WIP video about Escalators - Urgently Requesting Feedback!
Added 2025-09-08 19:07:11 +0000 UTCWe've got an exciting video coming out very soon!
We’d love to hear your feedback and suggestions as we wrap up this video all about Escalators (it's still pretty rough around the edges in some places).
Is there anything wrong? Any other questions? Anything more you'd like to see? Explanations you think don't do a good enough job or lack depth? Let us know!
Thank you so much!
-Team Ve
Comments
I see I'm late to the party here...
Michael R Wilson
2025-10-24 19:36:47 +0000 UTCWould a second backup motor that could kick in and resist the acceleration of the steps be a way to prevent the accident. The fact that the second motor 'steps' in could engage the first brake and bring the escalator to a stop in a controlled manner. I picture the situation with the final brake that jams the chain as possibly causing all the riders on the escalator to fall forward with those above rolling forward and crushing those below. As with stampedes in fire and other emergency exit situation people can die from crushing, especially children.
Michael R Wilson
2025-10-24 19:34:30 +0000 UTCGeneral question, how does this escalator design handle a mains (utility) power failure? Is that worth covering? I was thinking about this and it needs failsafe behaviour for this condition. If this is achieved with the third last recourse brake then perhaps that causes the temptation to disable it, particularly if there's a cumbersome/laborious reset process. I.e. if you have a brief power cut you might need to call an engineer out and it could take several hours to restore operation. I'd imagine the (full) accident investigation would either explore this or trigger a second investigation into why it was or might be disabled? From a human factors point of view I think it's important to cover the reason and motivation for this. At 19:30 it mentions: "deliberately sabotaged to avoid escalator shutdowns" - the use of the word sabotage seems questionable and I'm not really sure what that means. I'd speculate it could also have been an unreliable batch of components (like a solenoid) and a dangerous workaround for that. Do you have a link for the original accident report (in Italian)?
Kevin Walters
2025-09-11 16:49:46 +0000 UTCI would say compiler warnings are a bit different, there's lots of levels of those and some are harmless depending on use. These appear to be correctly implemented health checks performed from the program in firmware that were somehow selectively disabled post commissioning. As I mentioned in my other post, I think the output shown at 17:45 should be marked if it's simulated output. I'm also curious what "the error log" is. Is this volatile memory of the system? Is this non-volatile memory and kept for N entries or X time. At 15:56 it mentions "the error codes had been turned off". It's possible but I am a little surprised that the software has this feature. I'd be interested to know if each elevator could be configured to enable/disable checks or if it was a new release of the firmware. At 18:05 it mentions "someone must have reprogrammed the system to stop recording fault codes" so perhaps this was updated firmware? Would also be interesting to know if the elevators are networked back to a local monitoring point in the station or all the way back to the Rome transport operator and/or escalator vendor/maintainer.
Kevin Walters
2025-09-11 14:39:02 +0000 UTCFlippant section. Great to see spiderman and Danny McBride interviewed. Mr Nasser is about 250% on the Muller excitability scale. And the way to get down an escalator quickly and safely (?) was demonstrated in London a few years back: https://www.youtube.com/watch?v=rlF4nRUbKmc
Kevin Walters
2025-09-11 14:21:31 +0000 UTCInteresting video, I like the animations, fun to see your "rough cuts". Perhaps I missed it but would be interesting to see the calculations for loading. There's a comment about elephants and step load but I wasn't sure if that covered the rest of the mechanical system. People are getting fatter so many people carrying systems are having to adapt to increased typical loads. At 1:05 the animation shows brake glowing red hot and some sparks flying off the brake. More-so at 1:15. It looks nice but if this doesn't really throw sparks (an ignition source) in either scenario then it's misleading to pretend it does. At 1:30 what is that (non-moving) piston thing next to the last resource brake on a spring? Nitpicking, at 16:37 "lock it in place" and 16:43 "bring the fully loaded escalator to a halt". This makes me wonder if it's an immediate halt. An escalator which goes a bit faster and then near instantaneously halts is going to throw passengers forward and that sounds like a big risk on a downward escalator. Perhaps adding "to a halt in N seconds." would be good here? At 16:43 vidoe freezes for about six seconds but audio is okay. Perhaps that's a bug with Patreon's streaming (for me)? FYI in London (UK) there was a serious deadly fire at King's Cross Underground station in 1987 (just outside the railstation now famous for Harry Potter). This was caused by a failure in the cleaning regime, accumulated debris and an ignition source assumed to be cigarette or match. This was the era of wooden steps but it would be interesting to know if fire risk is eliminated with metal steps. It also highlighted that the contained space caused what's now called a "Trench effect". https://en.wikipedia.org/wiki/King%27s_Cross_fire National Geographic documentary: https://www.youtube.com/watch?v=PBbJXvJYeq0 On audio front, 18:44-19:25 narration is lower level than rest of video. Music isn't ducked for Derek's dulcet tones at 21:27. At 17:50 it would be nice to mark this as simulated output if it's not genuine output from this type of lift system. The use of English suggests to me it's simulated "for TV" output. I need to re-watch it but is there any mention of energy saving escalators? I've noticed some escalators slow down when they aren't used for a while and then notice when a person uses them and they gradually return to normal speed. It may be a myth but I thought I saw/read something about escalators once that said they were all custom sizes. It was probably about building a new place and showing a preconstructed unit being lifted in.
