DCC bus wires - full loop?

[Vonzack]

All this animosity over 2 wires!

 

MIke.

 

Poles apart it seems

[rab]

Poles apart it seems

Sounds like we're heading for a short circuit.

2 negatives coming together and sparks flying.

[Sir TophamHatt]

I'm now wondering if I've done the right thing going DCC I haven't started wiring yet but it looks SO complicated I thought it was to make wiring simpler?

Got a nasty feeling my large layout could end up a diorama!

 

• I run a loop under my baseboard because I have a basic oval (with a few extra bits).
• I've connected wires to [the bus wire] using suitcase connectors, sometimes two or three wires coming out of that to the track.
• I don't have any "filters" or anything like that.

 

I think a lot of these "senior" members, while being very knowledgeable, are at the stage where they can tinker and expand the wiring, hence some of the squabbling.

I've ran mine for over a year with no decoder resets, no shorts, no problems.

 

Unfortunately there is no hard facts of what is "best".  Some people have a loop, others have two or three lines, some people have their bus wires in stars - all depends on your layout shape but so far, it seems sensible to let the track shape dictate what shape the bus wires should be.  If it's an "out and back" rectangle, go for two lines, chocing the ends.

 

Lastly, it's not brain surgery, it's relatively small currents that just need to get to the track.

One member I spoke to here says they run DCC and have ONE connection to the track.  When laying, they made sure the track was all new and in great condition.  They don't understand this bus wire this and that business.  They said some people almost had some sort of breakdown when it was mentioned.

[JST]

I also know someone who has just one connection the the layout. Worked perfectly.... for about a year. Then the rail joiners started to give bad contact with the usual ensuing problems.

[F-UnitMad]

I have an O Scale oval, with sidings off, etc. DCC control is by NCE Powercab with 5amp booster. It's all one 'power district', & at most might have 3 locos in use at once - more usually, just two.

I had read of possible problems with using a continuous 'ring main'-type bus, so fixed my bus (actually twin+earth household wiring cable) under the layout with a break in it on one side of the oval. I then also put isolating joiners in the oval of track itself, at the same place, & made sure the droppers from rails to bus were on the correct 'sides' of the gap, so that the track itself isn't a continuous ring either, electrically speaking.

The actual power is connected on the other side of the layout, so more-or-less halfway along the bus.

I have no 'filters' or 'terminators' or whatever at the ends of the bus, & I have absolutely no idea even if the measures I have taken have made a blind jot of difference, but happy to report that it all works just fine.

[WIMorrison]

my last layout that I controlled with a Lenz unit had 2 wire connected to a loop bus under the baseboard. the track was connected to the bus through droppers and all points (14) were connected to that same bus.

 

No issues with anything, never ran out of power though I only ever had 4 locos working at once, all points switched correctly.

 

some people like to make it seem complicated, but the real skill is in showing how simple it can be - actually that is true of almost everything in life

[Revolution Mike B]

It's interesting reading through the comments on this thread as I have one continuous single bus for both locos and accessories, over a 20'x9' layout, and it all seems to work perfectly using an NCE Power Cab running a 2 amp power supply.......apart from one strange thing. I have one loco that when it's on the opposite side to the power feed, the horn won't sound. I've never heard about any issues with a continuous bus though?

[Phil S]

A lot of the differences in performance relate to the differing sizes (both gauge and extent) and locations of layouts ... permanent or transportable too.

which is why answering manny questions is like asking how long is a piece of string ? In 00/H0 our layouts have protected sub-districts, but not in G.

 

We have a loft layout (<10 years) - but that is now in a fully-insulated loft conversion, unlike the previous  40+ years in differing houses and temperature ranges!  It is 00 and DCC (It was Zero-1 until about 10-15 years ago) 

As Zero-1 it was '1 large circuit' with accessories on a separate bus.  IN DCC it became 2 then 4** Power Districts with PSX breakers and Rrampmeters for each.  (**originally designed for a central ZTC511+Booster @5A each, but replaced by Roco Multimice around the layout and 4 Amplifiers of 3.5A on SMPS supplies. with distributed 12Vdc@4A for LED layout lighting, and 12-16Vac for analogue point motors etc. Optical and RFid train/stock detection.

 

Track became ready-ballasted Rocoline Sectional Track instead of Peco flexible - Point motors take low currents and many are digital.- all dcc controlled Live Switched Frogs. 50+ dcc signals awaiting installation.  Only 1 problematical Peco Diamond Crossing because I needed the 24degree crossing ... this is where the auto-frog is going !!

The narrow gauge was originally going to remain analogue, but small enough decoders and adaptable decoders arriving - so it and the trams are all dcc.

Each 'board' (there are about 25+) may contain internal cross-linking between adjacent tracks in the same sub-district, fed from 1 bus connection for each district around the boards. Whereas with long flexible track sections in an uninsulated loft; the shorter 'sectional' sections do not suffer from 'rail creep'  and the fishplates are not contaminated by ballasting glue.  The lack of temperature/climate change seems to reduce dirt build up.  About 25 trains can be on the layout (most carriages illuminated , an increasing number of sound locos) drawing about 0.25-1.25A per district when stationary, and 4 00 trains might run at once (4 single track routes).  Controllers are now wireless versions for complete freedom of movement around the 8m x 5m

 

We also have a G_Scale garden layout This was mase MTS (LGB dcc) as soon as the original ovals were linked! - I was not going to rely on sectional switches out in the garden beneath willow and other trees, when the problem was gong to be maintinaing adequate power, after 30+years digital in the loft!

