In the public eye, the disaster on the rails this week in Philadelphia was not only tragic but also shocking. As a crowded Amtrak train approached a bend in the track on Tuesday night, it was barrelling along at more than 100 miles an hour -- twice the mandated speed for that section. The resulting derailment killed eight people, highlighting grave deficiencies in Amtrak’s safety system.

But while Amtrak officials may have been devastated, they could not have been shocked: The accident confirmed clear vulnerabilities in the safety system, shortcomings that the rail company’s internal watchdog had been warning about for more than two years.

In a December 2012 report, Amtrak’s inspector general wrote that “formidable” and “significant challenges” were delaying deployment of a safety system known as Positive Train Control (PTC), which identifies cars that are traveling at excessive speeds and automatically slows their progress. Four years earlier, Congress had required that Amtrak and other American rail companies add the technology to their operations, but only a fraction of the rail systems were by then covered. Had the PTC technology been in place in Philadelphia, federal regulators say, this week’s derailment might well have been prevented.

The inspector general’s 2012 report zeroed in on one missing element that was crucial to the broader deployment of the safety system: Amtrak had for years failed to acquire adequate rights to broadcast communications signals through the public airwaves. Without these so-called spectrum rights, Amtrak’s trains could not communicate with the electronic brains of the safety system, preventing its use along key stretches of track. This lack of spectrum had become the “most serious challenge” in the railroad’s efforts to deploy the safety equipment more broadly, Amtrak’s watchdog warned.

Why that technology was not operating at that bend in the track in Philadelphia and along much of Amtrak’s system is in part a story of repeated cuts to the company’s budget by its ultimate overseer, Congress. It is also a product of the complex challenges of adding modern wireless communications gear to an industrial-era railroad system that sometimes seems more closely tied to the age of the steam engine than the digital age. But it is also a saga of lethal consequences flowing from bureaucratic friction between two arms of the government with different modes of operation: Amtrak and the Federal Communications Commission.

Officials at the FCC, who declined requests for on-record interviews, said the agency was not the holdup in Amtrak’s pursuit of wireless spectrum. Amtrak did not respond to questions.

Amtrak is well-accustomed to criticism, having been frequently lampooned for a range of perceived shortcomings, from budget overruns and poor on-time performance to unappetizing menu items and atrocious customer service. But the recurring element in the story of Amtrak’s failed efforts to fully install critical safety technology is wireless spectrum: the finite number of invisible radio-wave frequencies able to transmit bits of data -- the kind of data that a PTC system requires to track a train and automatically reduce its speed when it is traveling too fast.

In seeking to acquire spectrum, Amtrak has found itself wading into a realm dominated by enormous, deep-pocketed and savvy companies, from Google to Verizon to AT&T. As the Web has steadily expanded beyond its former desktop confines to mobile devices such as smartphones and tablet computers, and as growing numbers of Americans have come to rely on wireless links to access video entertainment and work emails, demand for spectrum has grown exponentially.

The Federal Communications Commission functions as the air traffic control system for the public airwaves. It distributes rights to broadcast over dedicated slices of spectrum while seeking to avoid interference, and constantly answering to intensifying claims for more.

As Amtrak officials have set about acquiring spectrum rights, they have long maintained that their safety system requires an exclusive frequency to transmit such data, one that does not have to compete with -- or face interference from -- other transmissions like radio, television or cell phone signals. But when Congress in 2008 mandated that rail companies like Amtrak install PTC on their tracks, lawmakers did not require the FCC to set aside any of those airwaves for this exclusive function.

Flush with profits, private railroad firms responded to the mandate by quickly obtaining their own licenses in the 220Mhz frequency range. That spectrum was particularly useful for communications across long distances, making it appropriate for long-haul freight carriers passing through rural areas. With that in mind, a consortium of private rail operators began purchasing blocks of spectrum in that frequency in 2007 -- both in anticipation that they would need it themselves, and also as a potentially sound investment: As Congress required the deployment of PTC the following year, and as the private rail operators pushed to make 220 mhz the accepted standard for those systems, the value of spectrum rights in that band climbed.

Faced with competition, budget-strapped Amtrak repeatedly failed to secure its own deals to the airwaves, stymying its efforts to install the PTC technology on its passenger rail service. This gap was especially troubling in the Northeast Corridor running from Washington to Boston, Amtrak’s most congested and most profitable area of operation. Congress did not step in to to set aside spectrum for this purpose, despite warnings from Amtrak and other public transportation officials.

