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Railroaders' Nostalgia > Charging your MR


Date: 01/16/24 19:43
Charging your MR
Author: ApproachCircuit

Didn't someone just mention going to run 4 to charge their MR?
I always understood from the powers to be that anything over 2 was just a waste of RPM's.
The charging oriface off the compressor was designed for idle to run 2.
But on the SP we had mid-train remotes with restricted charging (8350, I forget the other numbers) that were occasionally put on the head end and you sure had better be aware of the fact!!
But on the old 6's and 8's and some 24's, before modification you could blast that BP with MR! Now wasn't that fun!!



Date: 01/16/24 21:17
Re: Charging your MR
Author: SanJoaquinEngr

The SP Locotrol SD40T2 remotes were equipped with a smaller brake pipe orifice when cut into the train . The reason why was when the engineer made a set from the headend the helper engine would sense an application and set the brakes to the same setting of the application.
I was at Saugus one day headed westbound. Had the 8355 on the point. Had to cut the crossing because was awaiting an eastbound train. Coupled back to the train and couldn't get the air back up on the train. Apparently the orifice had been replaced but apparently not. Ended up switching out the units and the air came up on the train without any further issues.
Actually to answer your other question. Anything throttle position above run 1 was a waste of fuel and the train didnt charge up any quicker.
The earlier switcher units i.e. the SW 1 s up to the SW 1200 needed the extra throttle positions to pump up the air pressure.
One UP engineer worked a job with SD 70s he still thought that placing these engines in run 8 pumped the cars up faster. The RFE told him to knock it off after he observed his throttle positions on a download. As I remember the EMDs and the GEs had a metal plate stating that maximum throttle position was run 1 for train charging.

Posted from Android



Date: 01/17/24 06:27
Re: Charging your MR
Author: LocoPilot750

Makes no difference now, because compressors run off an electric motor, On modern power you have no control of what it does or doesnt do, it's no longer dependent on engine rpm. Santa Fe wanted us to pump air in no greater R-4, because anything above that could be harmful on an unloaded diesel engine. And later, they added to that by saying to increase rpm to just stay 10 psi above the brake pipe when charging a train.

Posted from Android



Date: 01/17/24 13:41
Re: Charging your MR
Author: Drknow

The other night the usual fiasco of when 2 snowflakes meet and the RR crashes happened, took 4 days to unstick a train. Engineer was pumping Air in notch 3 and was having a hard time with the flow. MIC on site sez go to notch 8, I got on radio and sez that won’t do any good; His retort? yes Iit will!

I just shook my head and said “oh, yes, you’re right.”

Don’t care anymore, and nothing I do will make a difference anyway. 🤷‍♂️

Posted from iPhone



Date: 01/17/24 16:09
Re: Charging your MR
Author: JasonCNW

Drknow Wrote:
-------------------------------------------------------
> The other night the usual fiasco of when 2
> snowflakes meet and the RR crashes happened, took
> 4 days to unstick a train. Engineer was pumping
> Air in notch 3 and was having a hard time with the
> flow. MIC on site sez go to notch 8, I got on
> radio and sez that won’t do any good; His
> retort? yes Iit will!
>
> I just shook my head and said “oh, yes,
> you’re right.”
>
> Don’t care anymore, and nothing I do will make
> a difference anyway. 🤷‍♂️
>
> Posted from iPhone

Where I work, one night the kid who was operating the engine was pumping air into some cars we tied into.

As I was walking back to the engine I could hear it in high idle. As I walked into the cab I asked him what notch he was in he said "8" I quickly told him throttle it down now,Ive told you before no higher then notch 4. Just as I said that BOOM! We blew up the air compressor, there was oil and bits of metal all over the air compartment of our GP15,,that was a mistake he never made again.
JC

Posted from Android



Date: 01/17/24 17:19
Re: Charging your MR
Author: Englewood

In a multiple unit consist do all the units pump air or just the leader ?



Date: 01/17/24 17:23
Re: Charging your MR
Author: HotWater

Englewood Wrote:
-------------------------------------------------------
> In a multiple unit consist do all the units pump
> air or just the leader ?

Yes, all the air compressors pump, as all the main reservoirs are train-lined through the MR Line.



Date: 01/18/24 14:40
Re: Charging your MR
Author: Englewood

HotWater Wrote:
-------------------------------------------------------
> Englewood Wrote:
> --------------------------------------------------
> -----
> > In a multiple unit consist do all the units
> pump
> > air or just the leader ?
>
> Yes, all the air compressors pump, as all the main
> reservoirs are train-lined through the MR Line.

Thank you for the answer.  When I was at amtrak I got as many different answers to that
question as RFE's I asked.



Date: 01/18/24 14:49
Re: Charging your MR
Author: engineerinvirginia

When compressors are engine operated through a drive shaft for example...run 4 is the max....as said it's just not good for an unloaded engine, but also, any additional compressor speed won't give you more air, because the flow through the charging orifice will only allow so much through...once that maximum is reached you are just making the air compressor hot for nothing. 



Date: 01/18/24 19:36
Re: Charging your MR
Author: Trainhand

Back to the original problem, it only ahppened with the SD 60's that came from Conrail. I would be on the empty juice train from Florence, and at Lake City, SC there is a road crossing for every street for about a mile and half. Its a slight downgrade going south, and I would be stealing all the speed I could, usually to stay ahead of the Auto Train, so I couldn't let the air on the train pull me down. I've had more than one RFE tell me this could not and would not happen. It would every night you would have 40-50 juice cars and one SD 60. 
It was one of those things that the mechanical instructer I had in engineer's school refered to, if an engine starts making ice cream get your dish and spoon and eat it.

