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Rutgers Tube

Air compressors

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With trucks and other motor vehicles equipped with air brakes, increasing the throttle will increase the rate that compressor replenishes the air in the reservoirs. Do train cars work with the same concept?

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As far as I know, the compressor will com on when the air pressure in the reservoir drops below a certain point. If there is a small leak, it will cycle on more then if there are no leaks. If there is a sudden drop in pressure, the breaks will go BIE (breaks in emergency). I'm sure if Subwayguy sees this he can go more in depth then I can.

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I don't think trains work this way, as there isn't a safe way I know of to increase the throttle to get more air in the tanks. I know what you are talking about with trucks and buses, as when I was a B/O, we use to keep the bus in neutral, the parking brakes on, and gun the gas pedal, to build up air pressure faster. With electric trains, I don't think we can do this. Diesel maybe. Some senior T/O's on here should be able to answer this question(s).........

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You know, the one aspect of trains which I always have difficulty understanding is the air brake system, and that's probably because I've been driving trucks for a while now and those air brake systems function somewhat differently. When a train is stopped at the station, I can hear the compressors kick in, most prominently (to me, anyway) on R44 and R46 equipment. I always seem to get this confused, but I believe the train charges the air pressure while the brake is held in the "Release" position. Here is where a T/O can help me figure this out: are T/O's instructed to wait until the train is fully charged before moving a train, or can a train be moved and the compressor automatically cuts out once the air pressure reaches the governed level, and if so, does an increase in throttle increase the compressor charge rate?

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When a train is stopped at the station, I can hear the compressors kick in, most prominently (to me, anyway) on R44 and R46 equipment. I always seem to get this confused, but I believe the train charges the air pressure while the brake is held in the "Release" position. Here is where a T/O can help me figure this out: are T/O's instructed to wait until the train is fully charged before moving a train, or can a train be moved and the compressor automatically cuts out once the air pressure reaches the governed level, and if so, does an increase in throttle increase the compressor charge rate?

 

Compressors tend to kick in after a station stop because the stored air in the reservoirs was used in order to stop the train. Generally, the compressors will kick in when the brakes are placed in full service, or maximum air brake (80 lbs. on SMEE/46's, 110 lbs. on 44's) , because the amount of air pressure that is requested cannot be attained by what is currently available in the tank. If the T/O is holding only a 15-20 lb. brake, the reservoir air should be more than sufficient to maintain the pressure requested.

 

And yes, before moving we must wait until the air brakes have been fully charged or the train won't move an inch. Lastly, subway trains don't have throttles like trucks do since the trains are electrically powered.

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Compressors tend to kick in after a station stop because the stored air in the reservoirs was used in order to stop the train. Generally, the compressors will kick in when the brakes are placed in full service, or maximum air brake (80 lbs. on SMEE/46's, 110 lbs. on 44's) , because the amount of air pressure that is requested cannot be attained by what is currently available in the tank. If the T/O is holding only a 15-20 lb. brake, the reservoir air should be more than sufficient to maintain the pressure requested.

 

And yes, before moving we must wait until the air brakes have been fully charged or the train won't move an inch. Lastly, subway trains don't have throttles like trucks do since the trains are electrically powered.

 

Thanks, Z. That last sentence made me actually look at the definition of a throttle, since I always associated it with a master controller. Rather, a throttle is just a mechanism controlling air and fuel intake, which the revenue trains obviously do not have!

 

Is there a particular model car that seems to brake much more aggressively or smoother than the others, or one that you favor?

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No trains don't work that way. A governor detects main reservoir air, and this controls the compressor. When it drops below a certain point, the compressor starts and the air begins pumping increasing the pressure. A SMEE car has two pipes - straight air pipe, and brake pipe. The brake pipe is charged with a certain amount of pressure (110 lbs) and it is supposed to hold this. Any sudden decrease, and the brakes apply in emergency. The straight air pipe just acts as the "intermediary" if you will between the Main res and the brake cylinder. So when a T/O applies service friction brake, air goes into the straight air pipe, and then flows into the cylinder and applies the brake.

