Block vs District

[dbaker48]

What is the difference between a Block and a District?

Thanks

[Big_Boy_4005]

Blocks are generally used to assign a section of track to a power source. Districts are more of a power distribution method for the purpose of isolating shorts and current draw. Power districts are more closely associated with command control, where full voltage is always on the rails.

[FJ and G]

Just a guess, but block is used for conventionally wired layouts, usually with a panel and switches that control which trains go on which powered up segments of track (isolated).

Power districts are used for DCS and TMCC and DCC operated lines and are basically used in order to not overload any section of track with too much power requirements (such as long lighted passenger trains). Districts are arranged similarly to blocks.

That's my understanding, at least. Others will correct me I'm sure.

(just noticed Big Boy beat me to the reply)

[FJ and G]

Just to add something. One could operate conventional in one session and command control in another operating session and the wiring schemes for both block and power district could enable both methods to be used. On some layouts, btw, DCS requires a star wiring pattern.

[Big_Boy_4005]

I've got my "A game" going today Dave, super fast.[swg]

[lyle_styles]

Dave,

Is star wiring pattern where there would be a main wire looping around the layout and then tapping feeders off of that main wire to feed individual blocks or districts?

If I am really far off here, could you send me in the right direction?

Thank you
Lyle R Ehlers

[Birds]

The wiring methods are typically refered to as "topologies" - as in bus topology or star topology.

The big loop with the short taps coming off of it would be "bus" topology (also known as "racetrack" wiring to some phone installers in some areas of the country).

The star toplogy is also known as "home run" wiring.

With star wiring you have a feed from the transformer to a distribution point (a terminal or barrier strip). The power is split out at the distribution point and run directly to the desired end points.


In the picture above, the red wire in the upper right corner of the terminal/barrier strip comes from the transformer.

The copper wire on the top row of screws distributes the power from the transformer down the length of the terminal/barrier strip.

The red wires (and the one black wire because I ran out of red wire) on the bottom of the terminal/barrier strip run directly to different sections of the layout and connect to the track

Here is a quick drawing (click to enlarge):


In the layout, the short blue bars are meant to represent isolated track sections or blocks. You could do the same star wiring without blocks, just feeding power to various places.

The common wire does not connect to this terminal/barrier strip. If you felt there was a need you could set the same pattern up for the common wiring.

[Anonymous]

I call star wirng a "hub and spoke" distribution system and whether for conventional,TMCC or DCS I have all wire runs paired. But when I removed and sold my DCS system I reinstalled a buss-----a common and hots for all districts between my hubs.

[wrmcclellan]

Don,

Block is a specific section of track.

District may be an area of the layout fed from a single power source and may have several blocks in it.

Imagine if you had a 4' x 8' layout with two loops of track on it.

Each loop might have two blocks so you could power off one end of the loop or the other.

Let's say you use two Lionel TPC-300's and two PowerHouse transformers, one for each 4x4' half of the layout. These are your power districts.

Or you could use each TPC-300 and Powerhouse to feed each loop, these could also be considered power districts or each loop could be a block.

Which is best? Hard to say. Depends on the track plan of your layout and how you wi***o feed the power to it (feed an area or feed a loop of track).

Very large layouts like our club layout are usually divided into districts. Our club layout has 6; Roundhouse, industrial, city, yard, mountain1 and mountain2 districts so we can power a district down for troubleshooting.

Wish we had better blocks inside each district as the few times we have had a problem, it was only isolated to about a 20 - 40 ft section of track (each of 3 main loops) in a district. At the time we built the layout, the prevailing thought was we have TMCC and DCS, who needs block control? Well when you have an intermittent short and can only isolate it to 30 ft of track, it takes quite a while to trace it down.

While we are on the subject, make sure you plan sidings and spurs with isolated center rails so you can shut off power to parked trains. Lighted passenger cars can pull several amps of power and parked locos for several manufacturers are not always easy to turn off somke units. MTH locos shut down pretty good. Lionel Locos tend to shut down with lights on and smoke units running. One does not wi***o burn out the lights prematurely.

Regards,
Roy

[lyle_styles]

Thanks for the wiring info everyone.

Lyle R Ehlers

[cmrj]

Hi Don, Roy has the best definition of block and district from what I read in the I/O manual's.
Have a great day Mike

[Anonymous]

Basically a block designates a section of track that is isolated for control purposes. It is usually a throwback to conventional control where anything in a block is operating under control of a single set of controls for operating trains in that block. Power districts indicate isolation of sections of track to ballance electrical loads, aka so many watts are assigned to a given section. This type of terminology is usually used for command control operations where there is constant volatge on the track and trains are addressed and controlled by digital signals. A large loop of track could be designated as single control block but might have two or more power districts feeding it. This is very similar to the way a real electrified railway works.

While you could throw a single monster power supply at a layout and make one large power district there are distavantages and serious safety concerns. Multiple smaller districts make more sense.