Spectacular derailment in Western Australia.

[miyakoji]

We would have to know the braking effort too, but anyway the outcome of the event tells us that it was not sufficient to hold the train on the grade.  Makes me wish I could remember physics class better 🙂, I did enjoy it.  Would 1 in 66 be 15 permil?

[Sheffie]

The calculation for weight is as follows.

A 1 in 66 gradient is an actual angle of asin(1/66) or 0.868 degrees. (Assuming I understand railway gradient correctly, as the ratio of increase in height to distance along the rail, not horizontal distance.)

The component of the train's weight acting down the slope would be sin(0.868), or 1/66 again.

[katoftw]

100 handbrakes applied in under 60 minutes. Folks! Tell him he's dreaming.

[cteno4]

Mark is the one who knows, he’s done this stuff!

 

jeff

[katoftw]

Mark also stated 100 in 60 mins or less was unlikely. And he would know, as jeff informs.

Edited March 21, 2019 by katoftw

[cteno4]

Lots of unknowns here as well so it’s doing a lot of assumption to try to get any answer, and thus likely flawed.

 

jeff

[ben_issacs]

steffie, 

Train weight 42,500 tons, grade 1:66, divide 42,500 by 66, answer about 650 tons, which is the gravitational force pulling the train down the grade.

And this is the force which the handbrakes must resist to hold the train.

Anyrate, how many handbrakes were applied, and we can only speculate on this number, there weren't enough to hold the train.

We must await the full report for further details.

Regards, 

Bill, 

Melbourne.

 

[cteno4]

Also the combined frictional force of rolling resistance would add to brake side of the equation. Again unknowns.

 

jeff

[ben_issacs]

Folks, 

From Mark's shot of an iron ore car, they have roller bearing axle boxes, so rolling friction would be pretty low.

Regards, 

Bill, 

Melbourne.

 

[ben_issacs]

Miyakoji,

To convert 1:60 into per cent or per mille, , just divide  100 or 1000 by 60.

Regards, 

Bill, 

Melbourne.

 

 

[ben_issacs]

Folks, 

More info is now available on the ATSB web site, giving details of the action that the driver took, amongst other things,

But the final report looks to be still a long way off!

Regards, 

Bill, 

Melbourne.

 

[Takahama Trainwatcher]

162 km/h!