Single tracking, mid-line transfer for 10 weeks in 2020

Before East Link comes online in 2023, the extension's track has to be connected to the existing light rail network just south of the Chinatown/International District (CID) station. Sound Transit will close existing portions of both north and southbound track for 10 weeks in early 2020 to make the connection, according to plans released yesterday.

Service will continue during construction, with the exception of three total closures during one weekend each in January, February, and March, but it will not be fun.

"We had two options: close the line for several weeks during construction, or continue to serve our 80,000 daily riders over a slightly longer construction period. We choose to keep service running at the highest level conditions will allow," Sound Transit CEO Peter Rogoff said in a release.

Riders will have to keep that in mind during the transit version of Viadoom that will dominate the first quarter of 2020. According to Sound Transit officials, the ubiquitous, behavior-changing messaging that made the Carpocalypse bearable was the reason for getting the word out a full year in advance.

I describe how the single tracking will work below (as has STB alum Zach Shaner), but this animated diagram released by Sound Transit does the best job explaining how trains will run.

Here's how service will change during the 10 week closure:

• To ride the whole line from end to end, passengers will need to change trains at Pioneer Square station on a purpose-built center platform.

During Phase One, trains bound north from Angle Lake will:

• Traverse switches at the Sodo station to a terminus at Pioneer Square station, running on the normally southbound track between CID and Pioneer Square.
• At Pioneer Square, all train doors will open.
• Passengers will disembark onto the center platform and onto a waiting train to continue north, or exit the station on the normal platform.
• The train operator will switch ends and, on the return trip to Angle Lake, travel south on southbound track like normal.

Something of a reversal will happen in the opposite direction. Trains bound south from Husky Stadium will:

• Traverse a switch at Westlake station to travel on normally northbound track between Westlake and Pioneer Square.
• At Pioneer Square, all train doors will open.
• Passengers will disembark onto the center platform and onto a waiting train to continue south, or exit the station on the normal platform.
• The train operator will switch ends and, on the return trip to Husky Stadium, travel north on northbound track like normal.

During Phase Two, the rider experience will be very similar, but Husky Stadium trains inbound to Pioneer Square will run on normally southbound track, and reverse direction for outbound trips on the same. Angle Lake trains inbound to Pioneer Square will run on normally northbound track, and reverse direction for outbound trips on the same. Another animation:

This balletic operations plan will demand more than usual from train operators and the control center. Trains will run on 12 minute headways all day, including at peak. Every train will have four cars, including off peak.

Personnel on the center platform will use radios to ensure that no passengers are on the center platform when trains depart. Trains will be dispatched in such a way that both north- and southbound trains will arrive simultaneously at Pioneer Square. Simultaneous arrivals are the main driver for the 12 minute headway.

Other Sound Transit staff will guide passengers through Pioneer Square station and answer questions during the single tracking.

During the full weekend closures, a special circulator bus line will fill in for Link service.

Sound Transit estimates that the headways and added capacity will square exactly with estimated peak demand, which will require moving about 3,000 people in the absolute busiest hour.

The agency chose this period for single tracking because they don't believe the Seahawks will make the playoffs the Seahawks season will be over, and the Mariners' season won't have started yet. It also comes before Northgate Link testing and non-revenue service start.

At the Operations Committee meeting where agency officials presented the plan, Sound Transit board members Rob Johnson and Joe McDermott encouraged the agency to consider special events in scheduling the weekend closures. Johnson singled out seasonal events like the Lunar New Year, which always draws extra visitors to the CID.