24 sets of points are all dcc controlled and there is ONLY 1 circuit: with multiple high current , low voltage flex supplying the dcc: HiPower Speaker cable.

Many joins are LGB fishplates - Copper or Graphite grease often being added at installation or maintneance. Many curved sections use Massoth Railjoiners which are screw-clamp connections which are also convenient for extra power feeds and paralleling of nearby tracks. Rail is LGB Code 332 Brass - a good conductor and no comparison to the smaller coder igher resistance Peco G Scale track.  The shortest/ most common track section is only 300mm ! (upto 1.2m) - and 'droppers are NOT wired to every section - or anything like it (neither are they oin the loft layout) - but adjacent tracks are paralleld to improve reliability.  Operating points and illuminated locos soon show any drop in supply with a dip in lighting when a point is operated IF there is a problem.  All my track is 'floating' in (peas shingle) ballast - nothing conreted !!  Current with 4-5 Sound trains running can be  5-6Amps and I use a Massoth Dimax800 with 2 wireless Navigator controllers (each can control 2 locos and operate points. They have a graphic display, one has illuminated buttons as well as screen (for after dark usage )  and are my ONLY controllers supporting 'Loco 0' analogue  operation.  All our stock is dcc fitted.

Diagnostics can include a dcc voltmeter at each end of the run (4GBP)

 

PORTABLY: We have 'modular' G_Scale Layouts made initially on hollow WICKES standard internal doors - THESE ONLY USE the Massoth Fisplates to link power between boards/doors - but they are sizeable screw clamps like in electrical connection boxes. INTERNALLY in each board/door, ALL tracks are cross-linked to ensure reliability of power feeds.  Some bards use Massoth Joines for EVERY join on the door/boad ( 70 on 1 3m  panel ) but a few places use the LGB fishplate - and these occasionablly need re-tightening, or replacement with a Massoth Joiner.  The Massoth joiners and tolerances also allow retraction of rails from the board edge to avoid damage in transit.  'Ballasting' is based on XPS or other foam infill with a 'stone' and/or grass 'topping' - heling keep the weight down. Basic scenic covering is foam topped with static grass.  Power is usually from a single Roco Amplifier - and is adequate even with several small steam sound locos ON THE LEVEL - but when set up on an inclined slope (as last September) this took the system close to the limit when the 4-motor Allegra unit was going 'uphill' on the 14 metre long version.

 

AND FINALLY - a Double (triple) deck Portable layout using the same style aluminium framed tables as our current loft layout wit XPS foam infill.

This lightweight layout stacks like an overgrown tea-trolley for transit (3m long x 1.5m high x 600mm wide). Track is Roco GEOline sectional track - agaion ready -ballasted helping keep the weight down.  1 Sub-district per 'level' protected by PSXs  with Roco Wireless Multimice +1 cabled handset. levels are inter-connected by a helix now transported deparately.  Automotive-type [AMP] plugs and sockets based on 6mm Spade Terminals are used for all board interconnections of DCC upper track, lower track and Midlevel/helix, as well as 12Vdc for LED lighting and ac (now mostly redundant - originally for LS150 decoders which were replaced by TrainTech DCC CDU modules running of the 'track' (accessory bus).   Within each board/'plank' of 3m or 1.5m length there are interconnections to parallel the track feeds  - again NOT 1 per sectional piece of track!  36 sets of dcc controlled points (now TrainTech CDU off the dcc accessory bus) Signals being added. Moving cars, and narrow gauges all controlled via DCC. As mentioned earlier - a separate Tourist/test loop (located insid ethe helix) [provides a visitor-operable railway or programming track woithout stropping the main layout.  To answer an earlier question /comment - YES I DO have to reprogram some locos during shows ! - sometimes they have just been bought.  I have multipage listings in text, or by pictures, of the DCC coders of ALL of my stock ... usually supplemented by writing the current set of trains numbers onto a scrap of cardboard !!

A VDU display on a 24" touch screen allows route selection and point setting to avoid errors due to the lack of real interlocking.

Other diagnostics: The Roco MultimausPro incudes Central Station Current Monitoring, as does the Massoth Navigator/Dimax for G.

All have been designed to be easy to maintain by identifying and resolving faults as easy as possible  - faults DO happen - I taught maintenance of equipment for many years !

[Crosland]

... a break in it on one side of the oval. I then also put isolating joiners in the oval of track itself, at the same place, & made sure the droppers from rails to bus were on the correct 'sides' of the gap, so that the track itself isn't a continuous ring either, electrically speaking.

 

A ring is created every time a loco bridges the gap.

 

Does the whole layout goes haywire every time a loco bridges the gap? I doubt it.

[F-UnitMad]

A ring is created every time a loco bridges the gap.

 

Does the whole layout goes haywire every time a loco bridges the gap? I doubt it.

Correct. No drama. No runaways. No magic smoke....

That's why I've no idea if the effort was really worth it!!