How far apart are your main bus connections--are they really needed?

The books and forums suggest 14 gauge bus runs, soldered to the track every few feet with smaller gauge jumpers. If I solder all my joiners to the HO code 100 flex track I plan to lay down, are the bus runs even needed? The rails themselves are as large or greater than 12 or 14 solid wire. I can see putting bus runs in a few places, and across turnouts. This will be a DC only layout. Thanks to all for your advice.

The Nickel Silver track is a very high resisitance compaired to Copper!

You can do what ever you want

But you won’t be happy with the results!

BOB H - Clarion, PA

If you are going to have a DC only layout, you would not have a buss run anyway, if you are going block control. Your block control wires go to each block and you can daisy chain, your feeders to it.

I have a rather large DC 3Cab control layout, 12’1/2x40x12’1/2 that start out with 20 gauge stranded wire from the toggles, and rotary switchs to European style terminal strips for each block with 14 gauge stranded wire. Not one voltage problem in 25yrs and I will on occasion, run DCC locos with sound, without a hitch… Speaking from My experience.

Frank

The copper wire imposes about 1/20 the resistance on the voltage as does the NS “wire” being fed at intervals by it. The soldered joiners really help to ensure what voltage there is is not gated by the joiners, but it doesn’t mean the transmission along the rails and at the joiners is of great quality…in a manner of speaking. So, the idea is to ferry the voltage over distance via a material that won’t impede it so much, and then branch off from a more robust distant voltage with feeders. If you only feed the rails at point X and expect a distant point Y to enjoy the same voltage, you will be greatly surprised at how bad it has become. Personally, my maximum distance between feeders is 6 feet.

-Crandell

I just ohmed out a section of flex and got .3ohms, whereas the same length of 14g was under .1ohm. Resistance is accumulative in series, so the further you go, the higher the voltage/current losses. If you have a bunch of power hungry DCC sound locos, a few more feeders could mean the difference between a smile or a look of bewilderment as to why it’s not working when you get too far from the feeders

I agree with the others. While nickel-silver is a horrible conductor compared to copper, on a DC layout you should not need a bus at all. Worst case is the locos slow down a bit when they get further from the source of power. Even then simply adding one more feeder from the power source would solve that.

LION has 14 miles of track. The left rail is conected to GROUND, the Right Rail provides forward (+) or reverse (-) voltage from the bus. (Actually LION runs Subway trains and reverse movements are not permitted–so only + voltage is needed)

Because of automation, there are gaps all over the place, and so there must be a feeder between each station.

LION uses 10.2 volts for most of the mane lion, but has a separate 12 volt bus for the upgrade sections. (Speed is controlled by resistors embedded in the track system. : )

For Block control, your blocks should be sufficient, for other applications, the best practice includes using a bus.

Use a bus, it makes things easier.

ROAR

Make up your mind!! Should it be a bus or a subway?!?!

[8-|]

Agree that extremely long DC blocks you can do the same and supply the added length of the block w/ additional feeders (from a sort of buss for that block) Voltage drop will be minimal along the rails.

Our old club layout w/ 8 Cabs DC control was a total mess of “spagetti” under the layout from years of reclaimed whatever wire that would do. A never ending job of replacing bad/ worn DPDT. What a wonderful thing this DCC

The real reason for track power buses is to overcome non-conductive rail joiners. The inside of each rail joiner, where you cannot get at it to clean it, corrodes slowly over time. Sooner or later one rail joiner will corrode so much that it stops conducting electricity. Once that happens, all the track “downstream” of the corroded rail joiner looses juice and the train stops. Assume you are using 3 foot lengths of flex track. If you had feeders going to each and every piece of flex track you would have an absolutely bullet proof installation that would run every if every rail joiner opened up.

That’s overkill. If you think about it, each section of flex track has rail joiners at both ends. The rail will get juice so long as ONE rail joiner is still conductive. And, if you think about it, the rail joiners are reasonably reliable, it is unlikely that BOTH rail joiners will fail. So, if you provide feeders to every other piece of flextrack, every 6 feet, things will work reliably.