Sam



Date: 01/18/24 23:19
Re: Charging your MR
Author: Brasspounder

HotWater Wrote:
-------------------------------------------------------
> Englewood Wrote:
> --------------------------------------------------
> -----
> > In a multiple unit consist do all the units
> pump
> > air or just the leader ?
>
> Yes, all the air compressors pump, as all the main
> reservoirs are train-lined through the MR Line

Also, in an MU consist, the air compressor governors are also tied together, all of the compressors start and stop in unison. Pin 22 of the 27 pin mu plug.

Posted from Android



Date: 01/19/24 07:11
Re: Charging your MR
Author: engineerinvirginia

Obvilously if you have several engines the whole train will pump faster, but the max that each engine can contribute is limited by it's own charging orifice. Better to have more than one on line. And I woulnd't want to have worked on the Seaboard or ACL....one engine wonders all over the place after CSX came to be. 



Date: 01/19/24 07:41
Re: Charging your MR
Author: LocoPilot750

I've been on several air dump work trains, and they gobble up a lot air in a hurry when dumping. Usually had about 8 cars, and they want to dump them all right there in a row two at a time. I remember one where we had two GP20's and they barely kept up. I had both MR lines connected for faster flow between the units, and they were dumping with MR air. Those units both had water cooled six cylinder compressors, but still were struggling to dump two cars at a time. I tried to stay in R-4 to keep up, but found that R-8 did a little better, but still lagged. At the time, I think those 3100's were the only ones with 6 cylinder compressors, and I don't know if they put them on the work train because of the higher capacity, or if it was just a fluke. The normal three cylinder compressor is 200 cfm, the 6 cylinder version was 375 cfm.



Date: 01/19/24 08:24
Re: Charging your MR
Author: ts1457

LocoPilot750 Wrote:
-------------------------------------------------------
> I've been on several air dump work trains, and
> they gobble up a lot air in a hurry when dumping.
> Usually had about 8 cars, and they want to dump
> them all right there in a row two at a time. I
> remember one where we had two GP20's and they
> barely kept up. I had both MR lines connected for
> faster flow between the units, and they were
> dumping with MR air. Those units both had water
> cooled six cylinder compressors, but still were
> struggling to dump two cars at a time. I tried to
> stay in R-4 to keep up, but found that R-8 did a
> little better, but still lagged. At the time, I
> think those 3100's were the only ones with 6
> cylinder compressors, and I don't know if they put
> them on the work train because of the higher
> capacity, or if it was just a fluke. The normal
> three cylinder compressor is 200 cfm, the 6
> cylinder version was 375 cfm.

That's interesting. When I distributed power for a few years in the early 1990s, my favorite place to put a GP20 was on a work train.

I had no knowledge of the compressor configuration when I was doing that. I had other reasons.



Edited 1 time(s). Last edit at 01/19/24 12:03 by ts1457.



Date: 01/19/24 12:12
Re: Charging your MR
Author: SanJoaquinEngr

The dreaded air dump cars. I worked with an ex carmen that switched to train service. We had to take several air Dumps on the Saugus line between Lang and Russ to fortify the river bank. The cars were loaded with rip rap , old tires, dirt and ballast. Had 2 GP 9$. He was smart and found a dummy hose that had the MR gladhands on both ends. That way we could move the train and still charge up the dump cars. Worked like a charm . i kept the hose for many years..

Posted from Android



Date: 01/21/24 10:27
Re: Charging your MR
Author: wcamp1472

What are the choices for charging the dump-tanks on the rock cars?
What is the conventional source of air for the the dump tanks?
Before diesels, what did they do?
How do use the hose with 2 MR couplings ?

W.
 



Date: 01/22/24 07:37
Re: Charging your MR
Author: flash34

Wes, in my experience you would hook the brake pipe hose at the rear up to the dump hose. That was the only option without a MR connection.



Date: 01/22/24 08:46
Re: Charging your MR
Author: Railbaron

wcamp1472 Wrote:
-------------------------------------------------------
> What are the choices for charging the dump-tanks
> on the rock cars?

When they were rebuilding the mountain after the Frazier Slide on the SP in Oregon we used a lot of air dump/side dump cars to move lots of dirt and debris. Because charging was an issue they added a flat car with a large compressor in the middle of some trains so that compressor would charge the dump system all the time and the cars would dump faster without relying on the locomotives.



Edited 1 time(s). Last edit at 01/22/24 08:46 by Railbaron.



Date: 01/23/24 08:34
Re: Charging your MR
Author: NSDTK

Not any more. That was only on a few railroads back in the day, Now non one uses compressor synchronization
Brasspounder Wrote:
-------------------------------------------------------
> HotWater Wrote:
> --------------------------------------------------
> -----
> > Englewood Wrote:
> >
> --------------------------------------------------
>
> > -----
> > > In a multiple unit consist do all the units
> > pump
> > > air or just the leader ?
> >
> > Yes, all the air compressors pump, as all the
> main
> > reservoirs are train-lined through the MR Line
>
> Also, in an MU consist, the air compressor
> governors are also tied together, all of the
> compressors start and stop in unison. Pin 22 of
> the 27 pin mu plug.
>
> Posted from Android



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