A computer system that allows speeding trains to be slowed remotely – potentially averting deadly derailments – was installed in the section of track in Philadelphia where Tuesday’s fatal Amtrak crash occurred but had not been turned on, congressional sources tell U.S. News.

“The PTC was installed in the section of track where the Philadelphia accident occurred, but for whatever reason had not been turned on, the PTC in that section,” Rep. Charlie Dent, R-Pa., tells U.S. News, referring to "positive train control."

His account was corroborated by Rep. Andy Harris, R-Md.

“The tracks had PTC, the train had PTC,” Harris says.

Both congressmen are members of the House Appropriations Committee, which contacted Amtrak for more information about the crash.

The train, Amtrak Northeast Regional 188 from the nation's capital to New York City, was hurtling at more than twice the recommended speed limit when it jumped the tracks just after 9 p.m. Yet the technology that could have slowed it had not been enabled – allegedly because of delays in installing the system, Harris, Dent and a third congressional source say, citing communications between the Appropriations Committee and Amtrak.

"According to Amtrak, PTC was installed in the section of track where the Philly accident occurred," a committee source writes in an email to U.S. News. "There have been delays in 'turning it on' associated with FCC dealings and getting the bandwidth to upgrade the radios from 900 MHz to something higher (for more reliability)."

Amtrak's application for the bandwidth needed to use the positive train control system was approved in "early March," an FCC official says.

“The spectrum Amtrak wanted to use in 2011 was owned by someone else," the official says. "It took them three more years to negotiate with private parties to acquire the needed spectrum for the Washington, D.C.-to-New York corridor. Once Amtrak finalized their application, the commission approved it within two days.”

Amtrak President Joseph Boardman said Thursday the technology was installed where the crash occurred, according to The Associated Press, but it had not been turned on because the system needed to be tested further.

Positive train control uses radio and GPS signals as well as other technologies to detect and reduce trains' speed. Congress demanded the technology be implemented nationwide by 2015 after a California train collision left 25 people dead and more than 100 injured in 2008.

Federal officials investigating the crash said that had the system been in place, the incident could have been averted.

“We feel that had such a system been installed in this section of track, this accident would not have occurred,” National Transportation Safety Board member Robert Sumwalt told reporters during a news conference Wednesday.

Eight people died and more than 200 were injured in the incident. The train was speeding at 106 mph – more than twice the speed limit of the curve where it derailed.

Amtrak and the National Transportation Safety Board did not immediately return calls and emails seeking comment Thursday evening.

The crash has sparked intense debate on Capitol Hill over Amtrak funding, with Democratic lawmakers lambasting Republicans on the House Appropriations Committee for approving a bill Wednesday – just hours after the crash – that would reduce Amtrak funding by about $260 million.

“It is simply a fact that insufficient funding for Amtrak has delayed the installation of PTC, and to deny a connection between the accident and underfunding Amtrak is to deny reality,” said Sen. Charles Schumer, D-N.Y., who called claims to the contrary "patently false."

House Speaker John Boehner, R-Ohio, speaking earlier in the day, lashed out at Democrats' critiques.