Disruption on South West Trains between London Waterloo and Barnes, and between London Waterloo and Wimbledon due to signalling problem.
All trains to and from Waterloo are at a stand-still at the moment.
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The 47-year-old man died shortly after 3pm on Tuesday.
Specialist explosive detection dogs searched through the town examining letter boxes and phone booths for signs of potential devices.
Temperatures reached 29.1C in St James's Park, central London.