“Railroad representatives said that obtaining spectrum is a critical challenge in high-density urban areas,” the General Accountability Office, the independent agency that audits federal agencies, concluded in an August 2013 report. “Without acquiring sufficient spectrum, railroads may be unable to adequately test their PTC systems, potentially causing further delays.”

Lacking deals to buy spectrum, Amtrak executives and other public transportation officials began calling on the FCC to provide access to unused bands of spectrum in the 220Mhz frequency. Had the rail lines sought other spectrum, their safety system operations would not have been compatible with the private firms that were already operating on that frequency, they argued.

But the FCC declined their requests, telling Amtrak that it did not have legal authority to bequeath spectrum, while insisting that the rail operator could find licenses in the 220Mhz band on the private market.

Some technology experts say the FCC was right to reject Amtrak’s demands while accusing Amtrak of making a critical error in the design of its PTC system: Its scheme was reliant on its gaining access to one dedicated slice of spectrum in an effort to avoid interference with other users of the airwaves. That put the company in the position of having to then acquire exclusive rights -- this, in the midst of the explosion of smartphones and wired “smart grid” energy facilities, which generated unprecedented demand for the right to transmit signals through the skies.

According to telecommunications policy experts who spoke to the International Business Times, Amtrak’s design was both unnecessarily inflexible and outmoded: Advances in telecommunications have yielded new ways of transmitting signals that allow different users to share the same slices of spectrum without encountering interference. Smartphones, as an example, can often transmit and receive information across different spectrum. Researchers in the United States and overseas have also been promoting rail safety systems that rely on standard commercial or shared spectrum. Had Amtrak embraced such a system, it could have much more easily acquired the spectrum rights needed to make it functional.

“People are operating with assumptions which were perhaps true in an analog world, but in a digital space with these new found things called computers, you do not need a standalone piece of spectrum for mission-critical operations,” said Sascha Meinrath of X-Lab, a technology focused think tank. “It is in fact potentially far less reliable to have one standalone national network on one piece of spectrum than to have multiple redundant networks operating on common or commercial spectrum.”

Hours after the Philadelphia derailment, another technology expert, Harold Feld, wrote on his Facebook page that Amtrak could have used already-laid telecommunications cable and widely available non-exclusive spectrum -- like the unregulated frequencies used for household wifi -- to bring online a PTC system well before the disaster.

“We have boatloads of fiber running alongside train tracks in the rights of way,” wrote Feld, a senior vice president of the think tank Public Knowledge. “If I were architecting this system, I could deploy it tomorrow using unlicensed spectrum.” Amtrak’s “obsession with exclusive licensing kills,” he concluded.

Some industry sources dispute such accounts, arguing that the life-and-death nature of the PTC system requires that it operate on its own dedicated channel to prevent any possibility of interruption.

“You have to have spectrum that is specifically dedicated to this function,” said Karl Witbeck, a PTC expert at Stantec Consulting. “The idea here is that this is a public safety critical system and you don’t want anybody else interfering with it.”

Another engineer who works with the freight industry’s separate PTC system put it this way: “If you were using public cell phone signals as the PTC signal and it’s Mothers Day and everyone is calling grandma, then it could jam up the cell network that the trains are relying on for their safety system.”

Amtrak itself promoted that view in 2011, as railway officials sought a waiver from the Federal Communications Commission to help acquire licenses for exclusive spectrum. In their FCC filings, Amtrak executives declared that a “consensus of opinion that has emerged” in the train industry around PTC relying on a dedicated 200Mhz frequency.

Whatever the technical merits of that argument, the rail industry’s consensus that the 220 mhz band was best for the new safety technology created a veritable land grab for licenses on that slice of the airwaves. A consortium of private rail operators wound up with many of the licenses.

By 2010 -- only two years after Congress required the roll-out of PTC systems -- Amtrak and other publicly own commuter transit systems were already complaining that they could not secure the spectrum.

