The East Side Access project won't be finished earlier than 2020, and likely sometime between 2021 and 2023.
The cost of the project could now top $10 billion, highlighting the incredible complexity of the job. The MTA's most recent cost estimate was $8.2 billion.
The project would eventually allow the LIRR to send trains into an area just north of Grand Central Terminal.
It would save LIRR commuters as much as 40 minutes a day. Currently they have to take the train from Long Island to Penn Station, then commute back to the East Side of Manhattan.
But the project has been plagued by delays and cost overruns.
In other news, MTA officials also say the number 7 subway line extension to the West Side will be delayed around three months. It is now expected to open by Sept. 2014
The MTA board will hold its monthly meeting Wednesday morning.