www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final scene was of the broken-off
rear part of the train which continued down the track to collide with the front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent a reconnect disaster like
that one.

Bob Swinney

that's horrifying. awesome (in the original definition).

http://www.youtube.com/watch?v=cFe0846RgWc

(my second father was a locomotive engineer.)

b.w.


"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied
to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent
a reconnect disaster like
that one.

Bob Swinney

William Wixon wrote:
(top posting fixed)

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied
to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent
a reconnect disaster like
that one.

Bob Swinney



that's horrifying. awesome (in the original definition).

http://www.youtube.com/watch?v=cFe0846RgWc

(my second father was a locomotive engineer.)

b.w.


Also awful (in the original definition). I assume it's the same one I
saw a month or so ago -- I cringed enough when I saw it, don't need to
see it again!!

A search on 'Westinghouse Brakes' should cough up some interesting
tidbits. The pneumatic brake technology used in trains is over 100
years old. It's functional, but it has some severe drawbacks. There
are way better ways* to stop a train now, but inter-railway politics,
inertia and what not** have kept them from being adopted.

* Brake by wire! Just like Toyota***!

** Union-railway politics...

*** Oh, wait...

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

William Wixon wrote:
that's horrifying. awesome (in the original definition).

http://www.youtube.com/watch?v=cFe0846RgWc

(my second father was a locomotive engineer.)

b.w.


This one has edited down to the interesting part:
http://www.youtube.com/watch?v=LYubpuIe3cw&NR=1

Bob

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied
to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent
a reconnect disaster like
that one.

Bob Swinney

I can see the sparks from something on the rearward section's leading car.
May be braking of the front car. But, like you, I thought that when the air
was disconnected, that everything automatically braked. If the rearward
section's cars all braked individually, I don't think it would have been
pushing that front tank car like it was. I was expecting an explosion when
the tanker hit. Some pretty incredible footage, nonetheless. Just like
everything else, there can be malfunctions, or **** poor mechanics.

Steve

Looked like the leading truck on the tanker had rotated
on the track so the wheels were not true - making the
brakes in that truck non-functional.

The train might have been in the push-pull mode - a push
train driving the cars towards the lead engine.

The electrical cables to that car would have been lost -
one would assume it would stop - but perhaps it decoupled
as well...

Would be nice to read the final report.

Martin

Steve B wrote:
"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied
to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent
a reconnect disaster like
that one.

Bob Swinney

I can see the sparks from something on the rearward section's leading car.
May be braking of the front car. But, like you, I thought that when the air
was disconnected, that everything automatically braked. If the rearward
section's cars all braked individually, I don't think it would have been
pushing that front tank car like it was. I was expecting an explosion when
the tanker hit. Some pretty incredible footage, nonetheless. Just like
everything else, there can be malfunctions, or **** poor mechanics.

Steve

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied
to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent
a reconnect disaster like
that one.

Bob Swinney

I am not a railroad person, and I appreciated it. What can it mean?

Steve ;-)

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied
to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent
a reconnect disaster like
that one.

Bob Swinney


My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had it's
own momentum to stop, where the rest of the train had perhaps a mile of cars
to stop, and that is not going to stop quickly!

"Greg O" wrote in message
...

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney


My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Steve

On 2010-03-13, Steve B wrote:

"Greg O" wrote in message
...

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney


My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Electric braking uses motors as generators, and dumps the energy into
big resistors.

Regenerative braking is only available on electrified railroads. It
also uses the motors as generators, but instead of just dumping elergy
into resistors, it returns them into the railroad's power system via
overhead cable.

i

A form of regen braking is available on some "diesel" locos. It consists of a huge bank of
resistors absorbing generated current from the DC traction motors. The resistors are housed in a
pod somewhere on the loco, usu. behind the cab near the top.

Bob Swinney
"Ignoramus4212" wrote in message
...
On 2010-03-13, Steve B wrote:

"Greg O" wrote in message
...

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney


My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Electric braking uses motors as generators, and dumps the energy into
big resistors.

Regenerative braking is only available on electrified railroads. It
also uses the motors as generators, but instead of just dumping elergy
into resistors, it returns them into the railroad's power system via
overhead cable.

i

On 2010-03-13, Robert Swinney wrote:
A form of regen braking is available on some "diesel" locos. It consists of a huge bank of
resistors absorbing generated current from the DC traction motors. The resistors are housed in a
pod somewhere on the loco, usu. behind the cab near the top.

