Remote control locomotive operators. Are they required to whistle (one short) at certain times/places/people when they are working in the yards?
Air for the brakes. Figure there are air tanks on the engine. Figure there is a compressor to operate said air. Where does said air come from to get into tanks?
Grain train. Loaded. Going past slowly. Can you smell the soybeans loaded inside or do I just have a very vivid imagination? (twice!)
Not sure on the remote whistles. With radio com nowadays whistles in yards seems to have gone the way of the dino.
Air is all around you. The compressor sucks it in either through the engines air filter or its own filter. There are basically 2 kinds of air compressors. The piston/ reed valve type and a rotary screw type.
I imagine you are smelling the old spilled grain that has been spilled and rotting.
Pete
Probably pulled into the compressor via (IIRC) inertial filters. My question: how does the operator know how much air is in the tanks? Are there gauges mounted outside where they can be seen or is some kind of telemetry used to relay this info to the ‘belt pack’?
There might be some spillage on the tops of the cars.
R.C.L. operations may require the sounding of a diesel horn in some locations, but it’s not a universal requirement.
In most diesel locomotives air from inside the engine room is drawn through a fine mesh filter and piped into the first stage piston compressor. From there it moves to the second stage piston compressor. Lastly the compressed gas is then piped into the main reservoirs. Main reservoir pressure is regulated to fluctuate between 120 and 130 psi., possibly a little higher for Amtrak.
As covered hoppers are filled, sometimes a little grain spills over the sides and gets caught in various crevices. When exposed to the elements the grain rots. That’s maybe what you’re smelling.
An open top wood chip car typically has dozens of pockets where blown product accumulates. Whether loaded or empty they can smell quite nice. By contrast any car assigned to a cotton seeds pool will have a particularly pungent odor.
Perfect! I now have all 3 of my questions answered.
We have a bridge (Salt Creek) at the throat of the yard and I keep hearing an occasional one short whistle near that bridge. Today there was a yard engine and the RCO was standing on the side of the engine. Thought there might be a connection.
Was watching a coal train put out BO cars back and forth in front of us. Got to thinking about the air brakes and well, you know the rest.
Grain trains go by and once in awhile I would get a whiff of soybeans. They process them here at ADM, so know that smell. But also know where you can smell them in town and it isn’t where we were parked. The only thing I could tie it to was the passing grain cars. Wasn’t very strong, but definitely smelled like soybeans.
Thanks for all the answers. Now back to watching and thinking.
Hi, SJ! I’m actually writing this from a sitting position, in my own chair!
No, the horn isn’t a requirement for remote units just because they’re remotes. However, the operator is expected to sound it in cases where it’s supposed to be, such as at crossings, and to provide a warning for employees on or near the tracks. On our yard’s remote, the bell is programmed to ring whenever the independent brake is released, serving as a warning for impending movement.
Not sure how remote operators know how much air they have. I know that some have been surprised at how much less braking power they have as opposed to what they expected, but that’s usually a function of something other than air supply.
I would say that (reasonably) fresh grain sitting on the car’s roof, or perhaps the discharge outlet racks is what you’re smelling, especially if it happens only on occasion. The lading that stays too long does not smell pleasant. My position in relation to the roofs of the cars makes me wonder about the lack of cleanliness, though it shouldn’t get into the stuff that actually gets inside the car and is considered payload.
At times we’ll use one short on the horn in response to a hand signal from a trainman wanting to go into the red zone. Red zone for us, establish 3-step protection (do I have that term right?) for others.
Radios may be almost universal, but there are times when hand signals are better.
Jeff
It is “three step”. I’ve also heard of “in between.”
We routinely use hand signals. Part of it is for show (albeit correct), part of it is to hold down the chatter, which the FRA mentioned to us once on a visit. Were it not for calling switches (as discussed in another thread) we could do all of our runarounds on hand signals.
The only time the RCO has to sound the horn is at a public crossing. The RCLs, however, are programmed to ring the bell a few times, before starting to move. With ours, the bell rings when you change the speed from stop. It can get annoying though, listening to the bell ring every 2 minutes during switching. Local rules may require using the horn at other times.
Air gets sucked into the compressor from outside, and forced into the air tanks. Carl, our RC control units have a readout that display the brake pipe pressure (allegedly). Using the air from the RC units is usually far more trouble then it’s worth, so most often, we just work without.
Yes. Yes. Yes. You can also smell cocoa beans, lumber, mill turnings, coke, trash, sewer sludge, etc.
Nick
hey sis the short answers are that yes rco are required to whistle signals like regular engineers but only for the perpose intended, First rule is when a train or engine is starting to move in yards or in switching it is to ring the bell to let others know its about to move, if crossing the bridge yes they should whistle off.
