Subhash Ramanuj, who had climbed out of his cab to close a jammed door at King's Cross last December, watched 'in horror' as it accelerated away after he had broken a vital safety rule, Snaresbrook Crown Court had been told.
The 35-year-old had hung a heavy bag on a handle, which disengaged a brake control.
Passing sentence, Judge Derek Inman told Ramanuj, of Hanwell, west London, that the case was 'very unusual'.
He went on: 'Our railways and underground networks have the responsibility of carrying perhaps millions of people each day.'
For that reason, the system's very efficient safety procedures had to be followed to the letter to ensure safety of passengers and staff, he said.
By hanging his bag on the 'deadman's handle' which controls the traction brakes, Ramanuj had left the train in full motoring position when he climbed on to the platform.
His train, with 80 passengers aboard, careered driverless for one and a half miles along the Piccadilly Line, speeding through Caledonian Road station and passing a red signal light at up to 60 mph.
It was brought to a halt by an automatic safety device.
At an earlier hearing, the jury, who convicted Ramanuj of wilfully endangering the safety of passengers by failing to operate a safety device, was told that the driver initially told superiors his train had been hijacked.
One passenger told the court that Ramanuj was 'extremely frantic. . .
gesticulating as he ran after the train'.
London Underground said Ramanuj had been dismissed some months ago.Reuse content