San Francisco’s Muni light-rail offers a convenient ride to most of the city, but it hasn’t kept up with the times. Fixing it will be no easy task. 


Muni Metro offers fast public transportation from the Embarcadero to points south and west. West Portal, near the southwestern end of the city, has a train every 3-4 minutes, taking just 17 minutes to reach Embarcadero. And yet, it is far from a world-class system. It has severe capacity limitations: as a result, trains are full at rush hour, even as ridership is just 130,000 per weekday. The busiest two-track subway lines in the world have more than a million weekday riders. Muni’s limited capacity is due to outdated, unreliable equipment, but it is getting new trains, which will resolve some of the problems.


Muni Metro's subway-surface layout allows for higher capacity in the tunnel, where there is the greatest need for it. The surface segments, which have to obey traffic signals, are not just slower but also have less capacity. In this respect, Muni Metro is no different from other subway-surface lines around the world, such as the Green Line in Boston, the Subway-Surface Lines in Philadelphia, and the light rail ("Stadtbahn") in Cologne and Frankfurt.


Today, Muni Metro runs 36 trains per hour at the peak, across all five lines: the J, KT, L, M, and N. It can do this while BART struggles with just 24 trains per hour, because the trains are shorter and slower. Precisely because the trains are shorter, capacity measured in terms of passengers per hour is quite low.


Jamison Wieser, former member of the SFMTA advisory council, told the Beacon that the biggest capacity bottleneck today is at Embarcadero. The J, L, and M trains turn there, on a single pocket track, while the KT and N trains continue onward onto the Embarcadero itself and the new Third Street line. The next most urgent capacity problem is on the surface: the turn at 4th and King, where the KT and N share tracks in front of a busy freeway off-ramp, delays KT trains. The Central Subway will resolve it when it opens, by separating the K and T and routing the T away from the Market Street tunnel.


To add service without adding more trains than Embarcadero can handle, Muni can run longer trains. Here, the limit comes from a combination of past design decisions and poor rolling stock. When the Twin Peaks Tunnel was built, the stations were designed for 4-car trains in which each car was 68' long; the cars today are 75' long, and so the stations can only take 3-car trains. Therefore, current plans involve upgrades to 3-car trains, from the current mostly 2-car trains.


This is where new rolling stock comes in. The existing trains that Muni Metro uses are notoriously unreliable. The manufacturer, AnsaldoBreda, has a history of building poor equipment. Muni is instead ordering new trains from Siemens, of the same type that run successfully in Calgary. The Siemens order is very expensive: nearly $4 million per car. In France, Alstom produces Citadis light rail vehiclesfor about the same cost, but each vehicle is articulated, about 150' long, twice as long as Muni's Siemens cars.


But despite the high cost, the Siemens vehicles the city is buying have a good track record in Calgary. The plan is to replace 151 Breda cars with 260 Siemens cars, so that more Muni lines could run longer trains. Moreover, reliable equipment means fewer unexpected breakdowns. A larger proportion of the new vehicles will be available for peak service than of the current vehicles, which means that in practice, capacity measured in cars per hour will double.


San Francisco is planning to grow its housing and job numbers substantially in the next 20 years. By 2040, the state projects the city will have almost 1.1 million residents; the city's Transportation Demand Management plan assumes that in addition, it will add 190,000 jobs. Current development happens mostly in the inner core, but this amount of growth cannot happen exclusively in and near downtown. Muni Metro's underground segments provide fast service to the Inner Sunset, the Castro, and the areas around West Portal. Those neighborhoods could have more residents, if they had the rail capacity Muni is planning to provide with the new trains.

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