Doors on the D.C. Metro Can Take 15 Seconds to Open After the Train Stops. Why?

Photo by Matt 📸 on Unsplash

The train stops. People shuffle to the door, crowding around it. The doors stay shut. The announcement overhead declares what station it is and what the next stop is. The doors stay shut. People shuffle a bit more, pressing the people in front a little more against the glass.

The doors eventually open, but not before impatient sighs, tapped feet, and questions from tourists about if the doors will open at all.

This delay is what is known as dwell time or “the time a train stands at the platform usually for the purpose of allowing passengers to board.”

Dwell time is something that ideally should be minimized — after all, dwell time affects travel time and that affects scheduling. But there’s an important balance that must be struck between time and safety, and in that calculation safety is of course always the more important consideration.

All the same, dwell time adds up, and needless dwell time is a major frustration for commuters as it causes annoying delays. So as WMATA works its way Back 2 Good, why do Metro trains have doors that take so long to open?

What causes delays in transit

Before we get into the question of whether or not the Washington D.C. Metro is better or worse than other transit systems in terms of delays, let’s first briefly get into what can cause delays in transit. Outside of catastrophic safety failures and unusual accidents, there are a few things that commonly cause delays.

The whole of any transit system is a balance of time. Human controlled and dependent elements — ranging from human drivers to the humans boarding and exiting the train — add in variables that are not always resolved in the expected time. Without fail, offloading and onboarding passengers is the main cause for delays.

For one example of a type of passenger caused dwell time, think of someone running to get to the train who then slams their whole body between the closing doors despite being reminded that the doors don’t work like elevator doors. The doors open. The person boards. But, there’s another person behind them, running, and when the doors try to close again, that person slams their body between…