DP- why so late to the game?

[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?

[ns145]

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.       

[rdamon]

Long live the snoot nose SD40-2!!

https://www.railpictures.net/photo/267233/

[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?

[Euclid]

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.   

[cx500]

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.

John

[Ulrich]

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. 

 

[daveklepper]

Thanks for the history.

[JayBee]

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.

[Gramp]

Thanks, SD70dude

[SD70Dude]

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.

[Gramp]

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. 

[blue streak 1]

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.

[jeffhergert]

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  

[BaltACD]

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.

[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.

[BaltACD]

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.

[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?