I maintain files of rail news articles for research purposes. Yesterday, by accident, I came across an article which jogged my memory about this thread.
On February 21, 1988 the New York Times reported on the smoking ban that had taken place the previous Monday (Feb. 15th, 1988) on the Long Island Rail Road and on Metro-North.
The ban was voted in at a meeting of New York's Metropolitan Transportation Authority on Jan 22, 1988. Faced with losing $539 million in Federal funding for the LIRR (why this would be so was not explained), the MTA's LIRR committee voted to prohibit smoking on Long Island Rail Road trains. The Metro-North committee voted to restrict smoking to one-car-per-train but was overruled by the MTA board. Saying they wanted a "uniform policy," the MTA board voted 10-3 to ban smoking on Metro-North trains as well.