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ben_issacs

Spectacular derailment in Western Australia.

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marknewton
On 11/28/2018 at 6:48 PM, ben_issacs said:

If, on that train weight, we knock off the 620 tons for the four locos, we then get just on 160 tons per wagon.

130 tons for the load and 30 tons for the wagon, is that reasonable?

 

 

 

From memory the modern “GoLynx” wagons weigh about 25 tonnes. But 160 tonnes per wagon is right.

 

Mark.

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marknewton
9 hours ago, Ochanomizu said:

Perhaps the ECP brake can be upgraded to require manual release in future?

 

That’s one proposal being discussed at the moment.

 

Mark.

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marknewton
6 hours ago, ben_issacs said:

Using Mark's train weight and grade figures. on the 1:60 grade with a train of 43,620 tons, the component of the gravitational force parallel to the track , the 1:60 grade, is 727 tons.

This is the force tending to pull the train down the grade.

I've assumed that the four locos had a total weight of 600 tons.

Using the Static Co-efficient of Friction for steel wheel on steel rails of 0.78, it requires a force of 468 tons to move the locos against their brakes, less than the 727 ton force calculated above, so as Mark wrote, the independent loco brakes could not hold the train if all the train brakes went off.

Once the train starts to move the Co-efficent of Friction becomes a Sliding Co-efficent, which is much less than the Static one, so the train keeps on going.

With the loco wheels locked, they must have developed considerable flats at the place of derailment.

 

Had they remained locked then they would have had enormous flats, but I doubt they did. Even on the very best maintained locos the independent brake will leak off fairly quickly. It doesn’t take much to get the wheels turning even against the brake. As I noted earlier, I don’t know if the driver applied the independent or not before leaving the cab, but even if he did, I’d be very surprised if they stayed applied for the duration of the runaway. Once the train started moving and the wheels started to turn even a bit, the wheels and shoes would heat up very quickly and the braking effort would fall away. More so once the shoes stated to be worn away by the wheels.

 

Mark.

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ben_issacs

Mark, 

Fair comment about loco wheels and independent brakes.

If the wheels were turning, they would be turning the traction motors.

Would these run as gennys and feed current back into the electrical system, as a regen. brake, which wouldn't do much to slow the train down.

Regards, 

Bill,

Melbourne.

 

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kvp
5 hours ago, ben_issacs said:

Would these run as gennys and feed current back into the electrical system, as a regen. brake, which wouldn't do much to slow the train down.

Electrical motor brakes are normally very good at slowing a train down, especially in a ballastless cross connected or shorted configuration. (shorted means the motor contacts are shorted together for maximal emergency brake currents). I'm not sure if these locos were equipped with them at all and with such a huge train weight, they wouldn't really matter. Also not effective when the throttle and/or the reversing switch is in idle position, which effectively disconnects the traction motors on most diesels. The same is true for any disk brakes as they would get worn pretty quickly if they could'n keep the wheels locked.

 

Imho the only sure ways to keep a freight train like this stopped is to use the air brakes on all cars or turn the handbrakes on at least half of them or add lots of brake shoes under the wheels. Imho even a standard buffer clamped onto the rails couldn't keep them from rolling down the slope.

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ben_issacs

KVP,

Thanks for your comments on traction motors running as genneys.  

Most useful for me, as to modern elec. traction stuff, I'm disconnected!

Regards, 

Bill, 

Melbourne.

 

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ben_issacs

Mark, 

Many thanks for that info. 

The cab ride shots were of interest, North Coast Line I assume?

When the wagons are tippled, do the air and ECP lines disconnect?

Re-connected after progress through the tippler.

Regards, 

Bill, 

Melbourne.

 

 

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kvp
5 hours ago, ben_issacs said:

When the wagons are tippled, do the air and ECP lines disconnect?

On the linked pictures the lines are mounted to the couplers. One coupler is rotatry, the other is not, so two connected couplers always rotate together. This means the coupled lines could stay connected as long as the couplers stay together. Any flexibility issues must be handled on the side of the rotary coupler. Afaik the cars must rotate around the axis of the couplers, so the car movement around them is minimal.