Some of their difficulty was financial, the result of Congressional budget cuts. In a letter sent to FCC officials in June 2010, Joseph Szabo, head of the Federal Railroad Administration, which regulates the nation’s rail system, blamed revenue pressure for the industry’s failure to gain spectrum rights. He urged the FCC to give public transit systems available spectrum rather than following normal procedure and auctioning off the rights -- a process that left Amtrak at a distinct disadvantage alongside better-capitalized entrants.

“[Commuter railroads] are specifically operated to provide a public service, as opposed to private gain, they rely heavily on public funding to meet operating and capital requirements,” Szabo wrote. “The financial ability of such railroads to obtain the necessary spectrum to meet the statutory deadline is questionable at best."

That same month, Amtrak appeared on the verge of gaining the rights to spectrum in a deal with a telecommunications firm. But the seller soon found itself on the wrong end of a lawsuit challenging its right to the licenses. The deal fell through.

By 2011, rail companies and the Federal Communications Commission were blaming one another for continued delays in rolling out the Positive Train Control system.

At a congressional hearing early that year, a regional transit official from South Florida accused the FCC of holding up two applications for spectrum from local transit agencies. He urged lawmakers to back legislation forcing federal regulators “to act now to reserve and reallocate spectrum” to passenger rail carriers in major cities.

That same year, Amtrak sought to lease spectrum from private freight companies, but the firms ultimately refused to hand over the rights, citing worries about technical complications.

When Amtrak executives met with FCC officials urging them to hand over spectrum in the 220Mhz range, the private companies that owned licenses in that range complained. They had paid  "the U.S. Treasury millions of dollars for these licenses and have invested millions more in equipment acquisition, facilities construction and system operations," these license holders argued in a filing with the FCC.

In October 2011, Amtrak explored another deal to buy spectrum along the Northeast corridor, but officials ultimately concluded that the proposal did not offer them enough bandwidth for the PTC system.

In 2012, Amtrak pressed the late New Jersey Sen. Frank Lautenberg, a Democrat, to pressure the FCC to hand over the needed spectrum. Amtrak officials also met with staff members of the Senate Commerce Committee to discuss this approach.

At about the same time, X-Lab’s Sascha Meinrath met with officials the National Transportation Safety Board. In emails to those officials, he warned that the plan to try to create a PTC system dependent on one exclusive frequency is “the height of foolishness.” He push the regulators to consider instead “building a multi-band system capable of riding over existing infrastructure,” meaning one that could operate across a wide band of spectrum.  Meinrath says he never heard back.

Last year, as a congressionally mandated deadline for full PTC implementation drew near with Amtrak’s Northeast Corridor still not fully covered by the safety system, the trade association representing transit agencies called on lawmakers to adopt legislation forcing the FCC to give public rail systems exclusive spectrum. Congress was awash in campaign cash from spectrum-hungry telecommunications companies. No bill emerged.

Only this year, on March 4, did Amtrak secure FCC approval for a deal with a private license-holder called Environmentel LLC. Amtrak said the deal finally put it in position to complete the PTC system all along on the Northeast Corridor.

“It's everything they need and portions of the Northeast corridor that they did not have,” Environmentel president Warren Havens told IBTimes. “The tragedy is that it’s years behind in getting the spectrum it needed to complete its positive train control system.”

One FCC official noted the commission took only two days to approve Amtrak’s proposed deal with Havens’ firm, once the paperwork was submitted to the commission. At a briefing in Washington on Tuesday, FCC Chairman Tom Wheeler -- who formerly headed a major wireless industry trade association -- said his agency had been “making some real serious progress on PTC.”

But it didn’t come fast enough. Hours after Wheeler’s comments, the train in North Philadelphia derailed on a stretch of track that still did not have the system up and operational.

Telecommunications policy experts cautioned against blaming federal regulators for the delays that slowed the installation of the safety system.

“The FCC was totally right on this,” said Feld, the technology expert.

A longtime telecommunications policy expert, Andrew Jay Schwartzman, a lecturer at Georgetown University Law School, said the FCC’s job requires making difficult decisions amid competing claims for spectrum. In this case, the agency was cognizant that the same frequency Amtrak sought for its communications is also used by public utilities.

“Obviously in the benefit of short term hindsight, PTC is a very important goal, but so is not having the electrical grid break down,” Schwartzman said. “It’s just not so simple as well we decided this is the spectrum that would work for us and we want it and went to the FCC and they just won’t give it to us. It’s never that simple.”