What you are describing is not regenerative braking.

i

Bob Swinney
"Ignoramus4212" wrote in message
...
On 2010-03-13, Steve B wrote:

"Greg O" wrote in message
...

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney


My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Electric braking uses motors as generators, and dumps the energy into
big resistors.

Regenerative braking is only available on electrified railroads. It
also uses the motors as generators, but instead of just dumping elergy
into resistors, it returns them into the railroad's power system via
overhead cable.

i

Robert Swinney wrote:
A form of regen braking is available on some "diesel" locos. It consists of a huge bank of
resistors absorbing generated current from the DC traction motors. The resistors are housed in a
pod somewhere on the loco, usu. behind the cab near the top.
Actually it is most of the roof of main line
locos. The Diesel radiators are the front 1/3 or
so, the back 2/3ds are the braking resistor array.
When you hear a loco pass and there is a loud
humming whir, that is mostly the fans on the
braking resistor grid. Our house is a mile from
the track, and those fans are the first thing I
hear coming, and I can hear them for quite some
time as the train passes.

Jon

"Ignoramus4212" wrote in message
...
On 2010-03-13, Steve B wrote:

"Greg O" wrote in message
...

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with
the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney


My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a
mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Electric braking uses motors as generators, and dumps the energy into
big resistors.

Regenerative braking is only available on electrified railroads. It
also uses the motors as generators, but instead of just dumping elergy
into resistors, it returns them into the railroad's power system via
overhead cable.

i

I watched a specials on trains, and they used Electromotive Diesels to power
electric motors on the wheels. They said during that time they used dynamic
braking.

Steve

Steve sez: "I watched a specials on trains, and they used Electromotive Diesels to power
electric motors on the wheels. They said during that time they used dynamic
braking."

AFAIK, most EMDs still operate that way. There are (were ?) some diesel-over-hydraulic locos but
they are way out of my sphere of knowledge. In an EMD, Diesel engines drive generators which supply
power for traction motors on the axels. "Transmission effect" is done by changing the connectivity
scheme between the generators and traction motors. Large contactors are involved. When undergoing
transition, as it is called, it sounds to a bystander like the engine is shifting gears.

Bob Swinney



"Steve B" wrote in message ...

"Ignoramus4212" wrote in message
...
On 2010-03-13, Steve B wrote:

"Greg O" wrote in message
...

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with
the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney


My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a
mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Electric braking uses motors as generators, and dumps the energy into
big resistors.

Regenerative braking is only available on electrified railroads. It
also uses the motors as generators, but instead of just dumping elergy
into resistors, it returns them into the railroad's power system via
overhead cable.

i


Steve

On 2010-03-13, Steve B wrote:

"Ignoramus4212" wrote in message
...
On 2010-03-13, Steve B wrote:

"Greg O" wrote in message
...

"Robert Swinney" wrote in message
...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with
the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney


My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a
mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Electric braking uses motors as generators, and dumps the energy into
big resistors.

Regenerative braking is only available on electrified railroads. It
also uses the motors as generators, but instead of just dumping elergy
into resistors, it returns them into the railroad's power system via
overhead cable.

i

I watched a specials on trains, and they used Electromotive Diesels to power
electric motors on the wheels. They said during that time they used dynamic
braking.


What they would do with diesel locomotives, is use the traction motors
as generators, and dump energy into big resistor grids. Those were
mushroom shaped things on the roof of the engine, with big fans
cooling them as they would take heat out of the resistors. The beauty
of this method is that there is no wear of brakes or other mechanical
pieces during braking.

Some new railyard switchers, like "Green Goat", work like Toyota Prius
and charge battery banks during braking, instead of just heating
resistors. Probably save the railroad a bundle of money on fuel, as
switchers do not need a lot of continuous power, and they need to
start and stop all the time.

On electrified railroads, the energy from braking can be returned to
power lines to help run other trains.

i

On Mar 13, 8:26*am, "Steve B" wrote:
"Greg O" wrote in message

...





