DC or DCC?

[Atlantic Central]

Bob,

May I recommend a good book or two? Paul Mallery wrote two great books on wiring that discuss all forms of DC and DCC and cover all the basics very well. He was a giant in this hobby until his death last year. His was an electrical engineer by profession and writes in a very objective, technically accurate and professional style.

His two books, "Electrical Handbook for Model Railroads - vol 1&2" are available from Carstens, the peoplewho publish Railroad Model Craftsmen.

To all,

I will agree with the discription of "with DCC you run the train, with DC you run the track", but will remind everyone once again, that can be both good and bad.

DCC makes you the Engineer, in a very intimate way. If that is your only goal or even your main goal, than DCC is most likely for you. It also generally assumes "walk around" control as part of that intimate relationship. There are times when I like walk around control, thats why I use wireless throttles, but I do not see it as the only way I want to operate my layout.

BUT, if you want to run a big system of two or three or six trains all by your self, or if you want the flexiblity to run your layout several different ways, or you want signaling, detection or CTC control, or you have lots of hidden track in your layout scheme - you may want to understand the added costs and infrastructure needed to do these things with DCC.

Truth is adding any of the features listed above to DCC is just as complex as adding those features to DC and often much more costly. Running the track actually gives you some advantages for many of the goals listed above. Any kind of automation, or semi automation or even simple collision avoidance is much easier/less expensive with DC.

Again it gets back to style of operation. I feel many of you have not seen layouts operated in these other methods and therefore do not fully understand the why or how that would make someone want to operate differently from what you are doing.

As a long time modeler who has been exposed to lots of layouts with lots of different control schemes (DCC and DC), I am not "locked" into the current fashion trend of walk around control - in fact, sometimes I love to just be a railfan and stand in the same place and watch the train. And I want to be able to do that on my layout without inviting twelve people over to run the trains for me.

Example - I model a large Class I system in 1954, 13 scale miles of double track, stagging for 25 trains, train lengths 35 cars+ (18-20 actual feet). I need and want detection, signaling and colision avoidance, 6-8 trains will run at once, with or without a crew of 6-12 operators. My layout room is 22' x 40'. My goal is to model a small section of a VERY BIG railroad and for it to look busy as trains come and go. I also want to be able to have "operating sessions" with a crew of operators - I want both, an operation layout and a display layout.

IF I where modeling a small branch line, single track main, no hidden stagging, two or three trains a day like the Ma & Pa - in my same layout space, there is a high likelyhood I would use DCC. Its a different kind of railroad, with different operating goals from both a model and prototype stand point. DCC would have many advantages for such a layout - but that layout would not need 150 powered locos either, or train detection for 25 stored trains in stagging.

Sheldon

[hgcHO]

" I'm not knocking the DCC turnouts but I don't need them, I can reach the Caboose Ind manual throws or add a couple of leads for a remote switch.  I admit to being intrigued at first, but decided against them."

My first post, I had mentioned how I enjoyed the DCC turnouts and you being only one who replied; that you would considered them

Crazy how each one of us likes or dislike different systems but then that is being human. 

As for the DCC turnouts - that is what make the DCC work so well for me.  I helped my Dad set up a HO system back in 1949 where we ran wire from solenoids  to toggles switches.  So when I discovered DCC did this with no wires, I dove in again after almost 60 years.  Glad I Did.  Having Fun

Just my dollars worth. 

[Yampa Bob]

HO:  I remember your post, and yes at the time I was seriously considering the DCC turnout.  I am just having second thoughts which is very normal for me. 

I intend to buy a good book on wiring, just haven't decided which one.  Atlas has some, Carstens has others as you mentioned. I want an advanced book, not one that starts out with 2 chapters on electrical theory, how to solder and wire gauge ampacities.  Due to vision problems, I want lots of diagrams with as little text as possible.  In other words, "Don't tell me, show me".  Schematics rule, text drools.

