New York's top mass transit official headed to Washington on Wednesday to urge Congress to block a threatened strike on the Long Island Rail Road, the nation's largest commuter railway.

The plea by Metropolitan Transit Authority Chief Executive Officer Thomas Prendergast came as a 60-day cooling-off period winds down, allowing 5,400 workers for the Long Island Rail Road to walk off the job on July 20, stranding 300,000 daily commuters.

"I will be traveling to Washington D.C. to meet with members of Congress on the MTA’s position and request a clear answer on whether the United States Congress is prepared to take action if LIRR’s unions decide to stage a strike," Prendergast said in a letter sent on Tuesday to House of Representatives Speaker John Boehner.

Congress has several options to address the possible strike.

It could allow the strike to proceed and then pass a resolution ending it and implement a settlement, or require mediation or arbitration. Congress could also vote to extend the cooling-off period or it could also do nothing.

Prendergast planned to give an update on his congressional meetings later on Wednesday, the MTA said in a statement.

In addition to the meetings, the MTA launched a communications blitz on Wednesday to alert riders of possible service disruptions caused by the strike.

Through newspaper ads and its website, the MTA told LIRR passengers to plan to work from home during the strike or carpool. There also would be a limited number of MTA buses available, although they would not be able to accommodate all of LIRR's daily riders.

"Expect roadways to be extremely congested and usual commute times to be significantly longer," the MTA said.

The MTA and a coalition of eight unions representing LIRR workers have unsuccessfully negotiated for four years on labor contracts and have worked with federal mediators to reach a deal.

In their latest proposals, the MTA offered a 17 percent wage increase to union workers over seven years with higher contributions for medical insurance and pensions made by future employees, both sides said. The unions have asked for a wage hike of 17 percent over six years without concessions for future employees.

The wage increases would be applied retroactively through 2010.

The union coalition was not immediately available for comment on Wednesday.