The likelihood of Sydney commuters experiencing major delays to train services from Thursday has grown significantly after union bosses declared they were "still miles away" from resolution of a pay dispute.

Sydney Trains' top brass met union officials on Monday to discuss the terms of a new four-year enterprise agreement. The meeting was delayed for several hours after a new Waratah train hit a buffer stop at the end of the rail line at Richmond station in Sydney's north-west, injuring as many as 16 people shortly before 10am.

Rail Tram and Bus Union state secretary Alex Claassens​ said the talks about the terms of a new enterprise agreement were likely to go late into Monday evening as the two sides "are still miles away" from reaching any deal.

"We are still trying to work through the issues. And we are still not talking money until the end," he said.