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DC or DCC? or The quest for the ultimate Multi-train system.

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Posted by Soo Line fan on Wednesday, February 28, 2007 5:41 PM

 SpaceMouse wrote:

What context are we talking here? Are we talking about construction or thinking a mouse might chew off some insulation? Construction is a matter looking at the last place you worked on providing you used good installation techniques. I admit that if a mouse chewed off my insulation on a 4 x 8 layout and the buss lines shorted, I'd spend some time scratching my head, but eventually I'd track down the problem even if I created power districts in the process.

But I don't see how either scenario would be different in DC as opposed to DCC.  

Because while on your layout a person would have to search the entire layout buss (potentially) until he found the short. You, or anyone else would have no clue where to begin. On a DC layout they would only search the affected block- a much smaller physical area of the wiring to search. 

I tried to give you some analogies to help you understand one of the few advantages I feel DC has over DCC.

Let me try again. You have a spur track that the feeders are shorted together. On a 4x8 DCC layout with one district it all goes down. No question right?  But where? Now on a DC layout that same short occurs. You turn off the blocks one at a time and you soon know it is confined to that track. The block narrows it down to a specific area before you even crawl under the layout.

Jim

 

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Posted by BRAKIE on Wednesday, February 28, 2007 5:09 PM
 SpaceMouse wrote:
 Soo Line fan wrote:

 SpaceMouse wrote:

 

Are we talking about the same issue? We are talking about shorting out the track? It seems to me that only a couple things short out tracks: an engine sitting on a turnout or a guy that sets a coke on the track. I've heard of few melt-downs where buss lines became fused.

 

I thought we were talking about the same thing. The wiring will never become "fused" or experience "melt-downs" as you call it if circuit protection is adequate. A short circuit occurs and then the breaker opens or your light goes on. 

Lets assume you do have a buss-to-buss short. Certainly within the realm of possibility. How would you find it and fix it on a 4x8 with one district?

Jim

What context are we talking here? Are we talking about construction or thinking a mouse might chew off some insulation? Construction is a matter looking at the last place you worked on providing you used good installation techniques. I admit that if a mouse chewed off my insulation on a 4 x 8 layout and the buss lines shorted, I'd spend some time scratching my head, but eventually I'd track down the problem even if I created power districts in the process.

But I don't see how either scenario would be different in DC as opposed to DCC.  

Both DC or DCC layouts can have wiring shorts..The idea behind blocks is to isolate or find a short..The  DCC "power districts" was also design for that reason..A 4x8 layout doesn't need to be over blocked. 3-4 blocks/power districts will suffice for these small layouts.

Larry

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Posted by BRAKIE on Wednesday, February 28, 2007 5:02 PM
 jbinkley60 wrote:

 Soo Line fan wrote:
Actually his topic can encompass a broad area:
 SpaceMouse wrote:

A discussion that frequently becomes a side bar for the "Should I switch to or start with DCC?" posts, is whether or not you really need DCC.


One part of DC that does not appeal to me is in my engine terminal. I have a lot of blocks to park locos in different areas and stalls. When I want to get to the engines in the rear I have to move the ones in front.
Would jockeying them around be that much easier with DCC?
Jim

Absolutely.  I mentioned this to someone else on a similar thread.  It isn't about just running multiple locomotives on a layout, with DC you have to account for all of them, whether they are moving or not.  Drop 20 locomotives on a layout with DC, even if many are sitting on sidings and then try to keep straight which block switches you have to change to move the right locomotive.  It can be done but it is challenging.  A large yard can be worse.  Or what happens when you park a string of locomotives together in a yard siding and want to peel the first one out for road service ?    

 

NO! It is NOT easier because you  have to address each locomotive as you move it..Its not easy on DC either because you got to find vacant blocks to park the moved engines ..In my experience and after being a hostler on a DCC layout I felt like a accountant by the time the session ended..The club layout was design for this type of operation,however, most home layout engine terminals are poorly design for DCC or DC operation which adds to the frustration.

Larry

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Posted by SpaceMouse on Wednesday, February 28, 2007 4:51 PM
 Soo Line fan wrote:

 SpaceMouse wrote:

 

Are we talking about the same issue? We are talking about shorting out the track? It seems to me that only a couple things short out tracks: an engine sitting on a turnout or a guy that sets a coke on the track. I've heard of few melt-downs where buss lines became fused.

