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DP- why so late to the game?

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DP- why so late to the game?
Posted by Murphy Siding on Sunday, December 19, 2021 7:16 PM

In relative terms, it seems like it took a long time for distributed power to become a common thing. Why? Was it technology or communication that was holding it back?

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Posted by BaltACD on Sunday, December 19, 2021 7:52 PM

Murphy Siding
In relative terms, it seems like it took a long time for distributed power to become a common thing. Why? Was it technology or communication that was holding it back?

For CSX - at least in my territory it was a communications thing.  A number of 'repeater stations' had to be installed at various locations on the territory whereradio communications was being lost between the leader and trailing DP units.

I heard a 'story' from one of the Western roads that were among the early users of DP if a occurence where the lead section of the train that had broken in tow was about 10 miles ahed of the 'rest of the train' - and both were proceeding at track speed. I have no idea if that is a truthful story or not.  

There are a number of locations where there is no cell phone service.

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Posted by tree68 on Sunday, December 19, 2021 7:52 PM

I suspect it was a number of factors.  Recall that at least one railroad used a car to carry the equipment in the early days.

The technology is a huge player in this.  Radios have grown smaller and smaller - I can carry a 100 watt radio in the palm of my hand - a radio that used to take several large chassis.  

So, too, the technology of the signal.  I can't claim to know what they are using, but I'm sure there is error checking involved, probably a product of network technology.

Cost would be a factor - you'd really need to have a substantial amount of your fleet equipped in order to be able to use DP on a regular basis.  It wouldn't do to have several locos available, but have them lack DP capability.

And, I suspect that good old "we've always done it this way" counts for something as well.

We must also consider training...

That virtually everyone is using DP speaks to the probability that they are seeing benefits, and such benefits certainly speed the process along.

That said, I watch Deshler a lot, of course, and it's gotten to be rare to see a train come through sans DP.  I also see that when visiting Utica to work on the Adirondack.

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Posted by BaltACD on Sunday, December 19, 2021 8:12 PM

tree68
I suspect it was a number of factors.  Recall that at least one railroad used a car to carry the equipment in the early days.

The technology is a huge player in this.  Radios have grown smaller and smaller - I can carry a 100 watt radio in the palm of my hand - a radio that used to take several large chassis.  

So, too, the technology of the signal.  I can't claim to know what they are using, but I'm sure there is error checking involved, probably a product of network technology.

Cost would be a factor - you'd really need to have a substantial amount of your fleet equipped in order to be able to use DP on a regular basis.  It wouldn't do to have several locos available, but have them lack DP capability.

And, I suspect that good old "we've always done it this way" counts for something as well.

We must also consider training...

That virtually everyone is using DP speaks to the probability that they are seeing benefits, and such benefits certainly speed the process along.

That said, I watch Deshler a lot, of course, and it's gotten to be rare to see a train come through sans DP.  I also see that when visiting Utica to work on the Adirondack.

I retired in 2016.  Begining in about 2010, all the new engines CSX were buying were being equipped with DP equipment.  On my territory, CSX did not start using DP until sometime after I retired.  They were using DP on some more communications friendly territories before I retired.

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Posted by jeffhergert on Sunday, December 19, 2021 8:25 PM

BaltACD

 

 
I heard a 'story' from one of the Western roads that were among the early users of DP if a occurence where the lead section of the train that had broken in tow was about 10 miles ahed of the 'rest of the train' - and both were proceeding at track speed. I have no idea if that is a truthful story or not.  

 

I know it happened out in western Nebraska (IIRC) in the mid 1990s.  It had to be deliberate because for this to happen anglecocks on both portions need to be closed.

There are tests/procedures that are to be done to ensure things like this don't happen.  Even so, it would still be possible to separate a train if you knew what to do and when to do it.

Jeff  

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Posted by blue streak 1 on Sunday, December 19, 2021 9:41 PM

SOU RR was probably one of the first.  They had a set of converted box cars called radio cars.  They had a few locos with the control equipment insttalled.  You could identify the control cars because they were installed with white number boards and had some kid of letering on the sides?  The set up was used omainly on coal trains from SW virginia - Ashville -and down Saluda.  Saluda trains had a road foreman who joined the train at top of hill and got off somewhere at the bottom.  The DP unit would push train up hill as front had already gone into dynamic,  Then both on dnamic downhill at less that 10 MPH.

Someone may have link to SOU's video instruction.