Gene: I'm starting small with the intention of expanding. (it's a matter of age and expected longevity )  I don't, as yet have the length needed for "pass and meet" sidings.  I don't really want double tracks, I figure if one train looks dumb going in circles, 2 loops just doubles the dumbness, right?

My goal will be a mainline from Denver through the Moffat Tunnel, to Grand Junction, with the branch line I now have serving several towns and our ranch.  I'm remodeling my office/shop in the garage, and that will give me a 12' X 20' room.  That will be the point where I have to make some hard decisions. I don't like "shoulda, coulda" so I plan my projects years in advance.  Of course the older one gets, the more urgent the project.

I have a few more questions and comments but will stop here and add later. I'm pasting all these great comments into a pdf when I get the software.

Bob

[Atlantic Central]

Bob,

Trains may look dumb doing circles, but they look just as dumb only going 10 or 20 times there length and stopping and having to be turned, reconfigured.

I am a big fan of continious running with hidden stagging to get that sense of the train entering and leaving the modeled scene. One train enters, runs through the modeled scene, then exits to the stagging. Another, from the either direction, enters and passes through, etc, etc. Stored trains appear, some stop, get switched, etc, then leave, other just pass through, just like the real railroads.

Much more realistic than point to point runs that are too short to be realistic in my opinion. I model only one of each major feature on my layout. One large yard, one engine termnal, one large city, one large pasenger termnal, etc.

Sheldon

[Yampa Bob]

Sheldon: Good points, and I agree.  I'm beginning to see why layouts, small or large use visual barriers to give the illusion of time like park a train in a tunnel or blind, then have it reappear later. I plan to use natural barriers like mountains, dense trees and such.

Someone mentioned "speed matching" which brings up another scenario I am working through with both DC and DCC.

I like to run 2  UP or Rio Grande diesels with 10  RG, UP, and BNSF coal cars.  The real ones are usually 3 front, 4 in the middle back to back,  and 2 reversed at the rear, with 100 cars between. (empty 2 front, loaded 3 front)  I just run one leading, another rear.  Never mind turning the rear one around for now, this is a speed, not a proto, concern.

I put just the locos on the track 1/2 lap from each other and run full throttle.  Fairly well matched, but after about 20 or 30 laps, one catches up to the other. In my mind, I'm thinking there is no way to match them precisely in a consist. 

If I put the faster one up front, it's dragging the rear one and couplers are tight. Put the slow one front, and the rear is pushing, and all the couplers are slack.  The latter actually caused one car to uncouple on a curve and derail.  Even the more precise Kadee has more slop than a real coupler, right?

In a real consist, the engineer has control of all the locos with rpm and load sensors so all engines are balanced. Hit a steep grade and maybe the rear unit increases as needed.  I don't know hoot about real trains, I'm speaking theory and with some reading.  Please don't go off on a tangeant on this, like to stick to the main issue.

Ok, with DC I'm just stuck with a little speed difference.  I usually just put the faster one up front, causes no damage to the rear, the front unit may be a bit noisier with the load and run a little warmer, but at least the couplers are tight. Easy, hook up and run them, forget any slight mismatch.

The only way I can see doing better with DCC is to put the locos on the track and fiddle around matching the speeds (if I can adjust CVs) so they will run several laps and maintain exact interval at the same exact throttle setting.  This requires having each loco on a separate address, then when consisted having them both on the same address.  There is still no guarantee of precise matching in the final consist under all load conditions.  Is this really worth the effort?   

Bob

[Atlantic Central]

Bob,

You will never be able to match them so close that you can just "let them run". Everyone I know who does the pusher thing with DCC has two engineers on the train, each watching his coupler slack and ajusting his loco as needed.

With DC I only do multiple units at the front, as long as they are close in speed, no problem.

I know about the prototype situation you are refering to, but I don't know anyone modeling it.

Sheldon.

[Yampa Bob]

By prototype I was referring to having the rear engine reversed. I model this because it is the way coal trains run here.

