Part of the job of the train radio is to carry the train radio alarm
traffic
that notifies the Line Controller in the event that a train becomes
stalled
in a tunnel due to an incapacitated Train Operator (due to EG heart
attack)
I'm not familiar with the Northern stock, but on the Picc. if the
deadman is
released for 60 seconds an alarm starts to sound in the cab. Should
the

Seems like a pretty good system and I guess you can understand why
running
a service without it would be difficult. However .... given that its
virtually impossible
that every radio in all 90 odd trains on the northern died
simultaniously the problem
is obviously at the line controllers end and I can't help wondering why
there wasn't
some sort of limited backup system?

B2003