Last week, we took a look at Amtrak's $151 billion proposal to convert the heavily trafficked Northeast Corridor into true high-speed rail. Under this vision, the Acela train would no longer average a plodding 70 mph across the system. A trip from New York to Washington, D.C., would take just 94 minutes instead of three hours. Boston to D.C. would take just three hours instead of seven.

Rendering of Amtrak's proposed high-speed train. (Amtrak)

The catch, as always, is that the $151 billion plan is expensive. When the high-speed line is complete, Amtrak would generate an operating surplus of about $1.65 billion per year. That's a nice jar of change, but it's not enough to finance the upgrade of the rail line. Which means Amtrak would need help from Congress. And while $151 billion spread out over 28 years is a pittance compared with, say, what the war in Iraq cost, the Republican-controlled House doesn't appear to be in the mood to fund vast new rail infrastructure projects right now.

So are there cheaper options? Quite possibly. Over at Pedestrian Observations, transportation analyst Alon Levy takes a critical look at Amtrak's high-speed plan. A great deal of the cost, he notes, comes from Amtrak's proposal for deep underground tunneling in New York City and Philadelphia. As a more modest alternative, Levy argues, there are a whole bunch of smaller incremental steps that Amtrak could take to significantly improve service between D.C. and Boston for a fraction of the cost.

To take just one single example, upgrading Amtrak's trains — for a cost of about $2 billion — would begin to chip away at travel times. "The difference between an average and a top-rate train could easily amount to 20 minutes between Washington and Boston," writes Levy. Obviously, 20 minutes isn't much, but we're just getting started. Levy also points out several places where upgrading the curves on existing tracks or improving platforms could allow Amtrak's trains to achieve faster speeds. All of these measures start to add up.

Another money-saving strategy, Levy notes, would be for Amtrak to coordinate with local commuter lines to share tracks, rather than building entirely separate tracks. "This requires fixing agency turf battles, which costs a lot of political capital but is almost free to the taxpayer," Levy writes. "Amtrak’s single biggest question mark east of New York is the string of tunnels from Penn Station to New Rochelle to Danbury, all so that it doesn't have to share tracks with Metro-North." (Here's New York MTA head Joe Lhota making a similar plea for harmony among rail agencies.)

There are a bunch of other suggestions in his post, which is worth reading in full. By combining a bunch of these smaller measures, Levy estimates, Amtrak could potentially whittle the Boston to D.C. trip down to four hours at a fraction of the cost. That, in turn, could help the company generate the profits needed for true high-speed investment down the way — particularly if Amtrak purchases bigger trains that can seat more passengers.

Meanwhile, in the New York Daily News, Josh Barro makes some similar suggestions for tweaks to nudge Amtrak closer to high-speed rail: "Upgrading the power system between New York and Washington would allow Acela trains to run at 150 miles per hour instead of the current 135, and will allow future trains to go even faster. Extending station platforms would make it possible to run longer trains that seat more people. Targeted additions of rail mileage — including an additional tunnel under the Hudson River — are needed at some choke points."

In any case, it will take a more in-depth analysis to look at all these different options and figure out which ones are the most effective. Perhaps, when all the numbers are crunched and benefits analyzed, it will turn out that Amtrak's full-blown $151 billion vision is still the way to go. But both pieces are a reminder that even modest upgrades to our rail infrastructure can have a major impact.