I have a 10' test track here in my shop, DC powered.  I placed 2 Bachmann GE 70 DCC Equipped  on the track, both heading the same direction about 3' apart.   Turn the knob they both move forward.  Flip the switch they both move reverse. 

I turned one loco around, so that the two were tail to tail and turned the knob. The  one pointing forward went forward, and the reversed one followed right along in the same direction, as it should.  I just wanted to reassure those with questions about the compatibility issue of Bachmann DCC locos on a DC track. 

However, if I hook the EZ Command to the track, then I have to reprogram the loco, since forward is forward regardless of orientation.

So with DCC equipped locos running DC, I still have prototypical coal trains by doing absolutely nothing. 

I don't want to beat this issue to death.  At this point I have no further input to offer or questions to ask, just need to get some more good books and study.

I greatly appreciate everyone keeping their posts friendly with factual comments. I don't see this as a contest to prove who is right and who is wrong, and this thread proves that something can be debated peacefully.

For now, I'm calling it a "draw", leaving it up to personal needs and preferences. 

This issue pops up frequently as new people are drawn into the hobby. I would suggest that when it does, simply have them do a search for "DC or DCC?" Meanwhile feel free to add new information to update the thread.

Thank you

Bob

[Atlantic Central]

Bob,

To be just a little more specific, I would be affraid of derailments with cars between the two locos, DCC or DC. I have never seen that successfully done on a consistant basis.

Making the cars heavier would make in more reliable, but would reduce pulling capacity.

On one of the layouts in our local group, we do a train similar to what you discribe, with a loco on each end, facing in oposite directions, but it is only a switching run and it is DCC, two engineers each running their loco work together to run the train on two seperate addresses.

When we have done simple "pusher" operations on other layouts, that too is done with seperate engineers on each "set" of locos, and it can be tricky.

These are operational challenges that even DCC does not completely solve. I will admit that if your goal is to play engineer with your buddy and pretend you are the two engineers taking the coal grag over the mountain, you can learn to do it with DCC, but it is niether easy or automatic and defenately not designed for unattended display running.

I personally skip this prototype practice on my railroad as we are mostly in the fast freight business. Shorter faster trains with lots of power on the head end - much more model friendly, DCC or DC.

To simulate such operations for constant display running, some modelers in the past have used dummy locos simply pulled by the train to simulate the mid train or rear end helpers.

Sheldon

[hgcHO]

Good idea Sheldon, for simplicity  "dummy locos simply pulled by the train to simulate the mid train or rear end helpers".

How often does one find two different locomotives that run at the same speed on one DC controller?  Just asking for my own basic knowledge?

[Atlantic Central]

hgcHO,

Actually, many of todays newer locos run at similar speeds on DC. I'll give a few examples from my own railroad. I have no problem double heading the following:

Bachmann Spectrum 2-6-6-2 with Proto 2-8-8-2

Athearn 2-8-2 with Bachmann spectrum 2-8-0

For me, since I model the early 50's, most diesels where still matched sets like EMD F3's ABBA or Alco FA1's ABBA, etc or 3 matching EMD GP7's, so as long as they are the same brand, they run together fine.

A small speed difference in not a problem, just so one loco is not truly dragging or pushing the other.

Sheldon

[Yampa Bob]

I only had one car derail using the consist as described, turned out to be a defective knuckle spring and vertical slop.  Other than that, I run the setup both directions, often full throttle with no problems.  Keep in mind I'm only running 10 coal cars.  I did, however try it with 20 assorted cars for long periods with no derails. 

The couplers have to be adjusted precisely with no vertical slop, to prevent what I call "camming" decoupling, where one knuckle tries to ride up over the other.  This can happen in both pull and push situations.  I think this is one item that is often overlooked by modelers when checking with the height gauge.  It takes some judicious shimming, but I do not allow my couplers to "hang".  You can actually see the camming action on a test track by pushing or pulling 2 coupled cars.

