Cameron Beach Grills MTA Staff on Slow Speeds in Twin Peaks Tunnel

West Portal station, at the western end of the Twin Peaks tunnel. Flickr photo: Matt Roe

MTA Director Cameron Beach expressed his frustration today about slowed Muni vehicles that have nothing to do with traffic congestion or frequent bus stops: for almost as long as he's been a director, Beach complained, trains in the Twin Peaks tunnel between Castro and West Portal stations have been operating well below their historical speed of 50 miles per hour.

During a major rehabilitation of the overhead wires in the 2.27-mile tunnel in 2006, the MTA discovered that the tracks in the tunnel were in such poor shape that trains traveling at their usual top speeds were in increased danger of derailment. A track rehabilitation program early last year was intended to fix the problem, but trains are still running at slower speeds as the MTA works to certify that the tracks are safe.

At an MTA Board committee meeting today, Beach asked for an update on when trains will start passing through the tunnel at higher speeds again.

The track rehabilitation "never did raise them, that's the issue," said Beach, who rides through the tunnel frequently to get downtown. "It's been almost three years now since we've had 50 mile per hour operation in that tunnel."

That prompted an update from MTA Executive Director Nat Ford, who summarized the history of the "slow speed order" in the tunnel, but wasn't able to present a timeline for raising the speeds.

"There's been some debate about what is normal speed in the tunnel," said Ford. "There was the historic speed, and the degradation of the track that forced a number of slow speeds in sections. Then the work that we did about two or three years ago to resolve that issue, and the track geometry work that was done to help certify the speed in that tunnel."

The MTA's Safety and Operations divisions are still working to certify that the tracks are suitable for higher speeds again, Ford told Beach. Speeds were set for several different segments of the tunnel, and some speeds were brought up incrementally, but trains still operate at much less than their one-time top speed of 50 miles per hour, explained MTA Director of Capital Programs Carter Rohan.

Trains currently travel through most of the tunnel at 35 miles per hour. For a short stretch between Castro station and a segment of the tunnel known as the Eureka curve, vehicles are limited to 20 miles per hour. Today, it takes about seven minutes to travel through the tunnel without any congestion from other light rail vehicles, though much longer waits are not uncommon as vehicles bunch up near West Portal station.

Potential congestion at West Portal could negate some of the benefits of higher speeds in the tunnel, said Ford. "If we did go up to the maximum speed that was somewhere in history on that track, do we end up creating a logjam at West Portal going outbound because the trains would be speeding up and catching up with each other?"

That question and safety concerns are still being worked out by MTA engineers, said David Hill, the MTA's interim director of transit. The MTA has had two consultants look at the issue, and is reviewing the information the consultants provided them. A derailment in the tunnel last month has been a further setback, but Hill said his staff is still working to determine whether trains will ever be safe to travel at higher speeds again. "After we're complete with our analysis, and the analysis from the consultants, then we'll be coming back to meet with Mr. Ford to make a determination at that time."

Beach was clearly not entirely satisfied with the response.

"What I'm hearing now is there are a number of studies being analyzed with no target for an answer or closure on the issue. To say that I'm frustrated with that is an understatement," said Beach. "I would like staff to come back not only to this committee but the full board with a comprehensive report on where you're at and a schedule of finishing this task."

Beach will get his wish - for a schedule, if not for faster speeds - at the January 12 meeting of the MTA Board's Policy and Governance Committee.

"We'll get to the bottom of this and get this resolved," said Ford.