As far as the compressor its abeen covered and as for the beans and corn or barley or wheat yes and no some are easier to smell than others
From other answers in this thread and elsewhere, we should know that the air compressor output pressure typically ranges rom 90 PSI = Pounds per Square Inch to 140 PSI = 6 to 10 ‘atmospheres’ = times normal atmospheric pressure of 14.7 PSI, and hence the density of the output air is similarly 6 to 10 times that of the ‘free air’ around us.
Now, that got me to wondering about the output volume or rating of the locomtoive air compressors in CFM = Cubic Feet per Minute, and more importantly in this context of Mookie’s original question - How much air are they sucking in ? What kind of a windstorm might be encountered inside the locomotive hood near a running air compressor ?
The answer - after some research, because it’s hard to find even for a specific locomotive model - is probably a pretty good gale; you’d want to hang onto your hat, scarf, and any other loose clothing. Here’s the details:
A typical locomotive compressor rating might be in the 100 to 200 CFM range - and as large as 400 CF
I suspect you’d hardly notice it. 6 fps is about 4 mph - barely a brisk walk.
You don’t notice it. If you are standing in next to a GD WBO air compressor when it starts to load, you don’t notice the airflow at all.
Paul
You have thought this out very completely but. There is always a but. Out put is compressed air that has been contained and compacted into the storage vessel over time. We all know it takes a lot longer to fill that vessel than empty it. I work on trucks and heavy equipment and the 750 CFM compressors that are most common on these vehicles do not nearly suck as hard as they blow. Even our shop compressor that puts out 30 CFM @ 150 PSI only has a little piece of foam for an intake filter. I can actually hold my hand over the intake and take it away with little difficulty. To find out how much air it takes would take some math and knowledge of the compressor piston diameter and stroke. I can not remember the formula but it goes something like this. Bore diameter times bore diameter times stroke divided by Pi would give you the cubic inches than times 60 would give you the volume of air per stroke per minute times RPM.
Pete
The most common type of G-D compressor applied to current locomotives is the type WLN: 2 low pressure pistons @ 7 7/8" diameter and 1 hHigh pressure piston @ 5 3/4" diameter, all with a 5 inch stroke. This compressor is rated at 213 CFM @ 1050 RPM with a BHP of 65. GE engines run @ 1050 RPM in throttle 8, but EMD engines are 900 or 950 RPM so the maximum CFM and BHP for an EMD locomotive will be proportionally lower and of course if the engine speed is less than N8 output will be lower also. The standard intake filter is about 6" wide and 18" high. If you are right next to the intake when the engine is idle or low throttle notch, you can barely feel the air flow, but at the upper throttle notches it is noticeable.
The main reservoir pressue is set by the Chief Mechanical Officer of the railroad. FRA does not specify it. North American standard has been 135 psi for a very long time. The FRA does have requirements for the safety valve: “shall prevent the accumulation of pressure of more than 15 pounds per square inch above the maximum working pressure fixed by the chief mechanical officer of the carrier operating the locomotive” Rule 229.49(a)(1). This pu
N4 never its always N5 or N6 and motor driven dont need to be boosted, LOL yea right.
I think MoPac started the 120-130 psi main res setting.
I usually only go up to N4 to pump up. One time I ran some CN SD75Is. They automatically revved up to recharge after the train dumped. Fun watching the engine RPMs on the computer screen.
EMD locomotives 60 series and newer are equipped with a Main Reservoir Pressure Switch (MRPS) that speeds up the engine if the main reseroir pressure drops below 110 psi for 120-130 main reservoir pressure and 115 for 130 - 140 psi main reservoir pressure. The MRPS was applied per my specification to solve a problem that occurs when a long train with only 1 or 2 units is moving in medium levels dynamic brake and the low engine speed is not turning the shaft driven compressor fast enough to keep up with train air pressure maintaining and horn usage. “I blow the horn 3 times and my brakes set up” complaints. Tried to apply MRPS on Dash2 locomotives, but the engine speed-up caused the dynamic brake to be unstable. Dash2 excitation control cannot “turn down” the main generator excitation enough to get along with the increased generator rotation speed and there were long periods of no excitation which caused dynamic brake to “hunt”. Micro-processor excitation control has a wider range of control over excitation. GE’s with motor driven compressors doe not need MRPS, however if there is a motor control problem on a single leading unit that delays the start-up of the compressor, main reservoir pressure can get low enough to cause train brakes to set-up when the horn is blown and to release the train brakes when the compressor starts to pump - without the engineer touching the automatic brake handle.
tleary01/ DPman - Now *there’*s a couple of answers ! Thanks much for your time and effort in replying with that much detail. [tup]
Now, a couple of follow-up questions, if you’ll indulge mea little further:
The Conrail EC-99 brake book gives the following charging times:
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Times based on 50 ft. uncharged cars. Shorter times shown are for minimum brake pipe leakage, longer times are for maximum allowable brake pipe leakage.
Obviously that’s going to vary, but it might help you with your computations. Al Krug’s North American Freight Train Brakes may also provide some insight.