On December $19,2019,$ the United Kingdom$$s Network Rail sent out a series of tweets detailing a

signalling control issue that halted rail services the previous day for over an hour. The Southern Rail,

which handles over $7,000$ passenger and freight services daily, experienced a $20-$second power surge

that knocked out four signalling control stations at one of their busiest sections.

Technicians were sent to manually reset systems that automatically shut down in order to protect from

any surge damage. Backup power supplies never kicked in because there was still power, and UPS

systems provided no surge protection.

$($Network Rail continues to investigate how to prevent such a surge from impacting the systems in the

future.$)$

The tweets and subsequent website post have received acclaim from many people. Affected

customers in particular praised Network Rail$$s clear apology, the candid explanation of what

happened, and their next steps in investigating and preventing recurrence. Outline the key phases of the problem management implementation project and explain each phase

in relation to the case above?