Thanks for the explanation. The hand brakes are to be set on the first five
cars, or is it 10? if the train is to be parked. This insures that the tran
won't roll. If your employees are lazy, then sometimes this doesn't happen
and cars roll away.
Keith
_____
From: cpsig@xxxxxxxxxxxxxxx [mailto:cpsig@xxxxxxxxxxxxxxx] ;
Sent: Thursday, May 22, 2014 8:43 PM
To: cpsig@xxxxxxxxxxxxxxx
Subject: Re: [cpsig] Re: Fw: Central Maine & Quebec CEO: 'We'll have to
prove ourselves'
If you're dealing with road air brakes, then yes, you can be forgiven for
thinking that way. On those air brakes, air pressure keeps the brake pads
away from the disc/drum, fighting against a spring wanting to apply the
brakes.
However on railway air brakes, you have a reservoir of air pressure that
applies brake shoes to the wheels. The flow of that air pressure is
controlled by the triple valve, and yes, the drop in air pressure allows the
triple valve to send air pressure from the reservoir to the cylinder
applying the brakes.
With that in mind, without an air compressor feeding air into the reservoir,
leakage throughout the system (and this would very likely come from a few
places, like the EOT (these generate their power from a small nozzle
stealing some air from the train line to spin a turbine wheel and generate
electricity to charge the battery and run the electronics), imperfect
couplings along the hundred plus joints in a typical oil train of today, and
all those other small bits which allow air to escape, and soon enough, there
is not enough air pressure in the reservoirs to keep the pressure on the
brake shoes. That's why you don't need to have air hooked up to
free-rolling cars going over a hump, and why the train would have rolled
away if am insufficient number of handbrakes were set. In level trackage,
10 cars may be enough. On a grade, with loaded cars, obviously not enough.
Jon
On May 22, 2014, at 6:51 PM, "kvrailway@xxxxxxx [cpsig]"
<cpsig@xxxxxxxxxxxxxxx> wrote:
As an old carman, there is one aspect here that I do not understand. I
don't pretend to have followed the official, publically-available
information in great detail.
However, a great fuss is being made about the engine shut-down affecting the
brakes. If the air brakes were applied, I don't see how an engine shut down
would
make a difference to anything. Something must have been done by somebody to
cause those train brakes to release. Either that, or enough cars had
leaking brake
cylinders to cause what in effect would be an undesired brake release.
Properly functioning air brakes on those cars should have been able to
sustain a brake
application for days or even weeks or even longer. The thing is:
'maintaining air' means that a lot of people don't know what they are
talking about. A sudden
lost of air should have put the train brakes into emergency application. A
slow loss of air from the train line should have meant a tighter brake
application. An
engine shut down means that the retaining valve feature on the locomotive
would cease to sustain the train-line pressure at the point where the
engineer left
it. A loss of the pressure maintaining function doesn't lead to a brake
release, if the brakes on the train are functioning properly. If the
engineer only made a minimum
brake reduction, it may not have been enough to set up every car. But that
is the only explanation I can see beyond somebody releasing the brakes or
doing something
to cause a ripple in the train line brake pressure ... just enough to fool
the portions into a release. I've seen that happen. Otherwise, if nobody
touched anything
they shouldn't have, there must have been a lot of cars with brake cylinders
suffering some degree of blow-by so that they weren't holding a set-up
properly.
This is an issue which will probably become more of an issue with the
passage of time, because so far as I know, there are no set regulations for
how long an
individual car has to sustain an air brake application. Neither are cars
being inspected for such things the way they used to be.
Again, I stand to be enlightened.
Joe Smuin
From: mailto:cpsig@xxxxxxxxxxxxxxx ;
Sent: Thursday, May 22, 2014 1:20 PM
To: cpsig@xxxxxxxxxxxxxxx
Subject: [cpsig] Re: Fw: Central Maine & Quebec CEO: 'We'll have to prove
ourselves'
Here is what I understand happened:
The train was left on the main line NOT in a siding because it was blocked
by empties for the mill in town. SOP (Standard Operating Practice). Engineer
applied 11 hand brakes, one more than the 10 required by MM&A. Firemen cut
off fuel (this is done outside, on the ground, not in the cab) again SOP for
fighting fires. MOW person was advised by firemen they had shut down unit.
MOW man advised RTC. One hour and 5 minutes later the train ran away. It
would appear the RTC failed to take action to get unit(s) restarted in order
to maintain air. Maybe he was unaware of the seriousness of the situation.
Maybe he was not advised of shutdown of other units although again, this was
SOP and he SHOULD have known. I am guessing this is why he was arrested. In
any event he had a key role as the person in charge of things at the time.
Manage arrested as he is also responsible for matters. Not sure why the
President was not arrested too at that rate. CEO Burkhardt was in USA.
The real fault lies in Ottawa. BTC inspectors used to rule over safety and
issue fines if in violation. Unfortunately, we don't have the Government of
Canada anymore. We now have the Harper government which lets railways and
others police themselves. TC inspectors cannot even issue fines.
What happened is what happens in all tragic disasters Titanic etc. Not any
one thing went wrong, not any one person to blame. It comes about with a
number of things coming together at the wrong time. Sad, very sad.
Raymond
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