"Robert Swinney" wrote in message
m...
www.tornado1.wmv

Amazing video! *Only a RR person would appreciate this; *but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. *Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney

My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Steve

Brakes on trains operate just like air brakes on trucks. The air holds
the brakes off. Lowering the air pressure begins to apply the brakes.
Each car has it's own compressed air tank holding perhaps 20-30
gallons of air. The air piping on a rr car is about 3/4 inch, as I
recall from many years ago. We lived near a RR track and I walked to
school past a cannery with many cars on the siding. I loved to watch
the old steam engine in operation, shuffeling the cars.

That is an awful lot of air to be released from a single coupling
hose, which is a 2 inch hose. Takes a long time to release the air,
which is why it takes a long time to stop a moving train. All the
stored air has to come out the engine end of the train.

Train watchers will remember occasions where the engineer gets in a
hurry to start a train and begins to pull before the air pressure has
reached the last car. You will hear a moving "BANG" go the entire
length of the train as the couplings are stretched from one car to the
next. If the brakes are all released before pulling, you won't hear a
thing, just see the movement transfer from car to car.

The opposite operation has to take place before a train can stop. The
brake air is bled off as the engine speed is reduced. This has the
effect of closing all the coupling slack on all the train cars. Once
this is done, the engineer can really begin to stop the engine with
it's brakes. and the trains braking will continue to increase,
beginning with the car right behind the engine.

Those train watchers who see the trains in Europe will remember the
couplings are totally different from the US. There they are held
together by a screw-together central coupling and have two spring
loaded bumpers to keep the screw coupling fairly tight. They don't
have the long start an stop time that the US and all trains in the
Americas have.

Hope this helps explain the video a little bit.

Paul

Some good stuff, Paul, but no cigar.

RR air brakes are applied by sensing (brake control) valves in each car. As the engineer calls for
breaking he makes a "brake pipe reduction" in train line air of a graduated amount of psi. The
reduction within the entre brake line is felt simultaneously in each car causing the brake control
valves to move an equivalent amount.
In turn the brake valves release a corresponding amount of air from double ended reservoirs which go
to brake cylinders. To effect more braking, more train line pressure is reduced. Loco engineers
speak of this as so many pounds of braking. One of the down sides of this (Westinghouse AB system)
is that in order to release brakes, the train line pressure must be restored via main air reservoir
in the loco.

Slack action in long trains, particularly exacerbated by hilly terrain is a frequent cause of
drawbars and coupler breakage. Depending on train length and other conditions, going to "Big Hole"
full emergency stop can be a dangerous thing. Literally, the brakes have to be "pumped off" before
a train can be moved.

Bob Swinney






inet.com" wrote in message
...
On Mar 13, 8:26 am, "Steve B" wrote:
"Greg O" wrote in message

...





"Robert Swinney" wrote in message
m...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney

My bet the brakes applied just fine, but the veiw is rearward from the
locomotive, (or set of locos), which stopped right away as it just had
it's own momentum to stop, where the rest of the train had perhaps a mile
of cars to stop, and that is not going to stop quickly!

Don't forget the locomotive has dynamic braking, which is some sort of
electric talk for reducing the power to the motors, which slows them down
electrically, and not with friction.

Steve

Brakes on trains operate just like air brakes on trucks. The air holds
the brakes off. Lowering the air pressure begins to apply the brakes.
Each car has it's own compressed air tank holding perhaps 20-30
gallons of air. The air piping on a rr car is about 3/4 inch, as I
recall from many years ago. We lived near a RR track and I walked to
school past a cannery with many cars on the siding. I loved to watch
the old steam engine in operation, shuffeling the cars.

That is an awful lot of air to be released from a single coupling
hose, which is a 2 inch hose. Takes a long time to release the air,
which is why it takes a long time to stop a moving train. All the
stored air has to come out the engine end of the train.

Train watchers will remember occasions where the engineer gets in a
hurry to start a train and begins to pull before the air pressure has
reached the last car. You will hear a moving "BANG" go the entire
length of the train as the couplings are stretched from one car to the
next. If the brakes are all released before pulling, you won't hear a
thing, just see the movement transfer from car to car.

The opposite operation has to take place before a train can stop. The
brake air is bled off as the engine speed is reduced. This has the
effect of closing all the coupling slack on all the train cars. Once
this is done, the engineer can really begin to stop the engine with
it's brakes. and the trains braking will continue to increase,
beginning with the car right behind the engine.

