DPU EXPLANATION

[@AS-dv1oo]

In this video, how does 850 communicate only with the lead locomotive? What keeps trains passing by this train from interfering with the commands of the unit it is supposed to be hooked up with? I worked in the 70s when DPUs were nonexistent. I did see one once but it had an old B unit (F-series engine) converted to a radio car. I do know that all locomotives today are built with the electronics to allow a DPU hookup. It is interesting to see foreign engines (UP, BNSF)serving as a DPU to another tier 1 railroad engine, in this case it would be CSX.

[@nspokey]

NS always has helpers on the rear on mostly coal train. But on a long mixed freight they have DPU'S on mid train and manned helpers on the rear on the Pokey.

[@engineerpat5290]

oh yeah!!!

[@railfanjose2381]

I'll be keeping an eye out for those antennas but thanks for the info Pat

[@engineerpat5290]

YW

[@scrappycat1647]

I didn't begin noticing DPUs being used on the CSX A line until this past year. Now they seem to be used more often.

[@engineerpat5290]

Oh yes. They are used all the time!

[@gabrielkenny2054]

on the North end Subdivision , I only see end train DPUs on Coal

[@unity3596]

They have like 4 units on the coal trains on the north end

[@robleach7085]

What does the "slug" do?

[@byrd203]

what about LOco's that connect using the cable method where they use a big connecter and not wireless where its 2 locos connected togther via the cable what do u call that and can they use a DPU unit as a head end unit and head unit as a DPU can you explain this too

[@rc391995]

Jumper cables

[@rc391995]

And the answer to your question is yes if there was or is two consecutive DPU.s they was connected by jumper cable you can use anything as long as one of the DPU's was set up as a receiver loco except for steam of course. You could have SW 1500s back there or buttheads or whatever you prefer to call them.

[@rc391995]

Also you will find exactly what you are talking about on unit coal trains When they load or unload as the case maybe they just swap ends they operate from going back the opposing direction. I'm talking engine on front and rear of course . still hated the things though it m done.

[@clems6989]

Any info on the frequencies and type of signal used ?

[@engineerpat5290]

I do not understand

[@the_1drummajor]

I think he's talking about radio frequencies that the dpu's operate. You'll want to look at the 452.xxxx and 457.xxxx MHz bands. There are several DPU channels dedicated for this type of operation, and they're pretty close to the EOTD/HOTD frequencies (457.9375 MHz and 452.9375 MHz respectively). The transmissions that come out of these bands are packetized and use (if memory serves me correctly) Frequency Shift Keying in narrowband FM. There are software decoders out there that can decode the packets. None of the software out there have the ability to transmit (in case you are wondering about safety). With the software you can decode brake pipe pressure, battery charge, valve status, motion status, and market light status. Check out SoftEOT and SoftDPU out if you're ever interested in knowing more about decoding signals from trains!

[@rc391995]

Why would a rail buff need to know that ?

[@unity3596]

Can SD40s be DPUs

[@engineerpat5290]

No

[@alltrains2111]

No

[@unity3596]

dammit time to tell dovetail games that they added DPU to GP38-2s and SD40-2S

[@alltrains2111]

Sometimes they can

[@nathanrailfan4654]

DPUs Are Common On CSX.

[@engineerpat5290]

OH you know it!

[@nathanrailfan4654]

Manifests And Intermodels Are Very Common To Have A DPU.

[@billwest9110]

EngineerPat 5290 Even steam used mid train helpers and pushers in mountains. Lots of skill in those operations.

[@rc391995]

They wasn't radio controlled then now where they .

[@rc391995]

Mostly on flat ground there not as popular in the mountains. That is as far as the crew running them was concerned.

[@rc391995]

40 years ago they had them and called them RCU's Radio control units the RCU's had a RRC Radio Receiver Car . The RR slang term for those particular cars was called cracker boxes . everyone hated them they was pain in the neck to operate the signals wouldn't coincide from the lead to the RCU . Go through a tunnel the RCU would loose signal then you didn't know what the thing would do. They run a wire through t the tunnel that done nothing. Virtually when pass through tunnel the RCU had a mind of it own the thing might go to full throttle when the lead was shut down or it might apply the brakes as you was pulling lots of train separations and all sorts of stuff went on . if your train was in two different tracks in the yard and you was doubling your train together for outbound if the RCU WAS in the track you was doubling to you did at time found yourself in the situation that the slaves had shoved itself into the side of your train as you was doubling over. Slaves was RR slang for RCU . They got rid of them 40 years ago . the use of them now only cuts out jobs so the carriers will use them till someone gets crushed or they tear up more than they are worth . I've done seen where the DPU's as you prefer to call them has caused trains to shove cars ahead of the DPU off the track in extreme radius curves. 14000 ft trains and DPU's and extreme curves don't mix. Its like when you was a kid and you put all the cars you had on your train set behind your engine and the cars rather back in the train rolled over on there side because you had to much weight and the curve couldn't take it. They rolled over in RR terminology that's called to much lateral pressure . if you are a former its fun to you it wasnt fun if you was on the crew and got run off for it.

[@rc391995]

Former = foamer . sorry.

[@proudfoamer2]

Worse explanation of DPU'S operations ever. Let a professional do it next time.

[@engineerpat5290]

Thank you for the honest feedback. I am sorry I did not do as good of a job to suit you. I am 25 years old and been in this hobby for 22 years. I know many railfans through this hobby who have helped me be the railfan I am. If you have a problem with my content please leave my channel. I don't have the time or the patience to deal with comments like this. Thank you and have a nice day.

[@proudfoamer2]

@@engineerpat5290 just do a little more research on your topic next time. Google is your friend. From a retired railroader.