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ben_issacs

KVP'

Thanks for that info.

Yes, of course, the couplers stay coupled as do the air and ECP lines, but the waggon rotates independently.

Regards, 

Bill,

Melbourne.

 

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ben_issacs

Folks,

The official investigation into this runaway is being conducted by the Australian Transport Safety Bureau (ATSB).

Looking at the ATSB web site, all that they say there is 'Collecting evidence'. 

The final report won't be issued until about the middle of next year. 

The ATSB reports on incidents involving marine, air and rail, and it's interesting to Googly up their web site, just put in ATSB.

Over the past three months there have been three railway runaways in various parts of Australia, the W.A. one was the most serious of these, all are under investigation, so their investigators would be pretty busy.

Regards, 

Bill, 

Melbourne.

 

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Kiha66

Interesting.  Sounds like the engineer did everything he could applying all those handbrakes.  I wonder how many he got done before the train began to move and how many would have been needed to keep the train secured?

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miyakoji
20 hours ago, Kiha66 said:

I wonder how many he got done before the train began to move and how many would have been needed to keep the train secured?

I was thinking this too.  Too bad about the work crew applying brakes on the wrong train, maybe that would have been enough.  In the preliminary report that Mark linked, it says the engineer of a stopped train reported to control when the runaway passed with 'brakes dragging.'  Does that mean the wheels were turning against fully applied brakes, or that the wheels were locked and skidding on the track?

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ben_issacs

Folks, 

The preliminary ATSB (Australian Transport Safety Board) report on this incident has just been released.

Too long for here, go to ATSB and then to Railway, then to Derailment Western Australia.

All trains on the double track  line were stopped by train control, who requested a maintenance crew to go to the stalled train and apply as many handbrakes as they could, the driver was walking back along the train also applying hand brakes.

But, it seems that the maintenance crew went to the one of the other stopped trains and started to apply the handbrakes on it!

The two leading locos and one car negotiated the derailment point safely and came to a halt further on, the rest of the front half of the train and the two middle locos all derailed, along with most of the rear train half, twenty cars of this section alone remained on the track.

This is a preliminary report only, further details yet to come.

Regards, 

Bill, 

Melbourne.

 

 

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ben_issacs

Folks, 

I see that Mark has given the url for the ATSB report. 

How many of the handbrakes could the driver have applied?

Each hopper looks to be about 13 metres long.

Say the driver is walking at about 2 miles an hour,  walking on the track side in the dark, and stopping to apply the handbrake on each car.

Two mph is three thousand two hundred metres an hour, which means he could have covered about 250  cars in that hour, assuming that he started walking as soon as the train stopped, unlikely , as he would be reporting to control, and awaiting instructions.

So, in theory, he should have at least got to the mid-train locos.

One of the stopped train drivers reported that the runaway passed his train with the brakes 'dragging' so some of the cars must have had their handbrakes on, but obviously not sufficient to stop the runaway!

We await further information.

Regards,

Bill, 

Melbourne.  

 

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katoftw

You failed to calculate and include the time it takes to actually apply the hand brakes manually.

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ben_issacs

katofw,

My 2 mph walking pace in theory should allow for brake application time at each car, but still could be optimistic.

The normal marching pace in the Australian Army, when I was in it, was 100 yards a minute, on good roads, giving 6,000 yards an hour, which is a bit over 3  mph.

I've knocked the 3 mph down to 2 to allow for rough walking path, bad light and the need to stop at each car to apply the handbrake

This might still be too high!.

Without actually trying this out, one can only make an assumption.

I still think that at the most about 100 cars could have had their handbrakes applied by the driver, in the hour.

And he wouldn't have had a full hour, there'd be a bit of time at the start when he was talking to control, so his walking time could have been 55 minutes or less.

No doubt the final ATSB Report will elucidate this matter.

One question, double track, is this right or left hand running?

Most public lines in Australia are left hand running, but the iron ore lines could be r.h.

Regards, 

Bill, 

Melbourne.