Those train watchers who see the trains in Europe will remember the
couplings are totally different from the US. There they are held
together by a screw-together central coupling and have two spring
loaded bumpers to keep the screw coupling fairly tight. They don't
have the long start an stop time that the US and all trains in the
Americas have.

Hope this helps explain the video a little bit.

Paul

On Mar 13, 10:31*am, "Robert Swinney" wrote:
Some good stuff, Paul, but no cigar.

RR air brakes are applied by sensing (brake control) valves in each car. *As the engineer calls for
breaking he makes a "brake pipe reduction" in train line air of a graduated amount of psi. *The
reduction within the entre brake line is felt simultaneously in each car causing the brake control
valves to move an equivalent amount.
In turn the brake valves release a corresponding amount of air from double ended reservoirs which go
to brake cylinders. *To effect more braking, more train line pressure is reduced. *Loco engineers
speak of this as so many pounds of braking. *One of the down sides of this (Westinghouse AB system)
is that in order to release brakes, the train line pressure must be restored via main air reservoir
in the loco.

Slack action in long trains, particularly exacerbated by hilly terrain is a frequent cause of
drawbars and coupler breakage. *Depending on train length and other conditions, going to "Big Hole"
full emergency stop can be a dangerous thing. *Literally, the brakes have to be "pumped off" before
a train can be moved.

Bob Swinney

inet.com" wrote in message

...
On Mar 13, 8:26 am, "Steve B" wrote:



"Greg O" wrote in message

...

"Robert Swinney" wrote in message
m...
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final
scene was of the broken-off
rear part of the train which continued down the track to collide with the
front half. Normally,
when a train breaks in two like that one, automatic air brakes are
applied to both portions.
Theoretically, both halves should come to full "emergency stop" to
prevent a reconnect disaster like
that one.

Bob Swinney

Thanks, Bob.
That does explain a lot of what I have observed.

The older son of my sister-in-law's neighbor is a train engineer for
the local railroad. He went through many months of class room and on-
job training before he could drive a train. A lot more complicated
than shown in the movies!

Paul

Robert Swinney wrote:
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final scene was of the broken-off
rear part of the train which continued down the track to collide with the front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent a reconnect disaster like
that one.
Air brakes don't work that well when the wheels
are off the track! If you look down below the
tank car, the sparks seem to indicate at least
several cars of the rear portion have derailed.

Jon

"Jon Elson" wrote in message
...
Robert Swinney wrote:
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final scene was of the broken-off
rear part of the train which continued down the track to collide with the front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent a reconnect disaster
like
that one.
Air brakes don't work that well when the wheels
are off the track! If you look down below the
tank car, the sparks seem to indicate at least
several cars of the rear portion have derailed.

Jon

Jon sez: "Air brakes don't work that well when the wheels
are off the track! If you look down below the
tank car, the sparks seem to indicate at least
several cars of the rear portion have derailed."

Right Jon. And they don't work all that well with everything in its place, either. I've heard it
said that "a mile long freight train, at speed, can't stop in it's own length"

Bob Swinney

"Jon Elson" wrote in message
...
Robert Swinney wrote:
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final scene was of the broken-off
rear part of the train which continued down the track to collide with the front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent a reconnect disaster
like
that one.

Jon

The brakes are to help the train stopped when stopped. Not roll down a hill.
The brakes are not all that good to stop a train they just can't handle the
energy delivered upon demand.

That is why a number of people get run over in crossings - thinking the train
can stop. They will stop and back up.

Trains often have rear end pusher trains if on grades. The lead train
electronically controls it.

I know a SP train master and see him most days.

Martin

Robert Swinney wrote:
Jon sez: "Air brakes don't work that well when the wheels
are off the track! If you look down below the
tank car, the sparks seem to indicate at least
several cars of the rear portion have derailed."

Right Jon. And they don't work all that well with everything in its place, either. I've heard it
said that "a mile long freight train, at speed, can't stop in it's own length"

Bob Swinney

"Jon Elson" wrote in message
...
Robert Swinney wrote:
www.tornado1.wmv

Amazing video! Only a RR person would appreciate this; but the final scene was of the broken-off
rear part of the train which continued down the track to collide with the front half. Normally,
when a train breaks in two like that one, automatic air brakes are applied to both portions.
Theoretically, both halves should come to full "emergency stop" to prevent a reconnect disaster
like
that one.

Jon