 

I thought we were talking about the same thing. The wiring will never become "fused" or experience "melt-downs" as you call it if circuit protection is adequate. A short circuit occurs and then the breaker opens or your light goes on. 

Lets assume you do have a buss-to-buss short. Certainly within the realm of possibility. How would you find it and fix it on a 4x8 with one district?

Jim

What context are we talking here? Are we talking about construction or thinking a mouse might chew off some insulation? Construction is a matter looking at the last place you worked on providing you used good installation techniques. I admit that if a mouse chewed off my insulation on a 4 x 8 layout and the buss lines shorted, I'd spend some time scratching my head, but eventually I'd track down the problem even if I created power districts in the process.

But I don't see how either scenario would be different in DC as opposed to DCC.  

Chip

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Posted by Soo Line fan on Wednesday, February 28, 2007 4:37 PM

 SpaceMouse wrote:

 

Are we talking about the same issue? We are talking about shorting out the track? It seems to me that only a couple things short out tracks: an engine sitting on a turnout or a guy that sets a coke on the track. I've heard of few melt-downs where buss lines became fused.

 

I thought we were talking about the same thing. The wiring will never become "fused" or experience "melt-downs" as you call it if circuit protection is adequate. A short circuit occurs and then the breaker opens or your light goes on. 

Lets assume you do have a buss-to-buss short. Certainly within the realm of possibility. How would you find it and fix it on a 4x8 with one district?

Jim

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Posted by Vail and Southwestern RR on Wednesday, February 28, 2007 4:28 PM

I think that DCC, in its current form, is probably here to stay.  The interface between the command station and the trains is "fast enough", it is very tolerant of noise, and it has a pretty large installed base.  On the other hand, there is certainly lots of room for improvement on the user interface side, which is going to keep evolving for years.

I think the DCC method of distributing power and signal is really pretty clever, one big benefit over DC is that it provides full power to the rails at all times, allowing for more potentially interesting things at the train end in terms of lighting, sound, etc.  I think that a wirless interface to the trains would be nice, but the size requirements for this in the smaller scales are pretty challenging, and were even more challenging ten years ago.  I also think the potential for interference (chicken wire scenery, motor noise, other reflectors around the layout) would have made for a frustrating experience.

If someone is starting out I submit that DCC is simpler and quicker to implement, simpler to operate, and not much more expensive that a DC system that provides comparable (or as close as reasonably possible) operation.  In the case of an existing layout, there are lots of factors going into the decision to convert, and I don't think there is a one size fits all answer.

 So there!

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Posted by selector on Wednesday, February 28, 2007 4:14 PM
Laugh [(-D]  As long as I don't hear Betty White's voice saying, "I think I can, I think I can..."
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Posted by Jason-Train on Wednesday, February 28, 2007 4:12 PM

Chip, Selector, both great points.

Chip, It would concern me though if the design was put forth with that being the intent.  I'm not disagreeing with you as this is typical of corp. america however when a standards group is put in place, I'd like to think money isn't the primary agenda (pipe dream I know).

I would hope, err like to think NMRA is there to develop an extensible standards for MRR.

I think Selector hit it right, and I'd have the same concern.  I can run my "Trainz" app at that point though and the entire aspect of "hands on" becomes moot.  I would not look forward to the day that becomes reality, that would be a hobby killer in my mind. 

As for the half-modulated DC pulse, fair enough, but I feel my point remains.  There was no need to change it from straight up DC (or DC as it is on a non-DCC layout).  All that is being done in DCC is/was possible with DC before NMRA was created.  This goes to Chips point though and that thought gives me an uneasy feeling of what the NMRA is about.

I suspect DCC has a limited life time, this is my personal forecast and yet another reason I'm not doing it (yet).  DCC as it is today is great, but should a new "standard" come out that actually meshs with technology and doesn't re-invent technology is a real long term "here to stay" direction. 

I'm a "computer guy", every time I work on my layout and can't help but make the analogy of the transformer being my "hub", my rails being my "patch cables", and my trains as "computers".  DCC in effect has accomplished this but it has been done in what I call a bubble (proprietary).  Yet again a point to what Chip wrote.

