Sydney Trains has launched pre-emptive legal action to suspend industrial action, with thousands of rail workers voting on Wednesday to press ahead with a strike.

A hearing has been set down for 3pm in the Fair Work Commission in Sydney, less than an hour after the outcome of a poll of rail workers on whether to call off, or continue with an indefinite overtime ban from Thursday and a 24-hour strike on Monday, was announced.

Of the nearly 6100 rail staff who are members of the Rail, Tram and Bus Union, only 5.93 per cent voted by text message in support of suspending an indefinite overtime ban from Thursday, and a 24-hour-strike on Monday. Any non-responses were counted as "no" votes.

It represents a vote on the Sydney Trains' offer presented to seven unions on Tuesday. It included a 2.75 per cent annual pay rise, a one-off $1000 payment to each employee and the extension of free travel using Opal cards to private and on-demand buses and the new metro train lines when they are opened in the coming years.