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Question re DPUs

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Question re DPUs
Posted by LithoniaOperator on Tuesday, February 9, 2021 10:35 PM

I watched the video of the monster UP train, and it sparked a question.

That train had three DP consists, each with two units. In those pairs, does one unit get the radio signal, and the other one is controlled by MU cables?

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Posted by SD70Dude on Wednesday, February 10, 2021 12:27 AM

Yes.

Greetings from Alberta

-an Articulate Malcontent

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Posted by MMLDelete on Wednesday, February 10, 2021 12:45 AM

Thanks, Dude.

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Posted by Max Karl on Wednesday, February 10, 2021 11:38 AM

As I recall, many UP SD70Ms weren't equipped with DP because of the large order and cost add-on. When used as DP they are MU-ed and controlled by the DP equipped unit with it. If a DPU system fails on a locomotive, will the other MU-ed locomotive automatically control the failed unit, or is only one DPU in a set linked at a time? 

  Max Karl, MRL and BNSF

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Posted by SD70Dude on Wednesday, February 10, 2021 12:51 PM

There can only be one controlling locomotive in a consist at any time.  If one fails you would have to go back there, set up the failed unit for trail, set up the other unit for lead and as a DP remote (if it is so equipped), and then return to the head end and re-link everything.  

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Posted by BaltACD on Wednesday, February 10, 2021 6:22 PM

I believe a DPU leader can only control up to FOUR DPU Trailers.  The number of locomotives in the leaders consist can be any number consistent with the carriers train handling rules; likewise the number of the locomotives in a DPU Trailer consist can be any number consistent with the carriers rules.

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Posted by mvlandsw on Wednesday, February 10, 2021 7:42 PM

What's the procedure for linking them up? Do you enter an id code for the remote unit like with an EOT?

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Posted by Max Karl on Wednesday, February 10, 2021 8:08 PM

Here's a video talking about setup for DP operations on the SD70MACs. Too bad my MAC manual mentions nothing at all about DP usage, a main feature about them! From what I can remember, the two units have to be within radio range of eachother. They use a special encrypted radio channel to prevent tampering. Knobs and buttons are turned in the cabs for one to lead in the consist and the other to be controlled. They then turn on the DP mode, look for the loco in the lead unit, and connect to it, inputing direction and how the engineer would like to use it. Then it's highball. I'm sure someone could give a more detailed explanation, but that depends on how much can be safely said. 

  Max Karl, MRL and BNSF

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Posted by Paul Milenkovic on Thursday, February 11, 2021 7:12 AM

Max Karl

Here's a video talking about setup for DP operations on the SD70MACs. Too bad my MAC manual mentions nothing at all about DP usage, a main feature about them! From what I can remember, the two units have to be within radio range of eachother. They use a special encrypted radio channel to prevent tampering. Knobs and buttons are turned in the cabs for one to lead in the consist and the other to be controlled. They then turn on the DP mode, look for the loco in the lead unit, and connect to it, inputing direction and how the engineer would like to use it. Then it's highball. I'm sure someone could give a more detailed explanation, but that depends on how much can be safely said. 

 

 

That's odd.  That the units in a DPU consist follow their leader through short-range radio signals, doesn't that mean they have a large portion of the DPU gear in them, all but the part to get longer-range radio signals from the consist at the head end of the train?

So you have some locomotives with the full DPU gear, some with only the gear to be in a remote DPU consist, and other units relying on MU only with no DPU equipment?

And would not all of the radio signals used in DPU be encrypted to prevent malicious tampering or spoofing from tech-savy railroad vandals?

Doesn't that make dispatching the locomotives for a train a nightmare of scrounging up the right kind of power for a train?

If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
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Posted by Max Karl on Thursday, February 11, 2021 7:37 AM

If a unit is equipped for DP, it has all the equipment required for all types of DP operations. All the receiver, transmitter, encoder etc. It wouldn’t make sense to equip one with only a transmitter and the other a receive. Some modern locomotives, like many UP SD70Ms, don’t have any DP equipment, but this is a rare case. 

Say there are 2 units used for DP, and both have DPU systems. Only one is connected to the head end through radio, the other is connected with MU to the radio unit, even though it has DP capabilites itself. 

The radio channel DPUs use is encrypted for all parts, not just the connecting signal. Finding motive power isn’t an issue, since trains that use DP have modern engines leading and distributed.

  Max Karl, MRL and BNSF

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Posted by BaltACD on Thursday, February 11, 2021 9:19 AM

DP equipped engines are a known commodity to those required to assign power to trains.

CSX was buying DP equipped engines long before they ever started using DP on their own territory.  I first noticed CSX engines having DP mentioned in their 'accessories' as early as 2013.  I don't think CSX actually started using DPU's on their own territory until 2017 - after I retired, however CSX power was being used in DPU operation by the Western carriers with the CSX units that ended up on the Western carriers from run through operations.

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Posted by jeffhergert on Thursday, February 11, 2021 4:44 PM

Some years ago, software upgrades now allow dp equipped engines to be linked up.  Often there'll be a UP lead with a foriegn line engine as the dp.

When linking there are two radio channels the system uses.  It's redundency in case comm fails on one channel.  The use of the channels is automatic, no input from the engineer.

Jeff 

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