Hmm, I wonder what would happen when my trains run Windows MR and a get a virus /chuckle

Re-rail Success :)

/ramble off

EDIT

Just realized I mis-read some of Selectors post.  To clarify I'd like to use a computer for things like turnout controls and throttle but I'm not sure how much of a hobby we'd have if all we did is watch a virtual train on our monitor instead of watching the "real thing" on your layout.  Although I could see how loading up a "program" that walks through your layout running a pre-defined course, etc. I guess that would be pretty cool.  But would the hobby turn into more of a "programing job" than MRR?

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Posted by SpaceMouse on Wednesday, February 28, 2007 3:51 PM

 selector wrote:
Chip, I haven't gotten around to replying to your question.  I would hope that we will eventually operate our train sets/layouts entirely with our PCs.   Instead of the DCC systems that we buy currently, we'll get a software package in whatever format replaces CD-ROMs, and a little plug-in of some kind, a peripheral, much like the mini-data recording devices that many of us carry with us in a shirt pocket or on a chain around our neck from office to office.  The trains will always have to have an onboard something-or-other, from a sound emiting device to a device that controls its electro-mechanicals.  In other words, it is an analog item we are wanting to enjoy, so there will always have to be something to make the analog behave increasingly more realistically.  At some point, though, I can't see any great progress beyond where we are now.  We will still be stuck with something like scales, with all their inherent limitations, not the least of which will be the physics of reproducing acceptable sound.  It will only be in virtual ways that we will enhance our experience, and that kind of makes me shudder.  The more real the experience, the less aware one is of what is happening around the body that can spell danger.  We'll need security systems of some kind to keep people safe from harm while they are in the spell, so to speak, of the holo-deck.

In a thread a while back, I suggested that a computer could track the location of an engine and through use of stereophnic sound regulation make the noise from a loco (or any ambient noises you wanted as well) appear to come from the appropriate spot on the layout.

I also thought I would get it to follow my brother around so that it played They're coming to take me away haha, very quitely inside his head when he was in the layout room.

Chip

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Posted by Soo Line fan on Wednesday, February 28, 2007 3:45 PM
 MTennent wrote:

But I must ask - which is easier, finding which of 200 blocks is causing a problem or which of 10 blocks?

Mike Tennent

 

Finding the block is one thing. Now find the short and fix it.

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Posted by selector on Wednesday, February 28, 2007 3:43 PM
Chip, I haven't gotten around to replying to your question.  I would hope that we will eventually operate our train sets/layouts entirely with our PCs.   Instead of the DCC systems that we buy currently, we'll get a software package in whatever format replaces CD-ROMs, and a little plug-in of some kind, a peripheral, much like the mini-data recording devices that many of us carry with us in a shirt pocket or on a chain around our neck from office to office.  The trains will always have to have an onboard something-or-other, from a sound emiting device to a device that controls its electro-mechanicals.  In other words, it is an analog item we are wanting to enjoy, so there will always have to be something to make the analog behave increasingly more realistically.  At some point, though, I can't see any great progress beyond where we are now.  We will still be stuck with something like scales, with all their inherent limitations, not the least of which will be the physics of reproducing acceptable sound.  It will only be in virtual ways that we will enhance our experience, and that kind of makes me shudder.  The more real the experience, the less aware one is of what is happening around the body that can spell danger.  We'll need security systems of some kind to keep people safe from harm while they are in the spell, so to speak, of the holo-deck.
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Posted by SpaceMouse on Wednesday, February 28, 2007 3:42 PM

Jason, 

The thread is right on track as far as I am concerned.

You have good point about TCP/IP and bluetooth. However, my first thought is that maybe it was intentional to keep the $$$ in the industry by creating a non-conforming standard.

Chip

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Posted by modelmaker51 on Wednesday, February 28, 2007 3:41 PM

a few comments

The people that put power drops every 3 or 6 feet on their DCC layout are the same people that would do the same on a DC layout. I had a block/cab DC layout with drops every 10 to 15 feet. When I converted to DCC it took all of 30 seconds to disconnect the DC and replace it with the new DCC system, I was running trains again a few minutes later. I think one of the biggest mistakes the DCC industry made trying to sell the technology was the "all you have to hook up is 2 wires" slogan. All that block wiring I did originally are now my power districts. The only additional work I had to do in this area was add the lightbulbs to each of those "old" blocks, now I know exactly which section of the llayout is affected when a short occurs.