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Posted by Gramp on Sunday, December 19, 2021 11:18 PM

I saw a CN doublestack yesterday with DP midtrain that had what looked like a specialized boxcar on the end. It was painted CN orange with no tagging and had a passenger car-like door on the side as well as the normal sliding door. Would that be used for DP related equipment?

I saw another double stack about a month ago with a white boxcar immediately behind the engines with the word "INSPECTION" in large stenciled letters painted vertically on the boxcar side. 

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Posted by SD70Dude on Sunday, December 19, 2021 11:22 PM

The red boxcar you saw is officially called as a Distributed Braking Car, but is most commonly called an AirCar out on the property.  They contain a diesel genset and air compressor and perform all the air brake functions of a DP remote locomotive.  They also link to the lead unit using the same DP radio system.

The white/yellow boxcar is a track geometry car.  It tests the track and has nothing to do with DP or train handling.

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Posted by Gramp on Sunday, December 19, 2021 11:44 PM

Thanks, SD70dude

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Posted by JayBee on Monday, December 20, 2021 1:22 AM

Northern Pacific and Canadian Pacific were other early users of what became Distributed Power. In the early developement it was called "Locotrol" and was developed by Radiation Inc. They worked on radar equipment for the US Navy and were looking for some civilian markets for their radio technology. Locotrol progressed from version I which required a lot space which is why early users fitted the receiving equipment in boxcars or former B units. Through versions II which would fit in the cab of a locomotive but left no room for a crew when it wasn't being used as such, to version III which resulted in the EMD SD40-2s having "Snoot" noses. Version IV was developed just before Radiation, Inc. was bought by Harris Controls, which changed the marketing name to "Distributed Power". Eventually Harris Controls was bought by GE.

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Posted by daveklepper on Monday, December 20, 2021 6:06 AM

Thanks for the history.

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Posted by Ulrich on Monday, December 20, 2021 10:10 AM

CP has been using DP in Western Canada since the late 70s, perhaps earlier. When I lived in Kamloops, BC in the early 80s DP was pretty much commonplace on coal and grain trains. Likely advances in technology over the years along with the lengthening of sidings to accommodate longer trains made DP more practical in other areas. 

 

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Posted by cx500 on Monday, December 20, 2021 10:55 AM

CP was already routinely using DP in the unit coal trains between the Crowsnest and Vancouver by the summer of 1970.  The initial testing was done in the late 1960s.  CP continued to use the DP technology as Locotrol evolved, and subsequently expanded its use to all bulk trains through the western mountains, and then system wide.  They were willing to put the effort and resources through the early teething stages because the benefits were seen to be well worth the cost.  

Consider that CP started using DP less than 10 years after their last steam engine dropped its fire in 1960.  It has now been in continuous use for over 50 years.

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Posted by Euclid on Monday, December 20, 2021 11:24 AM
Rather than being late, I think DP just fell in step with a natural progression.  Dieselization introduced a big change by offering MU operation instead of a crew on every locomotive in the train, as was the case with steam.  DP was introduced in the 1960s, but I suspect it was under consideration much earlier, probably at or before dieselization began to take off.   I vaguely recall reading about a form of DP that used strain gage devices for unmanned helper diesel locomotives. 
 
I never learned how that worked, but I assume it was intended to tell the helper how much force to apply to the train.  I believe it was explained that the strain gages were measuring tensile force in the locomotive couplers and draft gear.  That seemed to be the general idea, although I am not sure how that was actually set up and used.  I don’t think it became popular.  The main challenge then was how to communicate with the remote units without MU wires.   
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Posted by timz on Monday, December 20, 2021 11:37 AM

Radio-controlled helpers with no engineer have been around since the 1960s anyway, but they were never widespread. In the 1970s the necessary equipment was on the engine -- no need for a separate radio car. But slaves still didn't spread -- SP tried them but didn't bite; UP tried them but didn't bite.

Now everyone likes them. What changed in the last forty years? Why does DP make sense now when slaves didn't make sense for most roads in 1980?

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Posted by rdamon on Monday, December 20, 2021 11:55 AM

Long live the snoot nose SD40-2!!

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Posted by ns145 on Monday, December 20, 2021 12:41 PM

timz

Radio-controlled helpers with no engineer have been around since the 1960s anyway, but they were never widespread. In the 1970s the necessary equipment was on the engine -- no need for a separate radio car. But slaves still didn't spread -- SP tried them but didn't bite; UP tried them but didn't bite.

Now everyone likes them. What changed in the last forty years? Why does DP make sense now when slaves didn't make sense for most roads in 1980?

