Locomotive Air Hoses
FredDunn1
I have noticed on Amtrak locomotives, (and freight locomotives as well)
that in addition to the main brake air hose there are three smaller air
hoses. On Amtrak multiple locomotive configurations, the four hoses (main
brake air plus the three others) are coupled between the locomotives. On
the passenger cars behind the locomotives, the main brake hose and one of
the other three smaller hoses is coupled from car to car. On Amtrak F40s,
these three hoses are labled AP, ACT, and MR. The MR hose appears to be
slightly larger than the other two, but not nearly as large as the main
brake hose. I think it is the MR hose that continues to be coupled
between the passenger cars. I assume that these hoses have something to
do with the multiple unit control system, and maybe backup braking, but I
am just guessing. Can anyone fill me in as to the function of each of
these air hoses?
Thanks, fred...@aol.com
Richard Alvarez
FredDunn1 at America Online, Inc. -
Many years ago, I asked about those hoses, to Malcom (Mac) Gaddis,
who I think was chief electrical engineer of motive power at Southern
Pacific. Below, I describe the diagram that he drew in my note-book.
Left side: sand reverse
Next: ind release (I presume the independent brake)
Next: ind appl
Next: main reservoir
Next, and lower: signal
Center: coupler
Next, slightly right of center, lower: brake pipe (large)
Next, on the higher level with the left 4 hoses: main reservoir
Next: ind appl
Next: ind release
Right side: sand forward
At Sacramento, California, in the collection of historic cars and
trains near the rail road museum, I copied the following information
from the hoses on SP 137 dynamometer car. The hoses were labeled "1"
through "4" on each side, with "1" closest to the center on each side.
Nearby, were painted the numbers and the following labels.
1: main res
2: actuating
3: appln & release
4: sand (no mention of forward and reverse)
Slightly left of the center, was what I presume to be the steam line
for heating.
Slightly right of center, was the hose for the large train brake
pipe.
Near the center, was another air hose which hol...@junction.net
(John Holmes) described as follows, on Usenet, in answer to my question,
on Thu Feb 15 21:54:01 1996: <<Probably the signal pipe. The on board
conductor or snow plow foreman would operate a valve inside the car/plow
that would deplete the air in the signal pipe and cause a whistle to
sound in the operating locomotive. Different combinations to instruct
the engineer to "Stop at next station / Proceed / Back etc. That
function is nullified by the use of radios. Some engines remain equipped
with a signal pipe, sometimes incorrectly referred to as the "Snow plow
feature". All it does now is supply straight air to operate equipment
ie: air dump cars, spreader wings etc.>>
On the car end near the left side, higher, were several electrical
receptacles which I did not investigate. I suppose that one was the MU
connector for Diesel-electric locomotives. That dynamometer car
presumably was built for steam locomotives, but inside the car I saw
indicator lights which seemed to be for Diesel-electric locomotives.
Most of my information is several years old. I don't know about
Amtrak locomotives, or the push-pull operation as on Caltrain on the San
Francisco Peninsula. If anybody has information on that, please post!
Dick Alvarez
alv...@best.com
Jason Crupper
In article <4ou1f7$j...@newsbf02.news.aol.com>, fred...@aol.com
Ok, on freight trains, there is only one way to realease the brakes- full
release. If you set too much brakes, tough luck. The only way to slow
your decelration rate is to release the brakes completely, and set them
up again. But if you do this too much, you can use up all the air
pressure on a car. This is called pissing off the air.
Now to clarify, the three hoses you see besides the main brake hose, are
as follows:
ACT- Actuating: Locomotives have a brake control valve on them just like
a freight car, on top of their independent brakes. When you make a
reduction in the brake pipe, the brakes start to set up on the
locomotive. The Actuating valve is part of the independent brake valve.
You push down. This prevents any air pressure from building up on the
locomotive consist from a Train brake application. That is the ACT hose
between the units. The pressure in this hose is either 0 or 90 psi.
APP- Application and release: This allows all units in a consist to have
their independent brakes set and released from a single independent brake
valve. Units=engines. The independent brakes are the brakes on the
engines only. They are independent of the train. The air pressure in this
hose is anywhere from 0 to 45 PSI.
MR- Main Reservoir: This hose ties all of the Main Air Reservoirs of all
the locomotives in a consist together. This is nice, say if an engine
dies, it's brakes are still operable because the other units keep it
pupmed up. This hose is also hooked up to passenger cars so that they
also have brake systems pumped up all the time, there fore allowing a
graduated release of the brakes, unlike a freight train. If you are
slowing down too fast, you can reduce braking a little bit. The air
pressure in this hose is almost always 130 PSI.
Hope this helps. If you have any more questions feel free to email me...
Jason Crupper
GP60M
Sirsonic
The MR is most likely the Main Resevour.
Expect a train on ANY track, at ANY time
in ANY direction.
Sirs...@aol.com M.P. 20.05 Conrail Lehigh Line
Co-Founder of RAVE
"You're by the door with a good one!"