Or at least USCSB's animation company. It's the same sort of deal--a relatively dry semi-technical presentation for those that don't necessarily need to dig into the deep details--but somehow USCSB makes it seem more like a short film (or a "Mayday!" episode), and this sounds like a second-year college student giving a powerpoint presentation to the class on a subject they don't really care about. Gonna get a lot more engagement by doing the former.
If a train details on a straight section of track anywhere except the front of the first car, the section of the train in front of it will apply forces that would tend to pull the train back onto the track. But even this was not enough. The train also needed the frog of the next junction to jump the wheel back over and into the track. (A frog is a section of the track that rises above the rest of the track to allow the train to jump onto an adjacent track. They are completely used at junctions where tracks merge. In this context, the frog just did exactly what it is normally designed to do, just with the opposite wheel from the one it would normally affect.)
Over the summer of 2021 I rode 7200 on the Yellow Line over the Potomac and I could feel the car shaking side to side meaning the wheels were oscillating. I was thinking to myself "this thing feels like it's going to derail and sooner or later they're going to find out and then what, remove all the 7000 series from service? They can't do that." A few months later that's exactly what happened...
@@tylerp6375 in aviation there's a bright dye applied to important joints that stains metal (and skin) very well. A few diagonal strips of the dye marker to the axle-wheel join will show as broken lines if the wheel migrates
Was the cause of the out of spec. wheel sets, usually due to the migration of, one of the wheels or both of the wheels? Are there brakes on these axles? When in use, is there a temperature difference between the axle and the wheel? When the wheels are pressed onto the axle, are any chemicals used to prevent migration (similar to a bearing retaining compound)?
Why can't these axles have some kind of attached stop beyond the wheel location on the outside, like an oversized cotterpin/bolt etc. This would prevent the wheel migrating at all. Even small engine equipment has this. I think this is ridiculous that they do not.
They wherent self rerailing. The second frog of the cross over was rerailing them Then when hitting a switch that wasnt a cross over it stayed on the ground
No one really knows at this point. Metro and Kawasaki are both blaming each other for this. It could honestly go either way in my opinion. Metro has a poor safety record, but US passenger rolling stock manufacturers have been putting out trains with serious defects for the past couple of years (Alstom's Avelia issues being the most notable)
This is almost certainly Kawasaki’s fault. Kawasaki made the cars, and since none of the other types of cars on the Metro have this problem, we know it’s not the track or anything else WMATA does.
@@michaelimbesi2314 Right, but it Kawasaki says "inspect the wheels every 30 days, lube this part and maintain this part" and WMATA is not doing that it's hard to blame Kawasaki.
@@gotacallfromvishal Yes, and we're talking about "migration" which is an expected condition of aging stock. That's why the manufacturer has an inspection and maintenance procedure for the assembly. If WMATA failed to inspect and correctly maintain the wheelset, chances are Kawasaki will be minimally culpable. WMATA may counter that the prescribed maintenance and inspection procedures and schedule were faulty or insufficient for the task, or that there is a manufacturing or design defect (the latter a tricky thing as WMATA is still using Kawasaki rolling stock)
These new trains are junk. Lots of huge problems, like this, wiring not to spec, and reliability. WMATA needs to cancel the order and find another manufacturer. This is just the beginning of the problems with these.
I'm sure that was a jarring ride for any passengers in that rail car! And the shocking thing is the 7000 series cars are the newest ones in WMATA's fleet.
Why are these width checks being ignored? 30/80 total out-of-limits sets before an accident requiring fleet checks is pretty poor, not the worst, but certainly a poor show. Are the engineers being over stretched? Are the bean counters cutting corners? Is the importance of this check being undervalued?
There's a difference between "out of spec" and "dangerously out of spec". You expect to find plenty of the former when performing maintenance, that's why you're doing it. You expect to catch everything while it is still only "out of spec" and before it gets to "dangerously out of spec" during maintenance. And unless you have some sign of stuff going "dangerously out of spec" between maintenance dates, that's it. Here, they got a sign and added extra checks in addition to the normal checks during regular maintenance.
@@HenryLoenwind that's a poor interpretation. If your maintenance is finding items out of spec you reduce the periodicity to increase the frequency or you have more stringent maintenance to keep the items in spec. Keeping things within specification keeps their failure modes predictable and thus "fail to known condition". Letting things go outside the calculated envelope leads to tragedy, they're lucky nobody died.
@@ThePlayerOfGamesI think we are using 2 different definitions of "spec". I was using "the value range it has to be within when manufactured or maintained to as-new condition". You are using "the value range it can safely wander from above between maintenances". You don't want those two ranges to be identical, or your maintenance interval would have to be 0 (the value WILL wander between maintenances). Any good machine will have both (or more) in its spec sheet. For example, the tread depth of the tyres on my car has a "prod spec" of ">6mm", a "maintenance spec" of ">3mm", and a "usage spec" of ">1.6mm". So when I bring in my car for service and the tyres have 2mm, that's out of "maintenance spec", but only in as far as it triggers maintenance (replacement) for those tyres. Was it to come in with 1mm, we'd look into why the tread depth reduced more than expected.
it took several minutes to determine the narrator was saying "widened wheel set" - every time it sounded like "waadin wheel set" as if it was a brand name or something - slow your speaking cadence and annunciate clearly when you have such a thick regional accent like that
Maybe it’s just me but maybe the NTSB can hire someone to do these voiceovers so we don’t have to try to concentrate what this man with a thick southern accent is actually saying.
Im not even American and i can clearly understand everything he is saying while watching this late at night with volume really low. Maybe the problem is on your end/ears. (you can turn on Subtitles if you have hearing difficulties)