One of the reasons I bought the NCE Procab system was that it already had a serial port built in (yeah, usb would have been better, have you tried to find serial cable lately?). Interfacing with my computer was also relatively simple and doing so has made the programing of locos much easier, (computer interfacing is the area that I think needs further development soonest).

I don't want to start this argument over again, (it has been discussed ad-nauseum), but DCC systems do not supply AC to the track, it is half-wave DC, (it just behaves similarly to ac).

As to the cost of starting up, yes it's not cheap, it costs about the same as a new computer, but then that's exactly what you're buying, have you priced an X-Box or any of the other computer gaming consoles lately?

But you can do it in steps. My MR buddy and I partnered up and split the costs. We decided on a system that could be expanded as the funds became available. We started out with the command station and 10 NCE decoders (@11.50 each), the next month we added 2 utility throttles and another 10 of those decoders. This gives a good start, later this year we'll get the RF base unit, followed by the conversion of the throttles to RF. And of course more decoders, (we have about 60 DC locos between us to convert), butnow we have 20 locos we can operate with and as time and money permits, we will start adding units with sound, etc.

In the long run DCC is no more expensive than DC, but admittedly the startup cost can be intimmidating if you try to do it all at once.

Well that's my 2cts so  far.

Jay.

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Posted by Anonymous on Wednesday, February 28, 2007 3:38 PM

"Any time you can break an electrical system down into many small pieces it is always easier to trouble shoot. Basic troubleshooting 101."

Basic Troubleshooting 102: The likelyhood of trouble in a circuit increases exponentially with the number of small pieces. 

Frankly, I've never seen this particular argument (short recovery and troubleshooting) against DCC - probably because a short is a short, no matter if its DC or DCC. If you design your system correctly, you can limit the effects of  a short and find the problem no matter the system.

But I must ask - which is easier, finding which of 200 blocks is causing a problem or which of 10 blocks?

Mike Tennent

 

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Posted by Jason-Train on Wednesday, February 28, 2007 3:38 PM
So it appears the thread has been de-railed (pun intended) Evil [}:)]
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Posted by SpaceMouse on Wednesday, February 28, 2007 3:33 PM
 jbinkley60 wrote:
 SpaceMouse wrote:

I don't see the computer interface as being that expensive. What I see is that the manufacturers have not yet decided that it is worth the extra $5 to put a USB port in their base units. (Let the customer run down to RS for the cable.) They are still in cost competition mode and don't see the future of software development using their equipment.

But this chicken or egg dilemma will be crossed and one of the manufacturers will put the interface into their base unit then they all will. Then we will be able to add the power of the PC to the layout. Add intuitive mind reading and Brakie won't feel like an accountant. Big Smile [:D] 

You can't buy a modern PC now that doesn't have a USB port already.  If you do happen to find such a rare item, you can get 4 port USB adapters for around $20.

I'm talking about DCC manufacturers putting USB ports in their base units.

Chip

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Posted by Jason-Train on Wednesday, February 28, 2007 3:33 PM

 Soo Line fan wrote:
Actually his topic can encompass a broad area:
 SpaceMouse wrote:

A discussion that frequently becomes a side bar for the "Should I switch to or start with DCC?" posts, is whether or not you really need DCC.


One part of DC that does not appeal to me is in my engine terminal. I have a lot of blocks to park locos in different areas and stalls. When I want to get to the engines in the rear I have to move the ones in front.
Would jockeying them around be that much easier with DCC?
Jim

Yes and no as I understand it.  With DCC you can control the throttle of every engine independantly.  So you could "charge" the engine in the back to move from A to B however it wouldn't remove the issue if you have your engines in dead ends and are looking to move the one from the back to the front.  I'll attempt a textual image

Tx = Trains

A and B = destination points

..... = the Rails

A.......T1..T2..T3

If you want T3 "in front", you see the problem already, T1 and T2 must be moved.

A.......T1..T2..T3.......B

If you want T3 to exit via B then DCC can do this and T1 and T2 would never move.

In DC once you apply power to the rail ALL the T's will move, DCC allows each engine to have a 1 to 1 relationship with the throttle.  Each train has it's own throttle of sorts.

