Officials said the service suspension, which went into effect at shortly after 11 a.m. Monday, was the result of a fire in the switching tower east of the Jamaica station. The damage is currenlty being assessed.
The only branch not affected by the issue is the Port Washington line.
New York City Transit is honoring LIRR fares between Jamaica, New York and Brooklyn.
The anticipated impact on the evening commute is not yet clear, officials said.