Tens of thousands of commuters in Dublin are being forced onto alternative transport in the second strike on the Luas network.
Trade union leaders in Siptu said they fear the 48-hour walk-outs will continue for weeks or months after there was no contact with management or mediators in the last week.
The latest stoppage is scheduled to run until Saturday, hitting about 90,000 passengers each day.
Workers’ representatives, who have been championing salary hikes of 8% to 53%, claim pay scales mean drivers can work for nine years and hit a salary of 42,247 euro or 47,941 euro for traffic supervisors.
Transdev, which operates Luas under a contract with the state, has pulled bonuses worth up to 750,000 euro for the workforce of 250 but said it remains open to pay rises albeit closer to the 1-3% mark.
The company is facing penalties of more than 100,000 euro every day services do not run.
Siptu spokesman Owen Reidy said the workers are determined to get some form of pay rise.
“We’d happily dance with anybody but the radio studio is the only place we’ve had talks this week,” he said.
“The workers are determined to get a just outcome and even those who would rather not be on the picket line are serious about reaching an agreement.”
Transdev said the pay claims would cost the company more than 20 million euro over five years.
Transport Minister Paschal Donohoe said he was powerless to offer more money to meet the demands.
A further two strikes are planned, including on St Patrick’s Day.
A spokeswoman for Transdev said: “We have been saying since January that we are willing to engage on pay claims.”