News Monorail Red in motion with guests on board and doors open

prberk

Well-Known Member
One day, the thread search function will be used...
View attachment 326320
You missed the larger point that I was making in my last post -- which I, in fact, identified as a larger point. (Perhaps you can search "larger point" and find it.) Yes, I probably could have searched for the author once he had responded saying that he had put the report several pages ago; but it would not have solved the initial and larger issue of recent news getting lost in pages of discussion whose title was specific to a whole different incident. It happens a lot here, but it used to be different. We could come here before and immediately see what was new by new threads more specific to an incident.

Anyway, not a big deal, just easier to identify the topic and better to gauge whether or not to open a thread.
 

s8film40

Well-Known Member
To me, the door didn’t fall off since it was still attached to the monorail. How can the door be classified as “falling off the monorail” when it is still attatched to the monorail?

It semantics but I think words matter.
It's not as if a maintenance person detached the door and lowered it into that position. That would've been incredibly stupid and dangerous. It seems obvious it detached from the impact and while they were investigating what was wrong with the door it fell to the position seen in the photos.

To me the real core issue here is that a scooter impact broke the door from it's hinge. The thing is these trains have been going for 30 years and seen a lot of abuse without that happening. And trust me these doors have certainly been hit by scooters many times. I've personally witnessed it happen more times than I could ever count. So the question is has something happened with maintenance to make these weaker or is it simply after 30 years the result of metal fatigue or brittle fiberglass.
 

trainplane3

Well-Known Member
You missed the larger point that I was making in my last post -- which I, in fact, identified as a larger point. (Perhaps you can search "larger point" and find it.) Yes, I probably could have searched for the author once he had responded saying that he had put the report several pages ago; but it would not have solved the initial and larger issue of recent news getting lost in pages of discussion whose title was specific to a whole different incident. It happens a lot here, but it used to be different. We could come here before and immediately see what was new by new threads more specific to an incident.

Anyway, not a big deal, just easier to identify the topic and better to gauge whether or not to open a thread.
Sorry. I wasn't directing it only at you. Many people just don't know about the thread search function. Really wasn't trying to be mean, just making a point the feature in threads exists and is super useful.
 

fngoofy

Well-Known Member
Even if rammed from the inside out, shouldn't the door hold against such an impact?
How much momentum could a scooter gather side to side within the cabin?
It isn't momentum as much as torque. If it hit and the operator of the scooter doubled down on the throttle, there is enough torque apparently to push it off its hinges.
 

Jimdalva

Active Member
While not necessarily a prescription, private entities are allowed to ask to see a "State-issued disability parking placard or card or a State-issued proof of disability, that must be accepted as credible assurance on its face."


BUT my "State-issued disability parking placard" will be hanging in my car in the handicap parking lot!
 

s8film40

Well-Known Member
While not necessarily a prescription, private entities are allowed to ask to see a "State-issued disability parking placard or card or a State-issued proof of disability, that must be accepted as credible assurance on its face."


BUT my "State-issued disability parking placard" will be hanging in my car in the handicap parking lot!
I'm pretty sure they're not allowed to do that. Not to mention these things aren't even specifically intended for for people with disabilities. That's why Disney calls them ECV's (Electric Convenience Vehicles).
 

Lensman

Well-Known Member
It isn't momentum as much as torque. If it hit and the operator of the scooter doubled down on the throttle, there is enough torque apparently to push it off its hinges.
The maximum force that even the torquiest motor could apply to the door would be limited by the coefficient of static friction of the rear driving wheels. At some point, they would start skidding.

So if we know the weight of the ECV + rider + child as 500 pounds and using 0.79 as the coefficient of friction of synthetic rubber on cut pile carpet*, we can estimate that the maximum torque that could be applied by the motor onto the door as 400 pounds of force or 1800 newtons. As per the estimate in the other thread, the impact of the ECV going from 5 mph to a full stop in 100 milliseconds is about 5000 newtons.

It's not insignificant, but I'd still go with the impact force as being the primary cause of the shearing force on the door hinge.

Also note that this motor would need about 360 Nm of torque to achieve 1800 newtons of force on the door. This is about double the torque of a 3000 watt motor I found referenced in a 50 mph racing scooter being discussed over in the electric scooter forums. 110 Nm was a more reasonable figure for a 2000 watt motor quoted which would give us 550 newtons of force on the door. OTOH, I'm not an expert in ECV design so ECVs may use gearing to increase available torque while reducing top speed, which would make sense. That would take us back up to 1800 newtons.

* This coefficient of friction is off of some paper I found on the slipping force of shoes on carpet. https://www.jstage.jst.go.jp/article/jte2000/47/2/47_2_53/_pdf
 

s8film40

Well-Known Member
The maximum force that even the torquiest motor could apply to the door would be limited by the coefficient of static friction of the rear driving wheels. At some point, they would start skidding.

So if we know the weight of the ECV + rider + child as 500 pounds and using 0.79 as the coefficient of friction of synthetic rubber on cut pile carpet*, we can estimate that the maximum torque that could be applied by the motor onto the door as 400 pounds of force or 1800 newtons. As per the estimate in the other thread, the impact of the ECV going from 5 mph to a full stop in 100 milliseconds is about 5000 newtons.

It's not insignificant, but I'd still go with the impact force as being the primary cause of the shearing force on the door hinge.

Also note that this motor would need about 360 Nm of torque to achieve 1800 newtons of force on the door. This is about double the torque of a 3000 watt motor I found referenced in a 50 mph racing scooter being discussed over in the electric scooter forums. 110 Nm was a more reasonable figure for a 2000 watt motor quoted which would give us 550 newtons of force on the door. OTOH, I'm not an expert in ECV design so ECVs may use gearing to increase available torque while reducing top speed, which would make sense. That would take us back up to 1800 newtons.

* This coefficient of friction is off of some paper I found on the slipping force of shoes on carpet. https://www.jstage.jst.go.jp/article/jte2000/47/2/47_2_53/_pdf
The monorails haven’t had carpet for quite a while now.
 

Lensman

Well-Known Member
The monorails haven’t had carpet for quite a while now.
Darn it! Need to redo the math now! Lol

I was fooled by the post complaining about that one square of carpet that was stolen and that had to be replaced. :)

Anyway, the coefficient of friction of rubber on various flooring materials seems to vary between 0.6 and 0.8, depending on the roughness/non-slip coating. Being optimistic and going with the upper end of that range gives us the same coefficient of friction as rubber on carpet so it looks like I don't have to redo the math. Whew! Lol
 

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