Kevin Walters
2025-09-11 14:15:06 +0000 UTCMy comment is not an informed comment, perhaps false triggering for #3?
Kevin Walters
2025-09-11 13:54:31 +0000 UTCOnly seen the first five mins yet, the Italian gentleman's accent is quite strong (the one who is talking about escalators being generally safe, though it's not told who he is exactly). Subtitles/captions might help for his bit, unless we are relying on global Youtube captioning. Will try to watch the rest soon. A fairly unexpected and interesting topic, as always. Thanks.
Vishal Bondwal
2025-09-10 10:43:22 +0000 UTCI just want to say the use of the word break versus brake (both correct and incorrect) in this comment section, is quite hilarious.
Dorus Peelen
2025-09-09 20:03:56 +0000 UTCFascinating video. I like the overall structure of the presentation. My only comment is regarding the section about the regenerative nature of the down escalators. Your summary with the animations is great, and then at the 14:49 mark, there is the commentary about the original escalators having this feature, which is fine. However, I felt that the reaction part of the conversation was a little out of place because we've just been told about the regenerative features. Perhaps rearranging the flow to have the conversation before the detailed animation. Or perhaps just omit the 15:03 - 15:30 portion.
Ray Konopka
2025-09-09 19:39:55 +0000 UTCGood video. I'm surprised I never heard of this issue or event. Thank you for doing this, as it was very interesting. I went through all the other comments, and so many are spot on that I just added to their likes. One thing, though, I didn't see mentioned, but I know you probably know, the audio level changes made it hard to listen to.
Donald J Arndt
2025-09-09 16:25:06 +0000 UTCMy interpretation about the safety systems of the escalator is that their effects add-up successively, not replace the failed ones (since the motor still functions as a generator and the friction brakes still rubs against the flywheel at the time when the final brake engages into the wheel). If the video plans to suggest improvements (being an engineering video document), I find surprising that the escalator (system) does not warn people (riders? travellers?) about the imminence of a critical situation. There are enough points in the system that could do that, one being the actual current drawn (or generated) by the motor. Audio and visual warnings could come off, warning of possible danger. Additionally, physical light barriers (thin plastic strips) could be actuated, since some escalators already have bollards at the access point. Another topic that could be interesting to discuss is human psychology in such circumstances. (I still remember the triggering factor of the excessive sway at the inauguration of the Millenium Bridge in London.) Since those behind the access point of a downward escalator do not see what is happening on it, they will continue to press those ahead of them. (Maybe a top mirror could help.) Thus, those who suddenly see the danger from the top landing cannot stop or turn around. Overall, the video is interesting and informative, although more engineering-oriented information would help. Also, in my opinion, the interviewer is "too casual" for the profile of the videos on this channel and the interviewed person needs some introduction. Personally, I find that the "street questionnaire" does not add much value to the video.
Costan
2025-09-09 14:32:07 +0000 UTCWill ask the team now for you! Thanks for this. - Matt, Publishing Lead
Veritasium
2025-09-09 10:18:07 +0000 UTC0:46 I want whatever the headbanging people are having
SkaveRat
2025-09-09 05:39:23 +0000 UTCGreat video. enjoyed it a lot.
