How do you “wizz the air away”?[?]
This is a good topic, keep it up.[8D]
Adrianspeeder
several set and releases will wizz ( polite way of saying ****) your air away. everytime you set your brakes you take air from the system to do this. the air has to be replaced. this takes time with a mile long train. you have to recharge the main resevoir on every car. ( this is for maximum braking) . to make the quick release work you haft to take a minimum of 10lbs of air from the system. to release it only takes 3lbs of air. but. the system is not 100% recharged just because you release the brakes . so let me give you a senerio.
1 i am comming down a hill 9500 tons of train 6200 ft long. dynamic wont hold me at the speed that is needed so i must get air. i grab 10 lbs so now i am comming down hill with air brakes applied and controlling speed with air and dynamic. running 20 mph and slowing i am going to get to slow so i need to release the air . ( remember dynamic isnt good enough to hold me at speed) now the brakes are releasing and speed is creeping up. so to try and hold the train around 30mph i get 15 lbs now. ( Here is what hasnt been told. since i release the brakes the brake pipe is usually 90 lbs, i took 10 the first time that left 80 lbs avalible . when i released the system charges from front to back. so the first 15-20 cars might be charged to 90 but the rear isnt. so to get brakes on the rear i need to go past the 80 to a number below that like 75. the brakes only released due to a 3 lb rise in brake pipe not a charge in the system.) so i set the equilizer to 75lbs and the brake pipe follows . Now what i have done here is 2 things let my speed stay where the dynamic is at its optimal 24mph and set the brakes on the head end to hold the train with the rear only dragging. i have brakes on the hole train but not at the same application. everytime you set the air when you release and set it again you haft to go past your last setting to reapply the brakes 5 sets of the train brakes at a 10 lb set is 50 lbs minus that from 90 is 40 left. remeber you cant get a emergency application
scary stories, Wabash. And people think that engineers are paid to watch the scenery go by and blow horns to annoy the townspeople…
I must say that after thinking about it that 7 min per car was wrong it is 7 min per ( and this is the hard part to remeber) so many feet of train. to totaly charge a 6500ft train would be something close to 8-9 min. and in colder weather it is longer.
Wabash,
We were taught it was 7 to 8 minutes for every 100 cars,(5000 feet) longer in cold weather.
Still havent found the mirror!
Stay Frosty, and Merry Christmas,
Ed
Ed and J, Book I have says 8 min plus 30 seconds for each additional
car (for 2 cars eight and a half min, 3 cars would be nine min) it also
says if the system is completly devoid of air, probably means if it were
bled off
Ed and Jack
This is the problem. The way i see it we have 3 railroaders here and we have the time right but that is where we differ is the amount of cars. i dont have the paper work here to refer to. jack if i read it correctly your saying per car. and ed and i are saying per 100 cars on a 50ft car size. I was given that info many years ago but i have left it lay somewhere and dont use it for referance. but the way it seems is that each carrier has a differant time limit on when a car is properly charged. I remeber that they said this is after you cut away ( same as a emergency applacation) and come back to recharge the system. and it was slightly less on just a normal application of the brakes ( 2-3 min) this makes it hard to give right information when carriers do it differant, needs to be more uniform. also you guys know as well as i do that when the rear reads 75 ( 60 in eds yard work) we move the train. if your in the hills you want it air up more if your flat land 75 is fine.
I would believe that csx engineer would agree with me here. when you move depends on what is ahead to do. if i have a train 9400 tons and using 3 SD40s and i make a pick up and 1 mile up the road i haft to take the hole to meet a train,( that isnt there yet and its a slight down grade) i need to stop and get the switch and head in. instead of 75lbs on the rear i might want them at 85 or even fully charged. ( sd 40s dont have extended range dynamic brakes) so i can use the air to stop. Now again lets say i made a pick up and only have 3000 tons and 2 dash 9 i will move with 75 on the rear and stop with dynamic maybe a slight bit of air cause the engines i am using do most of the work so i dont haft to depend on the air . ( before i forget for those that dont know why 75lbs on the rear you are not supposed to move til your brake pipe is with in 15 lbs of feed valve setting or what the air pressure is supposed to be. 90lbs is standard 75 is with in the 15lbs feed valve setting) .
tha
Rank has it’s privildges…
I get the radio switches, he gets the rest.
Stay Frosty,
Ed
J I think we are saying about the same thing, we know that after an
emergency application, after we re-set it’ll take 8 to 10 minutes and ole
FRED is showing about 75 psi. what I was saying about the 8 min.
plus 30 seconds for each other car was when the cars are completely void
of air. It says here…57 minutes to fully charge 100 cars that were
completely void of air (key word here is completely void) Also remember just because the brake pipe is
showing 75 psi the car reserviors probably dont have near that much in
them yet because of the choked charging ports, I fully agree with your description of stopping using DB with the big ACs or DASH 9s, really
takes a lot of the guess work out of it, makes it easy for everybody.
do more locos help pump up air faster? do helpers on the rear get involved with the air brakes?
thanks
Adrianspeeder
Back to the days of steam when the train pipe pressure for freight was 90psi and for passenger 110psi.
I was looking at the Santa Fe operation on Raton Pass where the train engine was a 4-8-4 passenger loco and the helper was a 2-10-2 freight loco.
As I understand operating procedures the engineer of the lead loco (the 2-10-2) would control the train brakes, but his normal system would be 90psi full release and 64psi full service application.
The train loco would be 110psi full release and 79psi full service application
So, from this it seems that the train loco and the cars would only get to 90psi in released position and this would be equivilant to about a 70% brake application.
Obviously this is not workable up grade so the question is what method was used to get full release when the helper was controlling the brakes?
Ian
yes and no… more engins will make more air faster…but you can only pump so much through the trainline at one time…
csx engineer
10lbs of air! Well, there was your first mistake. Try keeping your speed down below the limit and use “First Service” first. Give it time to set up and see what happens. I can stop a 15,000 ton coal train with pushers on the side of a mountain with 10lbs of air.
Something else to keep in mind, if you get over the speed limit and have to use more air to slow down, then you have used too much air and will have to knock it off before you stall and that is when you get into the pissing contest!
The lead engine should have upped his pressure to 110lbs with the feed valve for use in passenger service and there would not have been any problem. Even at that, I doubt there was any problem to begin with as long as the trainline hadn’t been overcharged by the passenger engine to begin with. If it had, it would only be a matter of making several big reductions in order to get rid of the overcharge in the brake system.
and no…the helper units have there automatic brakes cut out… if they where cut in anytime the head end made a brake application…the helper engins brakes would be trying to pump it off so nothing would happen…
csx engineer
…and I thought he would tell us the 5 functions of an A-1 charging, cut-off pilot valve or maybe the MU-2A on the 24RL system…[:o)]
Hey Rick,
Nice to see…uh, read you again…been keping ok?
Jim,
Thanks for the prompt reply, I was not aware that the freight locos had this capability, but it makes sense that they would.
Ian