Clear as mudd I'd bet

Just know each Tx will operate indpendant of other Tx's (or even have two Tx's operate in tandom, together, the rail is your oyster in a lot of ways regarding DCC)

Got a break at work so I'm on a bit of a posting spazim /evilgrin

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Posted by selector on Wednesday, February 28, 2007 3:32 PM
 pilot wrote:

>Not true.  When I get a short, only the one district experiencing the problem shuts down...the >rest of my system continues to function merrrily...my locos still chugg and move, just not the >one having the issues.

>If you are interested, I can tell you how that happens.

Dont you need extra electronics between blocks to prevent this?

No, all you need, again no difference between the two systems, is gapped rails where you want blocks/districts, and you can solder a taillight bulb in series into the sub-bus for that district. You could call a taillight bulb extra electronics, but they are far cheaper than a switch.

In my case, I have exactly four bulbs, one per module in my square layout.  If a bulb lights up behind me, I know to turn around and look for a problem on that module. Also, I can anticipate having the bulb repeat these indications several thousand times, just as they do in one's car.  I don't think switches that we buy for $6 are going to withstand several thousand throws...some may, but they won't have the life, in general, to compete with the bulb.

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Posted by SpaceMouse on Wednesday, February 28, 2007 3:30 PM

 Soo Line fan wrote:
How many feet of track is in each power district? As I said above blocks are much shorter runs. Some are only a foot long. Any time you can break an electrical system down into many small pieces it is always easier to trouble shoot. Basic troubleshooting 101.

That is up to you. I settled on 8 feet for our club layout.

Just because a light comes on it does not show you where the short is, only that you have a short. Now what do you do?

Usually it is just a loco on a turnout. Most of the time even with 20-30 operators there's only one loco on a turnout in a given power district.  

How many districts would you place in a DCC 4x8? A 4x8 DC layout can be broken down into 10-20 blocks. Very easy to track down within a couple feet of rail without doing anything other than flicking a switch. If you had a short in a house or car and it was designed with only 1-4 fuses / breakers how long would it take to trace out the circuits?

On my 4 x 8 I didn't bother. I pretty much knew when and where a loco or car was sitting on a turnout. But you can have as many power districts as pieces of track if you are a mind.

Now lets use the same home/car and use 20-40 fuses /breakers. You zero in on the area much quicker.

Trust me, I trace 12v shorts for a living.

Jim

Are we talking about the same issue? We are talking about shorting out the track? It seems to me that only a couple things short out tracks: an engine sitting on a turnout or a guy that sets a coke on the track. I've heard of few melt-downs where buss lines became fused.

Chip

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Posted by jbinkley60 on Wednesday, February 28, 2007 3:28 PM

 Soo Line fan wrote:
Actually his topic can encompass a broad area:
 SpaceMouse wrote:

A discussion that frequently becomes a side bar for the "Should I switch to or start with DCC?" posts, is whether or not you really need DCC.


One part of DC that does not appeal to me is in my engine terminal. I have a lot of blocks to park locos in different areas and stalls. When I want to get to the engines in the rear I have to move the ones in front.
Would jockeying them around be that much easier with DCC?
Jim

Absolutely.  I mentioned this to someone else on a similar thread.  It isn't about just running multiple locomotives on a layout, with DC you have to account for all of them, whether they are moving or not.  Drop 20 locomotives on a layout with DC, even if many are sitting on sidings and then try to keep straight which block switches you have to change to move the right locomotive.  It can be done but it is challenging.  A large yard can be worse.  Or what happens when you park a string of locomotives together in a yard siding and want to peel the first one out for road service ?    

 

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Posted by jbinkley60 on Wednesday, February 28, 2007 3:25 PM
 SpaceMouse wrote:

I don't see the computer interface as being that expensive. What I see is that the manufacturers have not yet decided that it is worth the extra $5 to put a USB port in their base units. (Let the customer run down to RS for the cable.) They are still in cost competition mode and don't see the future of software development using their equipment.

But this chicken or egg dilemma will be crossed and one of the manufacturers will put the interface into their base unit then they all will. Then we will be able to add the power of the PC to the layout. Add intuitive mind reading and Brakie won't feel like an accountant. Big Smile [:D] 

You can't buy a modern PC now that doesn't have a USB port already.  If you do happen to find such a rare item, you can get 4 port USB adapters for around $20.