Roye
2025-09-09 05:07:26 +0000 UTCThe rationale behind the maintenance crew zip-tying the mechanical backstop is unclear. The backstop is designed as the third line of defense, after cutting power to the motor (#1) and engaging the main brakes (clamping arms, #2). By design, it should only engage as a last-resort fail-safe, and when it does, it means the system is already in a highly unsafe state. Because defenses #1 and #2 would handle almost all normal events, the likelihood of the backstop (#3) engaging during routine operation is extremely low. False positives at this stage would also be statistically negligible. In other words, the backstop isn’t something that would be “in the way” or causing nuisance trips for the crew. That raises the real question: what did the crew think they were gaining by zip-tying it? Disabling defense #3 eliminates the final safeguard while offering no obvious operational benefit. Since this is clearly a human decision, understanding their reasoning (however flawed) is critical and I feel is lacking here. Anyway, great video as always! Loved it! :)
Ravi Palani
2025-09-09 01:53:52 +0000 UTCExcellent and informative, as usual. At the start I was wondering which way this video would go, mechanics of the thing or failure investigation. You did both quite nicely. I am looking forward to the finished version!
Charles S. Cook
2025-09-09 01:08:51 +0000 UTCPersonal commentary: I smell an investigation (by the authorities, I'm sure you did your homework) that did not consider the software. People can and do disable compiler warnings because they are annoying and reap the consequences later. I suspect something similar here. Based on the report excerpts @19:26, there is "so-called fault code memory" (not sure what is "so-called" about it). Embedded systems don't have a lot of memory for anything, let alone logs. If that space fills up, and the system wasn't designed for (or just not set up with) an external logging system with plenty of space, then logs could build up until there is no more space. Now we get a split in software design philosophies over how to handle this bad situation: (1) Overwrite the oldest logs (ok) (2) Preserve existing logs and stop writing new ones (bad) (3) Crash the entire system (very bad; also common) If #3 was the situation, then the escalator would break down periodically just due to running out of its limited memory, and the owners would have to call out contractors from the escalator's installer (at their preferred rate, of course, because captive audience), and they would have to clear out the logs themselves after performing maintenance before turning it back on. If. If there wasn't a lot of memory, then I'm wondering if this was a common occurrence. Or maybe there was a software update that needed more space, the embedded system was already pushed to its capacity limit, and rather than replace the entire control system, a decision was made (by engineering, by engineering management, by upper management, don't know) to update the software in place. Not having access to the report myself (not linked on wikipedia), I'm just speculating
chromicacid
2025-09-09 00:55:56 +0000 UTCOh, and the wikipedia page says that the cause is still unknown to this day, and offers no reference to that 100 page report: https://en.wikipedia.org/wiki/2018_Rome_escalator_accident Since the report took 2yrs to come out (IIRC from the video), I'm wondering if the last edit to that page was prior to the accident, or if a different wikipedia page was made entirely. Is someone on your staff a wikipedia editor who can update this?
chromicacid
2025-09-09 00:31:59 +0000 UTC@2:09 *person being interviewed* Can we get an introduction? @3:01 "...but maybe it's more similar to the origin..." Retrospective comment after finishing: How is this accident similar to the origin? Were the original escalators not maintained? @4:56 "...because ankles only flex about 12 degrees comfortably" Nitpick: 10-20 degrees from flat to highest (dorsiflexion) and 40-55 degrees from flat to lowest (plantarflexion). Point taken though :) https://pmc.ncbi.nlm.nih.gov/articles/PMC4994968/ @5:30 animation of moving stair Nitpick: First animation doesn't attach the red stair lines to the white line as it goes around the corners. Second (extended) animation does though. @5:56 "Clearly, we have steps going around in some or loop, but ..." You sound dead tired in this recording. @7:07 (breath intake) Audio cut a bit late @10:59 *new person interviewed* Can we get an introduction? @13:07 - 13:25 The chatter about using the "2% faster" observation as a way to impress your friends is cute, but for a Veritasium video, this feels out of place. @14:05 "...which then create their own magnetic field." I'm not sure what the red highlight is supposed to represent (going up and down the coils), but I'm not understanding it as depicting an opposed magnetic field or a breaking force. @14:41 "...they're actually generating electricity." Is this a good thing? Without buffer storage, a dozen escalators in a large building being a dozen variable generators would put a lot of strain on whatever electrical system it fed into as a generator somewhere is under constant change to compensate for the voltage shifts. @17:25 "...had physically tied plastic straps..." Can we get the thing circled in the photo? The music swells dramatically and zooms in (very slightly) on a brass pipe or something. I'm not sure what to look at. @18:19 (breath intake) Audio cut a little late. @19:06 "The criminal report found that Metro Roma and ATAC were working hand-in-hand." Video does not align with the statement. The highlighted text is a quote pulled mid-sentence from an external report partially quoting the 100 page paper. It's not clear if this is a statement from a prosecutor, a conviction from a judge, or commentary on the situation from someone else, and it is not clear why this is evidence for working hand-in-hand.
chromicacid
2025-09-09 00:27:56 +0000 UTCDiscussing safety at 21:26, the escalator is ascending. To reflect the incident, it should be a descending escalator since that is the type of load that the safety systems are meant to protect.
