Power districts?

[SteamGene]

Probably terminology.  It seems to me that DCC is trying to be very PC since one of the original claims was "You don't have to divide your layout into blocks anymore!"  So instead its power districts and sub-districts. 
I will grant you that terminology can be very important, but it seems the only difference between a district and a sub-district is that one is powered directly by a booster and the other goes through a power manager. 
Gene

[jsmvmd]

Jim,

Thanks for the very good timely reply.

Just as in the experiment that shows why a 50# bag of sand will not be knocked off a plank by a 180 gr .30-06 bullet with 2500 ft-lb of kinetic energy, but easily pushed off by a small child, the answer is time.

Hunt,

As usual, a very precise answer.

Thanks all for very good info. Looks like my layout will be served with a PM-42 and sub-districts.

However, Hunt, is it wise to use this Digitraxx component with CVP or other mfr's components, or is that not an issue?

Best Wishes, Jack

[Jim Banner]

...  it seems the only difference between a district and a sub-district is that one is powered directly by a booster and the other goes through a power manager. 
Gene

Close, maybe half a cigar for this one.  A district is all the trackage that is powered by a booster.  A sub district is one of several divisions of a district.  Each sub district has its own power management.  It is unnecessary to divide a district into one sub district as each booster has its own power management built in.  So no, they are not equivalent except for a power manager.

The reasons behind districts and sub districts are quite different than the reasons for blocks on a dc railroad.  With DCC, the concern is providing enough power for all the trains without providing enough power at any one point to weld the locomotives to the rails in case of a problem.  Independent control of locomotives is inherent in the system.  With dc, the concern is keeping all the locomotives powered separately so that you can control them independently.  Power distribution is inherent in the blocking.  From an operational strand point, the major difference is where speed and directional control take place.  Imagine 10 men operating a DCC layout.  Each controls the power in his own locomotive (and only in his own locomotive) using speed and direction controls.  Imagine the same 10 men operating a dc layout.  Each controls the power in his own locomotive (and only in his own locomotive) by disconnecting the block of track on which his locomotive is running from all the other blocks of track and connecting that block of track to his own power pack (and only his own power pack.)  In the DCC case, all he has to worry about is speed and direction.  In the dc case, he has to worry about speed, direction, which block of track he is on, which block of track he will be on next, and whether someone else is already using his next bock.  Thus the expression - DCC is controlling your trains.  dc is controlling your tracks.

Question - a blind man walks into the middle of a model railroad operating session.  Without asking anyone, how can he tell in the first 30 seconds whether the layout is operated by DCC or by dc??

Answer - He just listens.  If he hears "look out, we're going to crash" he knows it is DCC.  But if he hears "who's got my block??" he knows its dc.

[Hunt]

Hunt,

As usual, a very precise answer.

Thanks all for very good info. Looks like my layout will be served with a PM-42 and sub-districts.

However, Hunt, is it wise to use this Digitraxx component with CVP or other mfr's components, or is that not an issue?

Best Wishes, Jack

Jack,
The compatibility of different manufacturer’s DCC components depends on the components, how you are going to using them and when they were made. So I suggest you ask each of the component manufacturers if there are any caveats to using one of their components with another’s. Some manufacturers will not give you an answer.

I am not aware of a significant issue to using Digitrax’s latest power manager with CVP’s command station or power booster (stay within the ratings).

With the exception of selecting a decoder, I suggest one use the same brand components as the command station until one has a very good understanding of the electronics involved.

[Hunt]

Gene,
"Close, maybe half a cigar for this one," wrote Jim Banner.

With a careful reading of the first paragraph of Jim’s reply you may realize when comes to electronics, especially some DCC components,  that sometimes, what appears to be the condition because it seems so commonsense obvious is in actual fact not the case. Some do find on the front leg of their DCC learning curve(s) having to deal with the drawbacks of assume. As you may now understand, it is not just the terminology. 

[jsmvmd]

Hunt,

Roger that. Will check specs and install as instructed by the mfr.

Best Wishes, Jack