 

Back in 1980 railroads didn't have AC traction motor locomotives with starting and continuous tractive effort ratings of 150,000-200,000 pounds.  Three AC loco's on the head end of a train at full tractive effort can come very close to exceeding the strength of the coupler knuckles and/or stringline a train on a tight curve.  In order to extract the productivity benefits of AC traction, railroads had to move the third (or fourth) locomotive to a position either in the middle or on the rear of a train in order to spread out the tractive effort of the locomotives.  They mastered this with coal and other bulk commodity trains in the 1990's.  The first primary application of modern DP technology was on Powder River Basin coal trains.  DP enabled railroads to increase train lengths with 3 units from 100-110 cars to 135 cars or longer.  Now with P$R, they are applying the same technology to run super long intermodal and manifest freight trains.  Pre-P$R, most intermodal and manifest trains were never heavy enough to benefit from DP technology.  Historically, these types of trains depended more on horsepower/ton ratings to ensure that they could run at maximum track speed.  Now that practically everything is a land barge, maximum tractive effort is the limiting factor.       

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Posted by blue streak 1 on Monday, December 20, 2021 3:17 PM

May we wonder that maybe operation of a DPU unit(s) is subject to stray commands?  Coud that be why some trains are having pull aparts. Would a stray command of 3-5 seconds be possible to cause a few of these break aparts.?  Maaybe road foremans just check the lead loco for  commands and not what the DPU received?

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Posted by Overmod on Monday, December 20, 2021 3:25 PM

A part of this is the development of semiconductors and electronics to make reliable, programmable equipment and controls safe and cost-effective.  Another part is the railroads having the revenue to spend on equipping sufficient units to allow reasonable operations; some of the cost might be co-assigned to mandatory PTC installation... 'if you're installing those systems why not put DPU equipment in while the locomotive is disassembled for service?'

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Posted by BaltACD on Monday, December 20, 2021 3:37 PM

Overmod
A part of this is the development of semiconductors and electronics to make reliable, programmable equipment and controls safe and cost-effective.  Another part is the railroads having the revenue to spend on equipping sufficient units to allow reasonable operations; some of the cost might be co-assigned to mandatory PTC installation... 'if you're installing those systems why not put DPU equipment in while the locomotive is disassembled for service?'

I can easily be mistaken - with CSX I don't think DPU installations were put on any non-DPU equipped units when they had their PTC equipment installed. 

As I have previously stated, all new power that CSX was getting from approximately 2010 onward were equipped for DPU and also the form of Train Control that existed on the RF&P and some other subdivisions on the system.

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Posted by SD70Dude on Monday, December 20, 2021 3:57 PM

blue streak 1

May we wonder that maybe operation of a DPU unit(s) is subject to stray commands?  Coud that be why some trains are having pull aparts. Would a stray command of 3-5 seconds be possible to cause a few of these break aparts.?  Maaybe road foremans just check the lead loco for  commands and not what the DPU received?

A remote will only receive commands from the lead unit it is linked to (other remotes linked to the same lead unit will also act as repeater stations and relay radio commands to each other).  

Comm loss is a normal part of daily operations, and I believe remotes will continue to perform the last command for 90 minutes after losing comm with the lead unit, then they go to idle.  The engineer can force the remote to idle by making a full service application of the automatic brake, even with no radio signal the remote will still see the brake pipe pressure drop.  And of course an emergency brake application will have the same effect.  Both of these actions will bring the train to a stop, and you can then diagnose the problem.  

A remote acting up does have the potential to cause train separations, but bugs in the system are a far more likely culprit.  

Improper train makeup and operator error are far more common causes of train separations.

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Posted by jeffhergert on Monday, December 20, 2021 9:00 PM

DPs in power maintain the last command for 90 minutes.  Then they will go to idle and cut out their brake valve.  In effect becoming a box car.  In dynamic mode, they will stay in dynamics until communication is restored.

A DP in power may go to idle and cut out their brake valve by just making a service application.  That warning appears on the DP operation screen.  Our instructions used to say make a 10 psi reduction, then it went to 20 psi to force (ensure) the DPs respond.

To force a DP in dynamics to go to idle, you need to stop and make an emergency brake application.  Then they are supposed to go to idle and cut out their brake valve.  

I think part of the reason distributed power (Locotrol III) became popular is the softwear that automates some of the handling of the DPs.  Looking at instructions from the Milwaukee Road's instructions for remote helpers, air brake operation (automatic and independent) was done manually.  Now it's automatic.  The DPs follow the air brake commands of the lead unit.  No more separate buttons for air brake operation.  Current DP can also control up to 4 separate DP consists.