Walker Mangum
2025-09-08 22:40:16 +0000 UTCDuring the accident, was the power to the motor really cut? That would mean, that the regenerative breaking would stop working, correct? - That feels wrong.
Martin Hinterndorfer
2025-09-08 22:18:49 +0000 UTCWatch to the end.
Kat Seibert
2025-09-08 20:56:23 +0000 UTC16:30 I also wondered about this, in some motors you can also short the windings or use a small resistor to load the motor. Maybe a little more detail here would help.
Kat Seibert
2025-09-08 20:54:38 +0000 UTCUnderstand your concern here although I think in this case the torque is more important than the HP but maybe that also is not a good reference for the average viewer.
Kat Seibert
2025-09-08 20:51:08 +0000 UTCHere are some thoughts and suggestions: - The capacity of an escalator apparently decreases as the speed increases; why is that? - More factual information about escalators would be interesting (which one is currently the longest, tallest, fastest, most beautiful, …). - In my opinion, the story about the accident in Rome takes up too much time. It would work better if it only appeared at the beginning and the end as a framing narrative. - I have observed that in India people usually stand on the left and walk on the right. Could this possibly be related to left-hand traffic?
Lo
2025-09-08 20:41:40 +0000 UTCOverall, a good video. - People in the street “when were they made” feels long - The whole section on the interview of the frictional wheel feels unnecessary. - The interview with the regenerative braking feels unnecessary, too. Actually, though interesting, I might remove the whole aspect of the regererative aspect. It’s kind of distracting and peripheral. - The second time the accident is described it feels redundant. - It would have been good if there was some foreshadowing in the beginning about the safety of escalators, and they weren’t sure why it failed. Then, go into the history of escalators, then go into the sabotage of the escalators as the cause. - Also, with the interviewees on zoom, it would be nice to have subtitles. Neat video, though!
Sheldon Carpenter
2025-09-08 20:19:23 +0000 UTCI found the whole video super interesting, but jumping right into the timeline felt like I’d started watching from a few minutes in. Obviously a title and a thumbnail will help, but I feel like we need a quick overview of the incident to start with before the timeline. Eg. “On {date}, while football fans were making their way to a football game, an escalator suddenly lost control, sending passengers hurtling down to the bottom. So how did this happen and how do escalators work…” then continue with the timeline.
Sam Bebbington
2025-09-08 19:40:43 +0000 UTCWith all respect, the gentleman who interviews the escalator expert is really irritating. "Like," "wow," "are you kidding," "My mind is blown." etc. That feels unprepared and unprofessional.
Kate Proctor
2025-09-08 19:39:25 +0000 UTC7:30: What’s a “reinforced steel chain”? Steel reinforced with what? Is the meaning just “strong steel chain”? Or “multi-row steel chain”?
Jordan Singer
2025-09-08 19:28:32 +0000 UTC6:40: If you want to compare the power of the motor to a car, quote the horsepower. Kilowatts invite a comparison to things like electric space heaters, at least in the US.
Jordan Singer
2025-09-08 19:25:44 +0000 UTCThis seems to be a more Engineering focused video, so we, engineers, work with parameters. DO we know the parameters of number of people, max weight and etc? 01:30 What caused the last break to fail? (just tell you will tell later in the video :] ) 02:20 Who is that person? 10:30 WE still have a dangerous situation with the groove - https://www.youtube.com/watch?v=anjH3D5FWME 16:30 If they cut the power, they also cut the generator part and maybe the motor did LESS resistance that it could do generating energy.
Marcelo Henrique Gonçalves
2025-09-08 19:23:14 +0000 UTC“The third line of defense failed” — For the first two there was an explanation of the failure. But nothing about the third. Each of the three systems should receive an equally clear and concise explanation as they are introduced. For the first — the motor — I heard something like “the drum began to slip”. What does this mean? What drum? For the second, the friction brake on the motor shaft, the animation shows a red-hot brake drum and sparks flying from the brake shoes. The narration doesn’t quite match this. I’m only a few minutes in but this caught my attention.
Jordan Singer
2025-09-08 19:18:11 +0000 UTC
