Earlier today, Barack Obama laid out his blueprint for spending $8 billion in stimulus money on high-speed passenger rail, flagging ten intercity corridors that could receive funds for new lines. The well-trafficked Northeast corridor is also eligible for upgrades, though, as Matt Yglesias's correspondent points out, most of the low-hanging fruit there has been plucked already, and it may be more effective to improve service elsewhere. Here's the White House's map of potential corridors (notice that much-maligned L.A.-Las Vegas route isn't eligible for federal funds).

Anyway, I was intrigued by a criticism Richard Nadler made over at the Corner. He notes that promoting passenger trains could actually increase greenhouse-gas emissions if they end up pushing freight off rail and onto trucks. At the moment, freight trains get priority in the United States, which explains why Amtrak is constantly plagued by delays—the passenger cars get short shrift. In Europe, by contrast, passengers get priority and freight gets shafted, which (Nadler argues) is why the EU ships far less of its freight by train, and hence has higher freight-related emissions.

Is this worth fretting about? We've seen before that one of the more sensible ways to save oil and curb U.S. greenhouse-gas emissions is to shift more freight off trucks and onto electrified rail. Granted, there's a decent case for bolstering the country's passenger-rail network, too, but if we absolutely had to pick one or the other, electrified freight rail does appear the better investment from an economic and climate perspective. So would a passenger-rail focus gum up those efforts? Actually, no, I'm not sure the trade-off is that stark.

Here's a useful paper by two economists, Jose Manuel Vassallo and Mark Fagan, exploring this question. In the 1950s, the portion of freight carried by rail was similar in the United States and Europe. But by 2000, 38 percent of U.S. freight went by train, compared with just 8 percent in Europe. Vasallo and Fagan argue that 80 percent of this disparity is due to geographical factors: Shipping distances are often shorter in Europe and sea transport is more competitive. That still leaves 20 percent of the difference due to other factors, including Europe's emphasis on passenger service and bad policies. For instance, Spain has long sported different track gauges than France, which means locomotives often had to be changed at the border, causing all sorts of delays and headaches. Lack of competition among carriers is another problem.

In any case, the paper argues that a robust passenger rail system and a decent rail freight system can co-exist, though striking a balance takes some effort. Schedules need to be optimized, new tracks may need to be built. Usually, when passenger trains reach speeds over 150 mph, they need their own right of way on flat tracks with gentle curves. (There's a reason Amtrak's Acela only hits its top speed once, for a very brief segment, during its jaunt across the Northeast—the tracks are unsuitable most of the way, and it has to share them.) Of course, these moves can require upfront investments and proper planning. Trade-offs do exist. But decent passenger rail and freight rail don't seem incompatible at all.

(Flickr photo credit: otisplodding)

--Bradford Plumer