The new system will warn engineers of the approaching speed reduction and can automatically enfore speed restrictions at four other curves.
On Monday morning, crews installed new signals at the curve in the Spuyten Duyvil section, the scene of the derailment.
Also Monday, the NTSB interviewed the engineer of another train that passed by just before the accident. That engineer says the derailed train did not dim its headlights as it passed, which is procedure.
Local lawmakers are also calling on train operators to install cameras to monitor the train's crew.
"I know you're going to hear from Metro-North that there are costs, but the costs of these audio and visual recorders is minuscule, in fact negligible, compared to the hundreds of millions of dollars that this tragic incident will cost Metro-North in the end," said Sen. Richard Blumenthal of Connecticut who joined New York Sen. Charles Schumer for a news conference at Manhattan's Grand Central Terminal.
Last Sunday, a Metro-North Railroad train approached a curve on the tracks just north of Manhattan going 82 mph - nearly three times 30 mph speed limit. Rail cars careened off the tracks, with the front car ending up inches from the water where the Hudson River meets the Harlem River.
A lawyer and union leader for the derailed train's engineer, William Rockefeller, have said the train's hypnotic motion may have caused him to experience a "nod" or a "daze" at the controls.
The Democratic lawmakers are urging the Federal Railroad Administration to demand the implementation of a measure they say might prevent the kind of deadly Metro-North derailment that also left dozens of people injured.
The National Transportation Safety Board first recommended installation of the audio and video recording cameras in locomotives and operating railway cabs five years ago.
The railroad administration issued a statement saying that safety was its "highest priority" and 2012 was the safest year in railroading history.
"We support the use of cameras in cabs to further improve safety," the agency said, adding that it continues to work with the NTSB on the investigation into the New York accident.
The NTSB said it has a "long history of advocating for improvements stemming from fatal accidents."
"In an era where the average citizen has a device in their pocket capable of recording audio and video, installing cameras in locomotives for accident investigation and prevention purposes simply moves the railroad industry into the 21st century," NTSB Chairman Deborah A.P. Hersman said in a statement.
Schumer said fatigue was suspected in two other collisions - one in Iowa, in 2011 and another in Newton, Mass., in 2008 - and might have been proven if cameras were present. He said such images might have caught behavior patterns that could have been prevented in the future.
"Get on board and implement these recommendations now," Schumer said, directing his comments to the Federal Railroad Administration, which has the power to demand the changes. The railroad administration has yet to take any regulatory action putting these recommendations in place.
"Shame on Metro-North for failing to adopt this system," Blumenthal said. "Shame on the operators of this railroad for failing to move forward with a recommendation that is so cost effective. Keep people alive."
The Metropolitan Transportation Authority, which runs Metro-North, released a statement late Sunday detailing immediate changes to improve safety on curves and bridges.
Those improvements include the installation of new signal safety protections at the crash site that - starting Monday - will warn engineers of approaching speed reductions and automatically apply the train's emergency brakes if speed is not lowered to the 30 mph maximum in the curve.
Metro-North engineers are also developing new signal protections to automatically enforce speed restrictions at four other critical curves by March and at five movable bridges by September, the MTA said.
By Tuesday morning, Metro-North will require that "conductors stand with engineers at each train's control cab through the critical curves to verbally confirm that speed limits are adhered to," the MTA said. The railroad will also reduce the maximum authorized speed at 26 locations.
The NTSB's recommendation for the camera program followed a train collision in California that killed 25 people, including the engineer, and injured more than 130. The NTSB said the engineer's texting was the primary cause of the accident.
In a letter this week to the NTSB, the two senators noted that "in the wake of a 2008 railway collision in California, the NTSB recommended inward facing cameras, which would monitor train crew performance, as well as outward facing cameras, which would be used to monitor crossing accidents and to recognize any deficiencies on the tracks."
Schumer and Blumenthal said they believe such recording devices "may be used as a deterrent for dangerous behavior, like falling asleep or texting, and may also be used after a rail crash to determine the cause of the crash."
Amtrak locomotives and California's Metrolink commuter rail have outward facing cameras that record signals and gate crossings.