 

It's more complicated than that because you also have dynamic brakes, slack adjusters, and variable load valves doing their part (that's another thread...seriously), but the short answer is when the air pressure dips below a certain point, the compressor automatically is started by the governor and begins restoring air pressure, and like Zman said most often this is after a large application has been made (like bringing the train to a stop) because it takes air out of the main res, into the SAP, and into the cylinder to stop the train. This leaves less air in the main res, and if it's less than the "minimum" the governor senses, so the compressor kicks in and starts pumping more air.

 

On older cars (AMUE type equipment like R9's) the brake is recharged in release or electric hold. On SMEE cars, there is a separate charge "notch" if you will in the brake stand which charges the brake pipe.

Edited by SubwayGuy

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Is there a particular model car that seems to brake much more aggressively or smoother than the others, or one that you favor?

 

Every train is different. Some brake to hard, and some smooth. Crazy part is it can just depend on the end you operate from. No two trains brake the same, no two ends on the same train will brake the same when operating from the other end.........

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No trains don't work that way. A governor detects main reservoir air, and this controls the compressor. When it drops below a certain point, the compressor starts and the air begins pumping increasing the pressure. A SMEE car has two pipes - straight air pipe, and brake pipe. The brake pipe is charged with a certain amount of pressure (110 lbs) and it is supposed to hold this. Any sudden decrease, and the brakes apply in emergency. The straight air pipe just acts as the "intermediary" if you will between the Main res and the brake cylinder. So when a T/O applies service friction brake, air goes into the straight air pipe, and then flows into the cylinder and applies the brake.

 

It's more complicated than that because you also have dynamic brakes, slack adjusters, and variable load valves doing their part (that's another thread...seriously), but the short answer is when the air pressure dips below a certain point, the compressor automatically is started by the governor and begins restoring air pressure, and like Zman said most often this is after a large application has been made (like bringing the train to a stop) because it takes air out of the main res, into the SAP, and into the cylinder to stop the train. This leaves less air in the main res, and if it's less than the "minimum" the governor senses, so the compressor kicks in and starts pumping more air.

 

On older cars (AMUE type equipment like R9's) the brake is recharged in release or electric hold. On SMEE cars, there is a separate charge "notch" if you will in the brake stand which charges the brake pipe.

 

Speaking of the older cars, like the R9's, didn't they take more skill to brake as you had to manually lap them?

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Speaking of the older cars, like the R9's, didn't they take more skill to brake as you had to manually lap them?

 

Yes. Without going into too much more detail and "how to operate a train" you had to manually lap them which resulted in you moving the brake handle a lot more than on a SMEE car.

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Speaking of the older cars, like the R9's, didn't they take more skill to brake as you had to manually lap them?

 

That seems to be the question of the day.

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That seems to be the question of the day.

 

Heh...got that right..."third time's the charm" - however not giving the detail speech you guys got. Next time you come up, you can try your hand on the Lo-V.

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Heh...got that right..."third time's the charm" - however not giving the detail speech you guys got. Next time you come up, you can try your hand on the Lo-V.

 

I asked Jeff about doing the Brooklyn Elevated but he said it needs a paint of coat, so I guess I'll probably try my hand on the Low-V though I would like to do the Brooklyn Elevated since you reminded me about it. BTW, where did you guys go? We were looking for you and Matt but we couldn't find you guys.

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I asked Jeff about doing the Brooklyn Elevated but he said it needs a paint of coat, so I guess I'll probably try my hand on the Low-V though I would like to do the Brooklyn Elevated since you reminded me about it. BTW, where did you guys go? We were looking for you and Matt but we couldn't find you guys.

 

I tried calling you, your phone didn't even ring, went straight to Voice Mail...what do you have T-Mobile? ;) B)

 

We were out back in the yd putting the R-17 away, only one of the more rickety pieces of equipment was in our way and none of us was qualified or willing to move it so we were "stop and stay"

 

And that's OK...you will want to learn (at least the basics of) AMUE and the Lo-V before you ever attempt an el car and AML :eek:

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I tried calling you, your phone didn't even ring, went straight to Voice Mail...what do you have T-Mobile? ;) B)

 

We were out back in the yd putting the R-17 away, only one of the more rickety pieces of equipment was in our way and none of us was qualified or willing to move it so we were "stop and stay"

 

And that's OK...you will want to learn (at least the basics of) AMUE and the Lo-V before you ever attempt an el car and AML :eek:

haha no got Sprint but I forgot to charge my phone overnight so my cellphone was dead by the end of the day. We ate at the diner, came back and Jeff said he didn't know where you guys were, so we went home since he said there wasn't much shop work out.

