Senator Charles Schumer wants federal authorities to look into how hot weather might be affecting New York's rail systems.
Schumer cited Thursday's freight train derailment in the Bronx in which 10 cars went off the tracks.
Metropolitan Transportation Authority officials say they are still investigating the cause, but it may have been related to the heat.
It led to the suspension of service on Metro-North's Hudson Line between Grand Central and Yonkers.
Schumer says that incident and several other recent breakdowns are costing commuters time and money.
"There's no question the climate's getting warmer, and the heat-related incidents are increasing. We shouldn't just twiddle our thumbs, especially in a place like New York. Enough is enough," said Schumer. "The federal government has the resources to both find out what went wrong, and provide the dollars to make sure it doesn't happen again."
Schumer says he wants the government to look into how much it would cost to make heat protection upgrades on rail systems.
Meanwhile, the MTA says crews have been working around the clock to clear wreckage and debris from the derailment that occurred last Thursday near 225th Street in the Bronx.
More than 1,500 feet of track needed to be rebuilt, but the agency says the Hudson Line should return, in part, for the Monday morning rush.
The agency is telling commuters to anticipate delays, especially northbound passengers.
For now, people heading north out of the city can take the 1 train to 242nd Street near Van Cortlandt Park, where buses will connect to Yonkers to continue upstate.
Southbound trains terminate at Yonkers, and buses will bring riders back to the subway.
Hudson Line tickets are also being cross honored on the Harlem Line.
For the latest updates, visit mta.info.