 

 

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katoftw

60 "AT MOST" in one hour.  The handbrakes require about 10-12 half turns of the wheel.  The chains and levers attached offer high resistance.  And the wheels are either up a ladder or under the body of the freight car making access slow.  All these issues means you will not apply a handbrake in 10-15 seconds as per you calculations.  More like 30-45 seconds.

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cteno4

Also walking on the ballast shoulder which is not easy walking or on the dirt shoulder but then lots of ins and outs and crossing ballast.

 

jeff

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miyakoji
4 hours ago, ben_issacs said:

I still think that at the most about 100 cars could have had their handbrakes applied by the driver, in the hour.

 

I was thinking this too, but after trying to imagine it I think it may be too optimistic.  Imagine walking the ballast as Jeff says, climbing a car, turning the wheel (spinning then cranking, maybe all cranking 🙂 ), climbing down, walking to the next car.  I wouldn't be surprised if it averages out to a few minutes per car.  He was complying with a rule, not working under the expectation of the train rolling away.  I bet he only got a few dozen.  There were no injuries or fatalities in this, so there's something to be thankful for.

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marknewton

BHP Golynx ore wagon of the type involved in the runaway. Note position of handbrake wheel. Also note that with this type of handbrake, if you try to wind it on too quickly, the ratchet doesn't engage and the handbrake doesn't apply.

 

Mark.

 

040815_165436.jpg

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marknewton
On 3/12/2019 at 7:46 PM, Kiha66 said:

Sounds like the engineer did everything he could applying all those handbrakes. 

 

If he'd made an emergency application of the conventional automatic air brake as required by BHP's OSPs then the train wouldn't have run away in the first place. I don't know how many handbrakes you'd need to hold a 42000 ton train on a falling grade like that, but obviously he needed more than he managed to apply.

 

All the best,

 

Mark.

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marknewton
On 3/13/2019 at 4:27 PM, miyakoji said:

I was thinking this too.  Too bad about the work crew applying brakes on the wrong train, maybe that would have been enough.  In the preliminary report that Mark linked, it says the engineer of a stopped train reported to control when the runaway passed with 'brakes dragging.'  Does that mean the wheels were turning against fully applied brakes, or that the wheels were locked and skidding on the track?

 

Wheels turning against the brake shoes.

 

Mark.

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marknewton
15 hours ago, ben_issacs said:

I still think that at the most about 100 cars could have had their handbrakes applied by the driver, in the hour.

 

I'd say that's highly unlikely. Walking on ballast is slow, awkward and uncomfortable. Try to do it for any great distance and you're buggered very quickly. I'd suggest the driver would have chosen to walk on the access road instead. That still means he'd have to climb on the ballast shoulder to access the handbrake on each wagon, so that will slow him down as well. Then there's the cumulative effect of winding each handbrake on. The further he went and the more he applied the more fatigued he'd have become. And that's in addition to whatever fatigue he was already feeling at that time of the morning. No doubt the final report will have the answer, but I'd be surprised if he managed to apply half that number.

 

All the best,

 

Mark.

Edited by marknewton
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ben_issacs

Folks,

Mark made some good points about how the driver could have walked the train

Probably not on the ballast, the wagon overhangs would make this awkward, there would likely be a bit of more or less flat ground outside the ballast shoulder which could be walkable.

The shot of the ore wagon was useful in showing the position of the handbrake wheel. reasonably accessibleble, but one still has to climb up and down the ballast shoulder, which for 40 t axle load, would be fairly high.

Then there is the fatigue problem, and some of the brake rigging would be tight, wheel hard to turn.

I originally thought that he could do 4 cars a minute, Mark reckons 2, which I think is more likely, so at a maximum, there could be about 100 cars with their hand brakes applied.

Now, would 100 hand braked cars hold the train on the 1:66 grade?

My original calcs, said they would, but I'm not convinced that I'm using the correct approach.

Come on, there must be someone out there who could work this out properly. 

We know the train weight, we know the gradient, so we should be able to work out what component of this weight is pulling the train down the gradient, then all we have to do is to work out whether this force is greater or less than the force required to move the 100 or whatever cars with their brakes on.

Regards, 

Bill, 

Melbourne.

 

 

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