Train services in Sussex are subject to delays this morning (Monday, October 29)
A fault with the signalling system at Haywards Heath means that fewer trains are able to run on some lines, Southern said.
The company said train services running through this station may be delayed by up to 10 minutes.
Disruption is expected until 9am
Services travelling through Haywards Heath may encounter some delays.
Southern said use of platform 4 at Haywards Heath will be avoided and services will be diverted into alternative platforms where possible.
This is likely to cause congestion and delays through the station in both directions, it added.
On the roads there is slow traffic on the A259 Bognor Road westbound from Elbridge Avenue to A27 Chichester Bypass (Bognor Bridge Roundabout).
There is also slow traffic on the A27 Chichester Bypass both ways from A259 (Fishbourne Roundabout) to A285 (Portfield Roundabout).