Credit: Sound Transit

Two years ago I wrote a piece about the frequency and duration of Link service interruptions (blockages, accidents, power outages, etc). Given the recent, high-profile service meltdown on June 12, it makes sense to revisit the issue. How often do interruptions occur? How long do they last? Have they become more frequent or longer in duration over the last two years? I parsed several hundred email alerts from Sound Transit to find out!

I measured interruptions starting in December 2015, when I started subscribing to the Sound Transit rider alert emails. From then up to June 28, 2019, I count 144 separate incidents*. That’s roughly one interruption every nine days and is the same rate I estimated in my 2017 piece. Counting the number of interruptions in 30 day intervals confirms that the base rate of these incidents has been quite stable, in a statistical sense.

So, the data do not suggest that interruptions have become more frequent. But have interruptions become more severe in duration? As in 2017, I summarized the length of interruptions in a chart that classifies incidents in four categories (quartile groups) of duration severity.

The level-4 events are usually the memorable ones and tend to involve major accidents or power outages. For instance, the longest duration event I found was due to a 6-hour long power outage somewhere between Othello and Tukwila on August 8, 2017. Our recent bad day shows up in the red on June 12, with a nearly 4-hour disruption. These durations are calculated from when Sound Transit sends out their “service interruption” and “service resumed” emails – so, the data here depend a lot on the quality of ST’s reporting to the public. That said, there have been more level-3+ incidents from January to June in 2019 than in other years. On the other hand, the 2016 count isn’t far behind. And the median duration has remained at about 25 minutes, the same as when I last calculated it in 2017.

Have Link service interruptions really gotten worse? The data I have suggest not so much – at least at a high-level. But that is small comfort when you’re trapped on a stuck train or waiting at the platform during one of these incidents.

[*] Incidents are counted from ST alert emails, so my data could under-count the real number of service interruptions.

8 Replies to “Is Link light rail seeing more service interruptions?”

  1. It’s curious there haven’t been any (reported) <10(?) minute disruptions reported by ST this year. Is that a change of policy to not call those out? Or maybe they've actually ironed out the smaller delays by kicking buses out of the bus tunnel in March?
    I wonder if anyone has done a similar analysis of regional freeways to see the frequency of highway system "breakdowns" due to vehicle incidents. Maybe traffic jams from crashes/car breakdowns isn't a fair comparison to transit backups from train/track breakdowns.

    1. It’s not an exact comparison because one is professional drivers carrying passengers in bulk (many people, few vehicles), while the other is a combination of amateur and professional drivers carrying themselves, freight loads, etc, to more destinations. But the impact of incidents is the same: a bottleneck or complete stoppage that may last for hours.

      There are blocking incidents and traffic spikes almost every day somewhere in Pugetopolis. This morning the radio reported something and said Lynnwood-Seattle is taking an hour. We don’t notice how many there are because they occur drip by drip.

      When I reverse-commuted between downtown and the U-District before U-Link, there were backups at least three times a week that made the buses unpredictable. Once or twice a month it would turn a 25-minute trip into a 45+ minute trip. Link’s problems are like a tenth of that.

      Also, some of Link’s problems are due to inaccurate next train signs. It sometimes says the next train is 20 minutes or 30 minutes, and then it comes 2 minutes or 5 minutes later. That’s common enough that a security guard at Capitol Hill Station mentioned it. It used to happen a lot on RapidRide B the first year although then it got a lot better.

    2. That estimate was only about train movement. Al S below reminded me about escalators. Escalator/elevator outages are much more common. A side-by-side comparison might show that whenever there’s a blocking incident on a highway, an elevator or escalator breaks somewhere along Link.

  2. I watch the Rider Experience and Operations Committee attachments. There was lots of interest changing this committee name from just the Operations Committee to highlight rider experience issues last year.

    After regular proclamations on improving performance disclosures, Iโ€™ve seen nothing since the April meeting:

    https://www.soundtransit.org/st_sharepoint/download/sites/PRDA/ActiveDocuments/Presentation%20-%20Completing%20the%20Picture%20-%20Enhanced%20Service%20Performance%20Reporting%20190404.pdf

    In this April presentation, this issue is combined into generic on-time performance. Of course, the Board should differentiate between a slightly-delayed train and a major service disruption.

    The change in reporting โ€” and the pulling back of providing performance reports generally โ€” probably needs to be discussed here and probably needs for comments to be sent to ST staff and board members.

    At a quick glance, the April presentation did not discuss:

    – long-term disruptions
    – train overcrowding
    – elevator/escalator failures

    There are probably other issues worthy of disclosure.

    The reporting video at the meeting suggested that reporting would be enhanced in coming months, but Iโ€™ve seen little to nothing about this since April.

    1. +10 Agreed.

      When was the last time ST simply put out a monthly ridership report?

      I see a lot of lip service from ST about improving the performance reporting with few results to show for it .

    2. It seems like generating and publishing the monthly Sound Transit Ridership Report as they did until February 2019 really could not have been that much trouble. Sound Transit must have all the ridership, reliablity, and farebox numbers in a database, and the reports have a standard format- generating the PDF shouldn’t take much more effort than running a script or clicking a button.

      It’s disappointing that they’ve discontinued sharing this data with the public.

  3. What frustrates me about any Light Rail interruptions are the vague text messages that ST sends out as they don’t tell you the extend of the interruption as all they say there is an interruption.

    Is the interruption affecting the entire system and no trains are running or is it just the south portion or the north portion or what. You are left in the dark on the extend of the interruption and if you are about to take Light Rail you wonder if you should use alternate transportation instead.

    I wrote an email to ST a couple of years ago about this and the response I got was that they want to sent out the text as quickly as possible about a problem which is a nice idea but when that text doesn’t say anything about the extent of the problem it doesn’t help the riding public in what they should to.

  4. If ridership is still going up, while interruptions remain stable, more riders are affected.

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