As per reports, Southern Rail has announced on its website that disruptions between Havant and Chichester are expected to continue until the end of the day on Monday (06 January).

• Officials have reported a fault in the signaling system between Havant and Chichester, resulting in reduced train operations on certain lines. Consequently, trains may be canceled or delayed by up to 15 minutes, with services in the opposite direction also affected due to crew and stock displacement.
• Track circuits, part of the fail-safe signaling system used to detect train positions, may fail by indicating a train’s presence even when absent, requiring drivers to stop at red signals, obtain verbal permission from the signaller, and proceed at significantly reduced speeds.
• Train services between Brighton and Southampton, as well as Brighton and Portsmouth Harbour or Portsmouth & Southsea, will operate on an hourly schedule, with alternate trains terminating and restarting at Chichester or Bognor Regis, respectively.