The Labour Party says large offices in Dublin should stagger their working hours to relieve pressure on commuter trains.
It will be 2022 at the earliest before new carriages will be delivered to Dublin, where there is heavy overcrowding at rush hour.
Labour's transport spokesman Senator Kevin Humphreys said the situation was at the point where 9am start times may have to be changed.
"Our primary schools could change their start times to try to avoid rush hour for parents," he said.
"Our civil servants have to look at that...Our big employers like Google - who employ 8,000 people in the city centre - maybe (also) have to look at staggering their start times."
Meanwhile, Senator Humphreys said Transport Minister Shane Ross had held off on buying new trains for too long, and that passenger safety is being impacted on crowded carriages.
Senator Humphreys said he saw a fellow passenger faint on a packed Dart just last week.
"A young lady fainted at Blackrock, but only hit the floor at the Grand Canal Dock station. They were packed in like sardines, and the pressure of the crowd kept this young lady upright," he said.
"Minister Ross has delayed weeks and months in ordering 41 new carriages, that will assist with the overcrowding.
"There has been delay after delay."