Originally Posted by
megan
The question to ask with the BHP train is what happened with the dead man system.
There is no dead-man system as such on freight trains in Australia. Suburbans, yes, but not freight. What we have is usually called a Vigilance system (or an Alerter if you use the American terminology). This is a button that you have to press every 30-45 seconds, or the brakes apply. However, to save Driver's having to press it every 30 seconds when the train is stopped, it is inhibited when you have more than 200Kpa in the Independent (locomotive) brakes. Which you always have applied when you stop anywhere. So no Vigo to stop it.
Originally Posted by Matt48
You just have to marvel at how the brakes released themselves, how the throttles were nearly fully opened and why the driver couldn't have reboarded the train, as it took off like a tired snail. It covered 120 KM in about 50 Mins, at an average speed of 110kmh.
It was on a descending 1:66 grade - the steepest on their network. You don't need power to get moving - and get moving bloody quickly - on a grade like that, with a train like that. I work trains on 1:50 descending grades, and if you release the brakes you'll get upto well over 100kph in the length of your train no worries at all - all on a 1.15* descent angle, less than half what an airliner achieves from TOD with idle thrust...And the railway rumour mill has the datalogger showing speeds
well in excess of the average reported. FWIW, thee is one hill I come over the top of, and I can coast, without touching the throttle, for
55km at track speed, then apply power over one hill for 4km and roll another 12km.
Originally Posted by megan
The Devonport train was remotely controlled - no onboard driver.
Only insofar as on the leading locomotive. The driver was doing what is known as RCS, remote controlled shunting, whereby he has a control unit on a harness around his neck, and uses that to move the train. IT is
supposed to be failsafe if it loses comms with the loco, or vice versa, the brakes are supposed to come on. I'm keen to see why they didn't.
What is unusual is BHP utilises Automatic Train Protection on their network, to facilitate Driver-Only Operation. ATP has safeguards against rollaway, overspeed and passing a signal at stop. Why the Rollaway and Overspeed protections failed is interesting. Depending how their braking system is configured would depend on whether or not it would function effectively with an ECP braking fault. Traditional railway airbrakes work by pressurizing the Brake Pipe, then reducing this pressure to apply the brakes. This makes if fail-safe, in that a brake command by yours truly, or a snapped train, results in the brakes coming on. BHP, like all the mines up there now, use Electronically Controlled Pneumatic brakes, where the brake pipe does
not reduce to apply the brakes, rather, an electronic signal is transmitted and a manifold on each ore wagon applies the brakes to the %-age commanded by the driver. If ATP is configured to work exclusively with ECP when ECP is active it would not function to command a pneumatic emergency brake.
If an ECP cable separates, this will trigger an ECP Emergency brake - 120% of braking capacity - but it will not reduce Brake Pipe Pressure. The potential problem with this, is the ECP cars *not* talking to the locomotive now start a timer, and after a pre-configured delay (usually an hour, depends on the operator), revert to standard pneumatic braking. IF the Brake Pipe is still charged, the brakes will release in pneumatic on those wagons, and you are then relying on the front X number of wagons to try to hold the train stationary. IF he was 50 back fixing the cable, only 50 cars with brakes isn't likely enough to hold a full train on a grade like that. Without knowing BHP's procedures, I'd think they would require the Driver command a full pneumatic emergency brake application before getting off the loco to guard against a fault like this - which if forgotten could lead to such a scenario as they had.
Originally Posted by 2016parks
Let's see ... single driver ... autopilot ... loss of control ... gee, uh, those topics wouldn't be relevant to the topic of aviation, or to any known aviation accident, now would they
Add in fatigue, systems knowledge, SOP compliance and a relatively laissez faire approach from some operators and the regulator and you can begin to draw some parallels between the two.