 

PS "a paint of coat?" It's not the wintertime yet... :P

Hey, it's 1:30 in the morning :P I'm tired. You know what I meant :P

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haha no got Sprint but I forgot to charge my phone overnight so my cellphone was dead by the end of the day. We ate at the diner, came back and Jeff said he didn't know where you guys were, so we went home since he said there wasn't much shop work out.

 

Yeah Jeff had just gotten back himself after dropping James off and he met up with another worker who he saved some electrical equipment for after that so he hadn't been around for the last run to short beach and the yard move to put the car to bed because he was at the New Haven train station. Then once he got back you guys were going to get dropped off. Next time let us know if everyone wants to stay and we can come up with a project to tackle, but I had only assumed you were staying, didn't know about those other guys.

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Yeah Jeff had just gotten back himself after dropping James off and he met up with another worker who he saved some electrical equipment for after that so he hadn't been around for the last run to short beach and the yard move to put the car to bed because he was at the New Haven train station. Then once he got back you guys were going to get dropped off. Next time let us know if everyone wants to stay and we can come up with a project to tackle, but I had only assumed you were staying, didn't know about those other guys.

 

Yeah I wanted to get my hands dirty but I didn't want to let these guys get lost. Count me down next time for anything. I guess Jeff didn't know how many people were going so he didn't have anything ready. Well till next month I guess.

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Yeah I wanted to get my hands dirty but I didn't want to let these guys get lost. Count me down next time for anything. I guess Jeff didn't know how many people were going so he didn't have anything ready. Well till next month I guess.

 

Yeah...part of that is it's been a little bit of a lull. A lot of stuff was moved up from NY lately and sitting in a trailer but we haven't cleared space for it just yet and Jeff has stuff going on at work in the meantime. There were some minor projects me and Matt want to do on the R17 but they will hardly take 3+ people. Coming up there will be plenty of things they just require a little bit more planning. Plus I wasn't sure if any of those guys were going to bring cameras and want to get photo's of equipment in the yards etc. like most do their first time up. It's no big deal, there wasn't a lot done, but next time I will count you in and if those guys choose to stick around we can set that up as well, plus you won't miss Chili's at the end ;).

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Yeah...part of that is it's been a little bit of a lull. A lot of stuff was moved up from NY lately and sitting in a trailer but we haven't cleared space for it just yet and Jeff has stuff going on at work in the meantime. There were some minor projects me and Matt want to do on the R17 but they will hardly take 3+ people. Coming up there will be plenty of things they just require a little bit more planning. Plus I wasn't sure if any of those guys were going to bring cameras and want to get photo's of equipment in the yards etc. like most do their first time up. It's no big deal, there wasn't a lot done, but next time I will count you in and if those guys choose to stick around we can set that up as well, plus you won't miss Chili's at the end ;).
Is that waitress back at chilli's? or still out on vacation? I liked her, she took care of us and hooked us up with those drinks. :cool:

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Is that waitress back at chilli's? or still out on vacation? I liked her, she took care of us and hooked us up with those drinks. :cool:

 

Heh...she's still there. Hooks me up with my Dr. Pepper's :cool:

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Yeah I wanted to get my hands dirty but I didn't want to let these guys get lost. Count me down next time for anything. I guess Jeff didn't know how many people were going so he didn't have anything ready. Well till next month I guess.

 

Yeah! I was looking forward to some shop work.

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Thanks, Z. That last sentence made me actually look at the definition of a throttle, since I always associated it with a master controller. Rather, a throttle is just a mechanism controlling air and fuel intake, which the revenue trains obviously do not have!
Our diesel equipment does have them, however. (I've never messed with that stuff, though).

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Our diesel equipment does have them, however. (I've never messed with that stuff, though).

 

Thanks, Eric. Are those work trains dual-powered with third rail shoes, or just straight diesels? I see them run the diesels on live rails, but that doesn't necessarily mean that they lack shoes.

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Thanks, Eric. Are those work trains dual-powered with third rail shoes, or just straight diesels? I see them run the diesels on live rails, but that doesn't necessarily mean that they lack shoes.

 

There are a few duel modes but I think most are diesel. Actually now that I think of it, almost all the dual modes I have seen have had there 3rd rail shoes cut off.

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