttle will operate throughout the whole closure of the crossing.”
Lucy McAuliffe, Network Rail’s Sussex route director, said: “To complete the work, we need to close the railway, and as the work is taking place near the level crossing, it needs to close as well.
“We’re asking motorists to leave a bit more time to travel as the diversion will mean slightly longer journeys. Thank you for bearing with us while we work to improve the railway.”