 

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Posted by Soo Line fan on Wednesday, February 28, 2007 3:16 PM
Actually his topic can encompass a broad area:
 SpaceMouse wrote:

A discussion that frequently becomes a side bar for the "Should I switch to or start with DCC?" posts, is whether or not you really need DCC.


One part of DC that does not appeal to me is in my engine terminal. I have a lot of blocks to park locos in different areas and stalls. When I want to get to the engines in the rear I have to move the ones in front.
Would jockeying them around be that much easier with DCC?
Jim

Jim

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Posted by Jason-Train on Wednesday, February 28, 2007 2:45 PM

Perhaps I'm not recalling my basic model train eletric book properly.

A block is a section of isolated track

A cab is a throttle to control that isolated track

Is that incorrect?

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Posted by Anonymous on Wednesday, February 28, 2007 2:41 PM
Could you define a cab and a block?
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Posted by Jason-Train on Wednesday, February 28, 2007 2:28 PM

I"m using a DC only layout with several blocks and cabs and there are many things I don't like about it.

However DCC IMHO is cost prohibitive, this is more than likely a supply demand market / economics issue and DCC will become more cost effective but again IMHO it is too steep for me.

Regarding battery power, I don't think this is a good idea.  There isn't a battery that can supply enough "juice" for a long session, powering the rails is the only way IMHO.

The failure in DCC is the requirement to convert the rails to AC.  This was a design flaw from the get go.  The technology should have been implemented more along the lines of bluetooth or wifi as these are tested and true and going through constant technology improvements.  Why the NMRA felt the need to invent the wheel again IMHO was a mistake.

If DCC had been implemented like a TCP/IP network it would have made more sense.  There wouldn't have been a requirement to convert to AC.  We'd be using a technology that has global standards, etc etc.  You could control your train from a bluetooth smartphone :)

I'm not in any position to say DCC under its current itteration will fail however it has been pourly designed and frankly it doesn't appear the folks that did design it involved non-hobby technologists. 

DCC is WAY to freaking sensitive.  When I hear about how folks are putting in leads every 3 feet or more, that is rediculus (sp).  Compensation for dirty rails or poor design in wire, etc, again a mistake IMHO.  If you have to put in leads like that, it should say something about the technology.  I'd call a design like this one, crap.  You don't hide problems by saturating the condition with non-required components.  You do it right from design to implementation resulting in SOLID frameworks.  (That said perhaps I'm un-enlightend on why folks put in leads every 3 feet /shurg).

All that said, I have not read every page of the DCC NMRA PDF's or every publication so while I've said what I've said, perhaps I'm way off base.

that's my 2 un-DCC-educated coppers

EDIT

Before the thread gets hijacked, I wanted to say, this thread is about DCC as a technology, correct?  This isn't about DC / DCC blocks, or helping folks troubleshoot the solution.

I'd like folks to debate the point if DCC is the right direction, and/or if it is too late to change.  Perhaps I've mis-understood Chips initial post.  I had a few guys ninja post while I took the 3 hours to get this post done LOL (posting at work is not so easy :) )

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Posted by Soo Line fan on Wednesday, February 28, 2007 2:13 PM
 SpaceMouse wrote:

 Soo Line fan wrote:
One area where DC is superior is in short circuit detection. Diagnosing shorts in a DC system with blocks is much easier than DCC.

A DCC layout that will have multiple users can be broken down into power blocks that would each have their own booster. These blocks, or the single user home layout can be broken down into power districts that are simply independently powered sections of track.

If you place a $1 light bulb in series between the track and the power, when that area shorts, the whole system does not go down, the load transfers to the light bulb and only that small section of track is shorted. Obviously, the light bulb is a good indication which section of track has been shorted. No switches to flip for detection. Sounds pretty easy to me.  

How many feet of track is in each power district? As I said above blocks are much shorter runs. Some are only a foot long. Any time you can break an electrical system down into many small pieces it is always easier to trouble shoot. Basic troubleshooting 101.

Just because a light comes on it does not show you where the short is, only that you have a short. Now what do you do?

