Northtowne Very good answers, thanks to all. Since I am OCD, I probably would never the air hoses and MU connections right. Northtowne
Very good answers, thanks to all. Since I am OCD, I probably would never the air hoses and MU connections right.
Northtowne
While nothing is idiot proof - connecting the proper hoses is as simple an operation as is possible. You have your normal trainline brake hose that is immediately adjacent to the coupler & draft gear and can only be coupled to a like kind of hose on the engine or car it is coupled to.
Along the pilot, and on each side are the 4 pneumatic actuating hoses that are coupled to the like hoses on next engine. Only one set of the 4 hoses must be coupled for proper operation of the engine consist. The coupling of these hoses are direct - inside hose to inside hose; next inside to next inside etc. until all 4 hoses have been coupled. Behind each hose is a valve to permit the actuating pressure to be moved through the hose or to be cut off. After coupling the hoses each of these valves on each engine should be positioned to permit the actuating pressure to be active through the hoses. All the hoses are fitted with glad hands and when the locomotives are uncoupled from each other, the hoses will uncouple automatically just like the trainline air hose. Before uncoupling the valves controlling each hose should be closed on each engine.
Never too old to have a happy childhood!
Thanks, fluff and Don.
Johnny
I think I can answer both of these questions.
Locomotives have a "isolation switch" which disconnects the traction motors from the main generator (among other things) by means of some big switches called contactors. Since the motors aren't connected to anything, turning the armature against any residual magnetic field in the windings results in no power generation since you have an open circuit.
Brakes on locomotives are MUed via the air hose between units. One of the air hoses connects all the main reserviors together, another controls the application of the independent brake. If the engineer applies the independent brake from the lead locomotive, it applies on all the trailing locomotives, regardless if they are "on line" or not.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
the engines wil remain laced up whether running or not. if you shut an engine down, its compressor is not pumping air. yesterday, with 2 sd 45's, one was low on fuel so i shut it down and just towed it home with the lead. light engine move. sometimes when its cold, and dont need the power, we isolate them and they just idle. if you want it quiet going home lite, or with a short train, isolate the lead emgine and let the others do the work. you can also shut down the lead and still operate the train with it.
Mac, this raises a question in my mind: as I understand engine brakes, they work on straight air; are the air compressors on the dead engines working to provide air for their brakes, or is there a connection to the train line going to the cars behind that provides the straight air?
I think of the student fireman on a steam engine when told, "That pipe is for straight air," wondered, "How do you put straight air into such a crooked pipe?"
Northtowne,
A light engine move refers to taking an engine from here to there without a train. The units are usually fully operable, they just are not pulling a train.
The tone of your question seems to be dead in tow, when the unit is not providing any tractive effort to move itself or a train. Dead here means that the prime mover is shut down. As a practical matter the generator field switch will be OFF as part of the shut down proceedure. If a unit is DIT, then yes the control stand is cut out and the unit's brakes respond as if it were a car.
Mac
I don't understand even the basics of electricity. When you move a loco light I assume the traction motor insides and the gear to the axle turns. Is this the only movement of the rest of the power components? Does this create any backward current, etc? Are the cables from the generator to the trac mtrs switched off as well as other cab control items? Does the air from the motive power units pass thru the light units and operate the brakes as if it were typ rolling stock? (If so, this must involve complicated piping and valving).
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