Thank you guys so far for all your reply's.
As Broke Sheave has pointed out, I'm starting to get the hint that the answer to my question might not be easy, as there are too many factors at play.
@Johnny...good point about the CWT safety stops, as this single feature would likely take the wind out of the rapid ascend by stopping the counterweights before the cabin crashes into the ceiling, but I'm getting the sense that most shafts are not equipped with the extra space needed?
I think that for most part, I have enough partial reply's to be able to piece together that this sequence could occur (maybe in the past) under certain circumstances, as per Broke Sheave's quote:
And yes. In my 35 years I have witnessed the scenario you describe. An older open loop control from the 60's. Not seen it on any of the newer controls because of built in safety redundancy. There are just so many possibilitys to your scenario, I'm sure everyone here on this board could dream of this happening if X,Y,Z happened on Control type Q...
@Broken sheave, I know that you said you are not likely to post again, but if you do I would like to ask you if you could confirm, that scenario you said to have witnessed also included the shaft ceiling caving in and spilling out the machinery down into the shaft (as per my scenario), since this is probably the only piece of puzzle that I'm still not sure about?
Postal has pointed out earlier, that in the link that I have provided, the fall of the drum machinery was most likely due to the use of timber in the overhead structure (yes I'm aware that the cab has never hit the ceiling in that case, but that is one of very few cases I could find, which involves machinery falling on top of the cab)....
At this point I'm still unsure, if a concrete ceiling of later construction could fail structurally, had it sustained a hard enough hit hit from the ascending cab?
Again, I very much appreciate all of your answers you guys provided to me so far...
