Contract talks resumed Tuesday between the Metropolitan Transportation Authority and Long Island Rail Road unions, but the two sides could not come to an agreement.
Railroad workers are threatening to walk off the job at midnight on July 20 if a deal isn't reached.
They've been working without a contract since 2010.
A walkout would affect more than 300,000 daily riders.
The MTA is turning to Congress for help, with Chairman Thomas Prendergast set to meet with lawmakers.
"Since the unions don't seem to be willing to negotiate a settlement at the table here, the only people who have the authority to step in and prevent a strike from paralyzing Long Island are the ones in Congress," said MTA spokesperson Adam Lisberg.
The union leaders said they're ready to deal, even after rejecting the MTA's latest offer for 17 percent pay raises spread across seven years.
"Let's get this deal done. Let's not look to Congress. Let's not look to anybody but the both parties on both sides to negotiate this settlement, now," said Anthony Simon, general chairman of the United Transportation Union.
"They're playing Russian Roulette with the public. We need to stop this. There's a deal to be had. Let's have it."
Strike contingency plans could include asking LIRR riders to work from home, moving them on shuttle buses, setting up Park and Ride lots at locations such as Aqueduct and Citi Field, or having them crowd onto the subway.