Washington DC Metro Still On Manual Train Controls

Wary of Returning to Automated Safety System Control

2 min read
Washington DC Metro Still On Manual Train Controls

There was a story in the Washington Post yesterday on the continuing investigation into the June 22nd deadly collision of two Washington Metropolitan Area Transit Authority (Metro) subway trains. Since the crash, which killed 9 people and injured and additional 80, Metro train drivers have been ordered to operate their trains in manual mode, and the expectation is that it will be quite some time before they are allowed to operate under automatic train control mode again.

The crash investigation has centered on a circuit failure in the Metro systems automatic control system which did not detect a train's presence. The National Transportation Safety Board (NTSB) crash investigation found other circuit failures in the system, as well as revealed a little known incident in March of this year. In this case, a Metro driver was forced to hit his train's emergency brake because he realized he wasn't slowing down as he entered a station. The incident was caused by a single failed relay on a subway car, Metro explained.

The NTSB investigation also highlighted the fact that there is a little known Metro Tri-State Oversight Committee that is supposed to be concerned about Metro safety issues, but as another Post story noted,

"The committee has no direct regulatory authority over safety and cannot order Metro to make changes. It has no employees of its own and no dedicated office, phone or Web site. It borrows space for its monthly meetings, which officials said no member of the public has ever attended."

Makes you wonder why it even exists.

Yesterday's Post story pointed out a particular automation safety design problem in the Metro system. Even though drivers are operating their trains in manual mode because of suspicions concerning the reliability of the automated track control system knowing where trains are, the drivers still depend on the automated track control system to tell them how fast they should go based on where it shows other trains are.

Another worry is that the Metro train driver contract that specify how long drivers need to be at the controls before they can get a break (5 hours and 45 minutes) was based on an implicit assumption that drivers would be operating their trains in mostly automatic mode. Operating all the time in manual mode may increase the fatigue of drivers, leading to additional safety concerns. Metro management says that it isn't worried, since there have been other times that drivers had to use manual mode for extended periods. However, this time looks to be far longer.

Operating in manual mode also increases journey times on the Metro, which, in combination with the after affects of the crash, may partially explain the drop off in its passenger ridership numbers in July.
 

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An IBM Quantum Computer Will Soon Pass the 1,000-Qubit Mark

The Condor processor is just one quantum-computing advance slated for 2023

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This photo shows a woman working on a piece of apparatus that is suspended from the ceiling of the laboratory.

A researcher at IBM’s Thomas J. Watson Research Center examines some of the quantum hardware being constructed there.

Connie Zhou/IBM

IBM’s Condor, the world’s first universal quantum computer with more than 1,000 qubits, is set to debut in 2023. The year is also expected to see IBM launch Heron, the first of a new flock of modular quantum processors that the company says may help it produce quantum computers with more than 4,000 qubits by 2025.

This article is part of our special report Top Tech 2023.

While quantum computers can, in theory, quickly find answers to problems that classical computers would take eons to solve, today’s quantum hardware is still short on qubits, limiting its usefulness. Entanglement and other quantum states necessary for quantum computation are infamously fragile, being susceptible to heat and other disturbances, which makes scaling up the number of qubits a huge technical challenge.

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