Workers from the Tyne and Wear Metro are on strike in a dispute over pay and working conditions.
The action is expected to affect thousands of commuters as all today's Metro services are cancelled.
Thousands of commuters are expected to be affected this morning as workers from the Tyne and Wear Metro go on strike.
Talks between RMT Union and Metro operators DBTW broke down on Monday, resulting in strike action today and June 21.
The strike is also expected to affect around 20,000 people travelling to see Coldplay perform at the Stadium of Light this evening.
Thirty extra buses have been put into service to ease demand on other modes of public transport.
The RMT Union says it had no option but to call for strike action on the Tyne and Wear Metro this month.
Workers have proposed strike action on June 7 and 21 - the same dates as planned Coldplay and Bruce Springsteen concerts at the Stadium of Light.
The disruption is expected to affect people travelling to the stadium, as well as thousands of commuters getting to and from work.
Union bosses say they risk losing public support by holding the strikes, but that it was their only option.
Micky Thompson from RMT Union said: "We've tried to negotiate with the employer. The employer has closed the doors and made their position clear. There is no further amendment.
"We have to taken it to our membership. Our membership have said it's not acceptable and we want to do something about it.
"The situation with the concerts has come up. It's given us a position of strength and we've utitlised this to our advantage. Hence why discussions have now been forthcoming for June 4.
"So hopefully sense will prevail and they'll come back and offer something substantial in respect of rates and pay and conditions of service, and we won't have to disrupt the concerts."