New BART Train Inside

Source

@SFBART via Twitter

BART's new trains have experienced delays, leading many to question when they would finally run. But finally, the new trains are starting to run in regular service. At a time when capital projects in the United States cost a multiple of their peers in the rest of the developed world, the BART train order deserves recognition for its cost control.

The order consists of 775 cars, manufactured by Canadian firm Bombardier, costing $1.5 billion in total. Although the anonymous transit blogger Drunk Engineer criticized the order for costing nearly $2 million per car, it’s important to remember that BART cars are relatively long, at 70 feet per car. Most metro systems have shorter cars: New York's trains are mostly 60 feet, Paris's are 50 feet, and London's are 51 to 57 feet. However, regional trains tend to have longer cars: the American standard is 85 feet, and some European trains (including the KISS, to be used on Caltrain after electrification) are this length, while others have 60-foot cars.

Costs around the world seem to scale with length. For a 70-foot car, just under $2 million is exactly how much one should expect based on global procurement costs, such as those of Singapore, London, Manila, and Paris. High-performance single-level regional trains in Germany cost about the same per unit length as well.

The trains themselves are fairly conservative. For example, they do not have open gangways, allowing people to move between cars seamlessly. American transit agencies are resistant to the idea, and recently only one city, New York, decided to order trains with open gangways. Open gangways would have provided extra capacity by letting people ride between cars and move within the train from more-crowded to less-crowded cars. 

However, in one way the trains are a major improvement over the old trains: they have three pairs of doors per side, rather than two. BART is unique among subway systems in that it has long cars with only two pairs of doors per side, which makes it harder for passengers to get on and off trains at rush hour.

During peak morning hours, Embarcadero and Montgomery Street stations have a rush of passengers trying to leave the trains to go to their offices in the Financial District, and with only two doors open per car, this takes longer than it should. The time the doors stay open, called “dwell time,” impacts both speed and capacity: speed, because if the train's doors are open, it isn’t moving; and capacity, because the dwell time has to be added to the train's stopping time to determine the minimum headway between two successive trains. This affects train frequency throughout the station.

BART's peak capacity today is 24 trains per hour: four trains per hour on each of the four branches feeding the Transbay Tube, and eight additional peak-only trains coming from Concord. This short of the Tube’s maximum physical capacity, which, given BART’s many branches, is realistically about 27 trains per hour.. Unfortunately, the long dwell times at Embarcadero and Montgomery Street make it more difficult to run trains as closely together as they otherwise could.

With three doors open per car rather than two, passengers could disembark at a rate 50% faster than they can today, alleviating the crunch. This should allow BART to squeeze a few extra rush hour trains through the Tube, reducing peak crowding levels.

The fact that the new BART trains are not unusually expensive has some implications for future investment. New tunnels are prohibitively expensive, and so far, plans for them leave much to be desired. However, new rolling train stock is not. This suggests that BART should aim at demanding more of its trains: in future orders, this means even more doors and open gangways, in an attempt to maximize train capacity on existing lines.

The system’s first major improvement since its opening forty years ago promises better days ahead—and thankfully, BART won’t have to reinvent the wheel to improve everyone’s commute.

Alon Levy is a mathematician with a strong interest in urbanism and mass transit, and currently works as a freelance writer. He contributes to the Bay City Beacon as a weekly transit columnist for Pedestrian Observations. You can find more of his writing supporting walkability and good transit.

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