Like dynamic braking, it's not just for mountains anymore.  DP can help out on the flat lands that are seldom flat.  Still, there is a limit to the stresses that equipment can take.  Too often everything is figured like it's sunny, 70 degrees, and all equipment is brand new.  Reality has a way of rearing it's ugly head to that idealistic view.

Jeff

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Posted by OWTX on Tuesday, December 21, 2021 11:02 AM

DPU v1 was manned helpers. Many of those grades were flattened by improving diesel technology, or they were just flat eliminated by post-war railroad and route consolidations.

Post war 263k cars beat the heck out of pre war m.o.w. practices. So track structure and technology had to catch up to the unit trains. And, as noted, Moore's Law eventually allowed for replacing analog technology with digital systems.

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Posted by timz on Tuesday, December 21, 2021 6:51 PM

jeffhergert
DPs in power maintain the last command for 90 minutes.

Is that a typo? 90 minutes, not 90 seconds?

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Posted by BaltACD on Tuesday, December 21, 2021 10:03 PM

timz
 
jeffhergert
DPs in power maintain the last command for 90 minutes. 

Is that a typo? 90 minutes, not 90 seconds?

Jeff doesn't make that kind of mistake when it comes to operating parameters.  While 90 minutes does SOUND like a long time - when you consider the point to point radio characteristics of a lot of territories in which railroads operate - 90 minutes can be used up rather quickly by a train in mountainous territory not going all that far grinding up or whinging down grades with high levels of curvature and virtually no 'line of sight' for radio contact.

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Posted by jeffhergert on Wednesday, December 22, 2021 3:36 AM

BaltACD

 

 
timz
 
jeffhergert
DPs in power maintain the last command for 90 minutes. 

Is that a typo? 90 minutes, not 90 seconds?

 

Jeff doesn't make that kind of mistake when it comes to operating parameters.  While 90 minutes does SOUND like a long time - when you consider the point to point radio characteristics of a lot of territories in which railroads operate - 90 minutes can be used up rather quickly by a train in mountainous territory not going all that far grinding up or whinging down grades with high levels of curvature and virtually no 'line of sight' for radio contact.

 

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Posted by Erik_Mag on Wednesday, December 22, 2021 9:52 PM

SD70Dude

Comm loss is a normal part of daily operations, and I believe remotes will continue to perform the last command for 90 minutes after losing comm with the lead unit, then they go to idle.

I wonder how well the inductively coupled radio system used by the PRR would bhave with respect to comm loss? One caveat is that te PRR system depended on having some sort of wire(s) paralleling the track, e.g. a code line.

Comments on what has been said about radio technology: Sending commands was not a big issue for master/slave being in radio range - I remember ads in a 1964 issue of Model Airplane News for multichannel receivers that would fit in a model airplane. What would take up room is that control logic that would handle the nasty corner cases such as loss of signal that are much more serious for a train than for a model airplane.

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Posted by BaltACD on Wednesday, December 22, 2021 10:35 PM

Erik_Mag
 
SD70Dude

Comm loss is a normal part of daily operations, and I believe remotes will continue to perform the last command for 90 minutes after losing comm with the lead unit, then they go to idle. 

I wonder how well the inductively coupled radio system used by the PRR would bhave with respect to comm loss? One caveat is that te PRR system depended on having some sort of wire(s) paralleling the track, e.g. a code line.

Comments on what has been said about radio technology: Sending commands was not a big issue for master/slave being in radio range - I remember ads in a 1964 issue of Model Airplane News for multichannel receivers that would fit in a model airplane. What would take up room is that control logic that would handle the nasty corner cases such as loss of signal that are much more serious for a train than for a model airplane.

For the past two decades or more - railroads have been investing in the removal of wire lines for either signals, communications or both.  What line wires the carriers have not removed themselve, wire theives have removed the wires for them.

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Posted by SD70Dude on Wednesday, December 22, 2021 10:37 PM

Using a cable along the telegraph lines or catenary to carry communications between the lead unit and DP remotes would probably get rid of terrain-related comm loss.  But it would also knock DP out completely every time snow, ice or trees fell on the wires and broke something.  And like Balt said the railroads have been neglecting or removing that sort of legacy infrastructure for many years now.

A better solution would be to switch to ECP braking and use the ECP cable instead, while keeping the current DP radio system as a backup in case of a train separation.

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Posted by jeffhergert on Thursday, December 23, 2021 7:08 PM

I think in some places out west in the mountains, they've installed repeaters at some locations.

Jeff

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