I also make sure the coal cars are properly and uniformly weighted, usually a bit more than the usual, using a digital scale.   

Others may disagree with my picky methods, but it works for me. The key is turning "consist" into "consistency", which does require some fine tuning.

All my locos are Bachmann, and they seem very well matched.  At slow speeds, I have tried to observe coupler action.  Actually my wife does it while I vary speed as her eyes are better than mine.  Sometimes the couplers are compressed or extended, and sometimes seem to just "float" along. 

I think I owe the success of operation to Bachmann locos, near perfect trackwork, proper weighting and precisely adjusted Kadee couplers. All my cars have  been converted to Kadee.   I believe it was Sheldon a year ago who convinced me to make the switch.  Thanks Sheldon.

Bob

[WoundedBear]

Would decoders having BEMF make this type of consisting easier or more difficult? Would one regular decoder and one BEMF work? Would having both engines using BEMF be the trick?

I'm almost thinking that the fact they both can adjust their speeds a bit that 2 units with BEMF might work.

I could see where a regular decoder up front and a BEMF decoder as a pusher could cause trouble. If the lead loco slowed the BEMF unit would think it should "power up". But what if the lead unit is BEMF and the pusher is regular decoder?

Would using a shelf type coupler help?
http://kadee.com/htmbord/page119.htm

Sid

[Yampa Bob]

Sid
I have considered the 119, and may order a few in to try out, however I'm having good success with the #5 so far. (#148 )

Since I only have the EZ Command I can only program the rear unit for direction. I ran several tests and don't see any difference between  DC and DCC for the type of consist I am using. 

Before I started railroading, I visited a LHS for information and was told that everyone was going to DCC.  However, I noticed that most of his inventory was DC. Questioning his credibility I decided I needed further research.

My concern is that new modelers seem to be jumping into waters way over their head,  leading to frustration and dropping out of the hobby. 

Bob

[DaveS]

Perhaps my experience can help with your decision.
I got back into MRR after a 45 year break. I was a train nut as a lad but then in my teens other interests took over. I understood DC as I had  block control on the little layout I built when I was 12.
When I got back into the hobby, I wasn't entirely sure I wanted to invest a lot so I just went with DC as I was familiar with it and from reading some forum discussions on DCC it seemed very complicated what with talk of hexidecimals, etc. Besides I wanted to use my Penn Line Consolidation that I had taken out of retirement. In fact it does work but it isn't very smooth or well detailed compared to modern locos.
I built a small 4x8 layout with block control and it was fine until I discovered sound and found that I couldn't adjust it or control it well with DC.
I then went to a combination set up with DCC as Cab B. That worked fine but I was not happy with the performance of my Atlas TruTrack and found that in DCC any problems were maginfied.
I then decided to go all DCC with new track( Kato Unitrack) and a new layout
as I was using the DCC far more than the DC.
I found that in fact DCC is better on a small layout as you can stop several engines on one siding. Also the wiring is far simpler as there are no blocks and only a couple feeder wires are needed. I did as Gene mentioned and have my small service yard isolated from the rest of the layout with a simple on/off switch as even 3 or 4 sound engines all starting up can be annoying.
I usually only run one engine at a time and I like the idea of controlling the engine and not the track.
I agree that if I had a large fleet of DC locos I doubt that would want to convert a large number of locos. Also the control with the MRC power pack I had was nice. I'm using a MRC Prodigy Express and have found it very easy to use and programme CV's.
I hope that helps in some way.

[Len]

Some folks mentioned "simplified wiring" as a plus for DCC. After helping a neighbor with a 12x20 basement layout, I'm here to tell ya' even with DCC put electrical blocks in your trackwork. Just leave them on all the time.

Trying to find in all that track, without being able to isolate sections, where a dropped foam pin landed after taking a bounce is a major pain. Finally found INSIDE the factory building across the spur that goes into the building where the overhead crane is.

Len