Rida Kazem’s Range Rover smashed into a Tesla parked in a dealership by Park Royal station, ending up on the rail tracks.
Yagmur Ozden, 33, who was a passenger in the Tesla, was killed in the high-speed incident just before 4am on August 22, 2022.
The mum-of-one, from North Finchley, had been ejected from the rear seat of the car.
She was pronounced dead at the scene on the A40, and an inquest confirmed she had died from blunt force trauma.
Appearing today at Isleworth Crown Court, Kazem also admitted a second offence of causing serious injury by dangerous driving related to Zamarod Arif.
Meanwhile, Kazem suffered major injuries and spent weeks in a coma at St Mary’s Hospital in Paddington.
The jewellery manager had his left leg amputated and previously appeared in a wheelchair in court.
Prosecutor Nicholas Hearn told the court Kazem has past speeding convictions on his record, including a recent offence for driving 95mph in a 50mph zone before this incident.
But David Rhodes said his client was a ‘young man of otherwise good character’.
He well understands this is a very serious matter and he’s facing a very significant term of imprisonment,’ he added.
Mr Rhodes said the defendant had ‘suffered a serious injury himself’, for which he may have to undergo further surgery.
Judge Robin Johnson adjourned the case and remanded Kazem in custody.
He said: ‘Your case will be adjourned for the preparation of a report on the topic of dangerousness by the probation service and for both parties to gather of information in respect of the prosecution and your mitigation.
‘Your bail is now withdrawn, you will be remanded in custody on both matters.’
Kazem, of Costons Avenue, Greenford, will next appear at the same court on April 21 for sentencing.