EDITOR’S NOTE (May 20, 5:20 p.m.): After this article was published, a Washington-based website, Greater Greater Washington, disputed the article’s premise and said FiveThirtyEight counted more incidents as fires than the Metro system’s own count. Our article, based on the numbers reported on IsMetroOnFire.com (which it compiled through Twitter), said there had been 73 incidents of fire in the first three months of 2016, while in a report Metro said there had been about two-thirds as many instances of smoke and fire in the same period.

After FiveThirtyEight discussed the discrepancy with Nick Stocchero, who runs IsMetroOnFire, we learned that the website includes instances of smoke in the subway system that Metro would not consider a fire or smoke condition, such as malfunctioning train brakes that fill a station with smoke, or a third rail that is arcing so severely that the fire department is called. There may also be instances of double-counting the same incident. Our article should have noted that Metro keeps a count of fire and smoke incidents that is lower than the website’s list because of different definitions of fire and smoke conditions, and that the website contains instances of double-counting. As a result we changed the headline to reflect the uncertainty.

WASHINGTON — Is it hot on this subway platform, or is it just the fire on the tracks?

The Washington, D.C., subway system is a mess — chronic delays, malfunctioning air conditioning and, earlier this year, it was shut down for a whole day because it was not safe to ride. The secretary of transportation has considered shutting down the whole system because of safety lapses, and the Metro system’s proposed solution involves shutting down five stretches of track entirely for at least a week (and single-tracking others for up to 42 days). Ride-sharing services are licking their chops.

But the most damning indictment of the subway system may be the existence of IsMetroOnFire.com, which lets commuters check which lines are currently on fire. I studied IsMetroOnFire’s associated Twitter account to see how bad things have been this year, and it hasn’t been pretty:

The good news: Metro’s one-day emergency shutdown may have helped! During the day of repairs and inspections on March 16, workers found 27 power issues, including frayed cables in three different sections of track that were so badly damaged that trains shouldn’t have been running over them at all. Since, for once, these problems were caught before they caused a conflagration, there appears to have been a lull in fires for a little while after the shutdown. But the respite was short lived. Since April 23, there have been 3.5 fires a week.

Overall, IsMetroOnFire logged 85 fires by May 16, or a little over four per week. And IsMetroOnFire is more likely to be undercounting fires than overcounting.

Initially, Nick Stocchero, who runs IsMetroOnFire, began by keeping track of official Metro alerts himself, but since December of last year, his website and Twitter account have scanned two Twitter accounts (@metrorailinfo and @metroheroalerts) for fire-related words (“fire,” ”smoke” or “fd”) and the name of the affected lines. The D.C. Metro system doesn’t always reference fire explicitly on Twitter when a fire is causing a delay, so not every fire is caught by this method.

TRAIN LINE FIRES Silver 55 Red 48 Blue 48 Orange 28 Yellow 19 Green 13 2016 fires by D.C. Metro line, through May 16 One fire can affect more than one metro line. Source: @Ismetroonfire via twitter

The Silver line, despite being the newest line, had the most fires. However, because IsMetroOnFire doesn’t always record the station where a fire occurred, these fires may have happened on older track that the Silver line shares with the Blue and Orange lines. A fire typically results in a delay for all the lines that share the tracks.

With numbers like these, D.C.’s commuters may prefer to walk in the coming summer humidity rather than ride on the intermittently enflamed rails.