More than 100,000 commuters who rely on Long Island Railroad, Amtrak, and New Jersey Transit for their daily commute into Manhattan could be forced to transfer onto subway lines in Brooklyn and Queens if a possible Amtrak strike shuts down Penn Station at the end of the month.

Nine separate labor unions representing Amtrak workers are threatening to strike as early as January 30, following a 30-day cooling-off period.

When Amtrak was threatened with a similar strike in 1997, union officials agreed to let several dozen workers cross the picket line to keep operations going at Penn Station, where the heavily subsidized railroad company controls the tracks. The strike was eventually averted.

The unions are demanding higher wages through retroactive pay for the eight years they have worked without a new contract.

Last week, an emergency board appointed by President Bush recommended that Amtrak meet the unions’ demands.

The Office of Emergency Management is preparing contingency plans to accommodate commuters in the event that the strike does take place.

If a settlement is not reached by the end of this month, it will be the first strike in Amtrak’s 36-year history.