How many districts would you place in a DCC 4x8? A 4x8 DC layout can be broken down into 10-20 blocks. Very easy to track down within a couple feet of rail without doing anything other than flicking a switch. If you had a short in a house or car and it was designed with only 1-4 fuses / breakers how long would it take to trace out the circuits?

Now lets use the same home/car and use 20-40 fuses /breakers. You zero in on the area much quicker.

Trust me, I trace 12v shorts for a living.

Jim

Jim

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Posted by SpaceMouse on Wednesday, February 28, 2007 12:56 PM

 Soo Line fan wrote:
One area where DC is superior is in short circuit detection. Diagnosing shorts in a DC system with blocks is much easier than DCC.

A DCC layout that will have multiple users can be broken down into power blocks that would each have their own booster. These blocks, or the single user home layout can be broken down into power districts that are simply independently powered sections of track.

If you place a $1 light bulb in series between the track and the power, when that area shorts, the whole system does not go down, the load transfers to the light bulb and only that small section of track is shorted. Obviously, the light bulb is a good indication which section of track has been shorted. No switches to flip for detection. Sounds pretty easy to me.  

Chip

Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.

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Posted by rrinker on Wednesday, February 28, 2007 12:47 PM

 Bruce Chubb did DCC-like things with DC using the C/MRI quite a long time ago. basically the idea consisted of a cab per block, and computer switchign of said cabs to your throttle. You had to imput the starting block of each train and then the system 'followed' you around the layout. Not allt hat easy to implement, and there is a lot of hardware involved, not to mention software. Moving the 'throttle' into the locomotive ala DCC is definitely a better way to go.

 You hear a lot about how "DCC is complicated" I disagree strongly. You can now buy many different locos with the decoders (even with SOUND) alreasy in them - so forget 'complicated' installation. With the price of decoders falling, and the new ones able to operate just fine on DC, I think we will only be seeign more and more lcoos come with decoders already in them. The choice will not be "sound and dcc" vs "DC" but simply sound vs no sound, both versions capable of oeprating on DC or DCC with no changes.

 The next step is to have the factory DCC locos come programmed witht he cab number insteadof address 03. Then, operation under DCC  would be no more complictaed than DC. You could take the loco out of the package, set it on the track, and away you go. NO programming. People get scared when they see words like "electronic", "computer" and "programming" but there is no requirement for understanding any of that to use DCC. It's a black box, no need to really know what happens inside just to use it. How many people even have a clue anymore about how the car they drive every day works? 

 

                        --Randy
 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Soo Line fan on Wednesday, February 28, 2007 12:39 PM

selector
pilot

The biggest problem I see with DCC is lack of robustness. If one user runs his locomotive into a switch and jams, the WHOLE transformer block gets shut down...

Not true.  When I get a short, only the one district experiencing the problem shuts down...the rest of my system continues to function merrrily...my locos still chugg and move, just not the one having the issues.

If you are interested, I can tell you how that happens.

..or, maybe I am not understanding you?  You say there is a difference, apparently, between the two ways of operating in that in DC, nothing shuts down when a short takes place? 

Or are you saying only a block shuts down?  Well, see my initial comment above. No difference.

One area where DC is superior is in short circuit detection. Diagnosing shorts in a DC system with blocks is much easier than DCC.

If I understand DCC, you split up larger layouts into electrical subsystems or districts. How many depends on the load and size of your layouts as well as individual preferences. My small layout can be broken down into 20 sections or blocks if you will. Do DCC layouts have 20 districts? Does each spur have the ability to be shutdown electrically?

If I have a short on my layout I can tell if it is on any single siding by flicking a switch. I can break down the mains into 5-foot sections. Some blocks are only the length of a single engine by the engine house. Each yard lead has a block. It is very easy for someone with limited skills to find a problem when the circuit is so easily broken down. Of course a person can climb under a DCC layout and break it down electrically but there is something to be said about the blocks being diagnostic aids.

Jim

Jim

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Posted by Anonymous on Wednesday, February 28, 2007 12:34 PM

>Not true.  When I get a short, only the one district experiencing the problem shuts down...the >rest of my system continues to function merrrily...my locos still chugg and move, just not the >one having the issues.

>If you are interested, I can tell you how that happens.

Dont you need extra electronics between blocks to prevent this?

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