If you soldered ALL the rail joiners, then as you suspect, the rail would carry the power, just fine. But you really need to have at least a few joiners loose, to permit the track to move when the benchwork swells or shrinks as the humidity changes. If all the joints are soldered, and the benchwork moves, it will tear up the track somewhere. I don’t solder rail joiners,

Well, that was good information for me as well, as I’m wiring the extension to my small (2’X20’) along the walls switching layout for DC. I use cab, instead of block control. I was just wondering how many connections I will need for my bus for reliable operation and it looks like I’ll need 3 or 4 more feeders from my bus in order to make it work well. Thanks!

[quote user=“dstarr”]

Mister Mikado

The books and forums suggest 14 gauge bus runs, soldered to the track every few feet with smaller gauge jumpers. If I solder all my joiners to the HO code 100 flex track I plan to lay down, are the bus runs even needed? The rails themselves are as large or greater than 12 or 14 solid wire. I can see putting bus runs in a few places, and across turnouts. This will be a DC only layout. Thanks to all for your advice.

The real reason for track power buses is to overcome non-conductive rail joiners. The inside of each rail joiner, where you cannot get at it to clean it, corrodes slowly over time. Sooner or later one rail joiner will corrode so much that it stops conducting electricity. Once that happens, all the track “downstream” of the corroded rail joiner looses juice and the train stops. Assume you are using 3 foot lengths of flex track. If you had feeders going to each and every piece of flex track you would have an absolutely bullet proof installation that would run every if every rail joiner opened up.

That’s overkill. If you think about it, each section of flex track has rail joiners at both ends. The rail will get juice so long as ONE rail joiner is still conductive. And, if you think about it, the rail joiners are reasonably reliable, it is unlikely that BOTH rail joiners will fail. So, if you provide feeders to every other piece of flextrack, every 6 feet, things will work reliably.

If you soldered ALL the rail joiners, then as you suspect, the rail would carry the power, just fine. But you really need to have at least a few joiners loose, to permit the tra

Please explain your distinction between DC cab control and DC block control. I have always interpreted those two terms as synonyms and used them interchangeably.

Permit me to supply a few definitions:

Block: A length of track isolated for signaling or track power control purposes.

Cab control: A system using a selector switch for each block to connect it to the proper train controller (Cab.)

MZL: A system using contacts on point throwing devices to connect multiple blocks to a single directly powered block. One directly-controlled block allows a train to transit an entire zone, thereby sharply reducing the number of ‘cab control’ switches.

DCC: A system which allow all blocks to be connected to a common bus, depending on electronics to route the proper direction and speed (and other stuff) instructions to a specific locomotive.

So, back to the block. My longest control rail block extends along six meters of track. There is ONE feeder in that six meters, but all rail joiners have jumpers soldered around them. The common rail for that block is gapped at almost the same places as the control rail, with a single feeder. All common rail feeders connect to the common rail bus at the nearest terminal strip. I recommend this for ALL layouts, regardless of control system type. If there are multiple feeders to a single un-gapped length of rail, some could fail and you would never know (Until the last one died.) Likewise, if one shorts out, which one? One feeder between insulating gaps simplifies troubleshooting. OTOH, if there are no insulated gaps in a scale mile of track with a dozen feeders and something shorts…

I rest my case.

Chuck (Modeling Central Japan in September, 1964 - with electricals as bulletproof as possible)

[bow][bow] Good one!!

At Boothbay Railway Village layout, we add a feeder to every other piece of flex track, and solder the rail joiners. It is a good sized layout, and we run 3 or 4 trains when the museum is open.

I solder my feeders at every other rail joint and the joint is soldered as well. That means every piece of rail is directly wired to a bus so nowhere do I rely on current passing from one piece of rail to another via an unsoldered rail joint.

For what it may be worth I found no need for bus nor feeders on my past 1x12’ switching layouts…

I’ve seen some layouts that had wire overkill while others was staving for feeders yet both work equally well…