A solid strike by train drivers at Arriva Trains Wales had a big impact as hundreds of services were cancelled on Monday.
Their refusal to work overtime on Sunday also led to disruption across the firm’s network. Further strikes could follow.
Some 70 percent of drivers, who are members of the Aslef union voted for strikes over pay, while 80 percent voted for action short of strikes.
Workers also took unofficial action late last year.
Peter Leppard, the firm’s operations director, has angered strikers.
When asked why train drivers in Wales should be paid less than train drivers in other parts of Britain he replied, “It’s the difference between driving a jumbo jet and a milk float.”
Drivers in the RMT union struck solidly over pay and conditions on 27 December, though the union called off a further day of action this month after the company threatened it with a court injunction.
RMT and Aslef members must stand together to defeat the company and any court threats to their battle.
Cleaners in the RMT transport union struck at First Great Western depots in Cardiff and Swansea on Friday of last week over pensions, payment of wages and lack of communication.
The strike followed a 100 percent vote for action by cleaners employed by the Mitie company.
Workers complain of wage discrepancies, leaving many shortchanged.
They are also angry at the lack of pensions contributions by the firm. This was their second one‑day strike.