Photo of an interlocking by railsr4me on Flickr.

On Thursday, the Maryland Transit Administration informed MARC riders of its plans to spend $18.5 million to add three rail crossovers to the CSX tracks the Brunswick Line runs on.

These interlockings will increase track capacity by enabling CSX train dispatchers to weave faster trains around slower trains. And it will improve reliability by allowing operating trains to go around disabled trains.

In the roughly 35 miles between the Silver Spring and Point of Rocks MARC stations, there are currently three places where trains can cross from one track to the other. These interlockings are at Georgetown Junction (between Silver Spring and Kensington), Derwood (near the Shady Grove Transfer Station), and Buck Lodge (between Boyds and Barnesville). The distance between the interlockings is 10-12 miles.

The MTA plans to add a crossover at Randolph Road (near White Flint) in 2011. In 2012, they will add another interlocking at Clopper’s, between Metropolitan Grove and Germantown, and complete an interlocking at the Pepco power plant in Dickerson. This will reduce the distance between interlockings to 5-7 miles.

Jim Knighton, Director of the MTA’s Office of External Affairs, says that roughly one-third of the money will come from the federal government, through the American Recovery and Reinvestment Act of 2009. The remaining $12 million or so will come from the Maryland Transportation Trust Fund.

According to the MTA’s TIGER grant application from September 2009, the MTA sees the additional interlockings as an intermediate step towards the capacity the 2007 MARC Growth and Investment Plan envisions by 2035 through adding a third track.

Right now, Brunswick Line MARC trains typically run in one direction on one track, while freight trains run in both directions on the other track. For MARC riders, more interlockings will mean fewer delays due to engine breakdowns, signal failures, or track work, because of CSX dispatchers’ improved ability to send operating trains around the problem.

More crossovers will also mean fewer delays for MARC trains due to “freight congestion”. The new interlockings will increase the effective capacity of the tracks by allowing CSX dispatchers to move faster trains around slower trains, rather than simply segregating freight and passenger trains by track.

Of course, CSX will benefit too. With the increased track capacity, there will also be fewer delays for CSX trains due to freight congestion. And, because stop-and-go commuter trains can be slower than freight trains, there will be fewer delays due to what might be described as “passenger congestion”.

So why is only the MTA paying for the improvements?

The answer is certainly not because the MTA has lots of extra money. The Maryland Transportation Trust Fund is down 13% since 2007.

CSX, on the other hand, reports a net profit of $414 million (up 43%), an operating profit of $825 million (up 39%), and revenue of $2.7 billion (up 16%), in the third quarter alone.

The answer is rather that, as the MTA’s TIGER grant application explains, “The work identified in these projects is driven by the need for greater reliability and frequency in commuter trains. CSX, on its own, would not have initiated this work.”

This also happens to be one of the major points in James McCommons’s excellent and enlightening Waiting on a Train: The Embattled Future of Passenger Rail Service, a book that explores the current sorry state of American passenger trains and suggests how trains might once again become a real transportation option.

According to McCommons, the major railroads, including CSX, are not opposed to passenger trains on their tracks, as long as the tracks have enough capacity to handle both their own freight trains and the passenger trains. But if capacity is insufficient, it’s up to the public agencies that operate the passenger trains to invest the money to fix the problem.

Needless to say, these public agencies have generally not had the money to invest. The MTA’s announcement therefore demonstrates Governor O’Malley’s continuing support for MARC — especially when compared to his predecessor, former Governor Ehrlich.

Over the past month, Brunswick Line riders have had reason enough to despair. With this announcement, they now have reason to hope, as well.