Benefits of Additional Power Feed Droppers on DC Layout

[Redford73]

My current layout in progress is a 12' by 8' continuous loop with two main lines which branch out into four at some points on an upper level and one main line which branches out into three and a depot yard on a lower level.

 

I will be using three of the output terminals on two 'D' Gaugemaster controllers (one for each 'main' line).

 

Is there any benefit in splitting off the feeds from the outputs so that each 'main' line section has power entering at two sections on the circuit or is it a waste of time?

 

I had a slightly smaller layout previously and just used one feed for each main line.

 

I have obviously already checked that the one feed location I currently intend to use feeds all parts of the relevant track circuit (sidings, loops etc).  

[cliff park]

How are your different sections of track joined electrically? Just fishplates, or droppers soldered and wired past the joints? Because think about why you would need extra feeds. If using just fishplates then other feeds would be good, but they need to be fairly heavy cable, or you'll have volt drops on a long run.

[Silver Sidelines]

Time to start thinking about Sections and Cab Control with a common return.  Most of my Sections equate to three or four lengths of track - one dropper to each rail.  So yes - I would expect your 12 x 8 continuous loop to have more than one feed - lots of feeds infact separated by insulating rail joiners and connected up to SPDT switches.

 

Regards

 

Ray

 

PS Just edited my post in the light of reading David's comments below.  'one dropper to each rail' = 'one dropper per Section to each running rail'.  English is very confusing.

[DCB]

Sections and or Cab control is definitely the way to go  even with DCC sectioning the wiring is a massive advantage when fault finding,

I use two pole rotary switches to select which controller feeds which section, leaving one spare position as "Off."

 

With intelligent positioning of isolators you can do most movements permitted under signalling regulations with DC cab control, I attach pilots and bankers and the only maneuver I can't really do is to have the incoming loco follow the ECS from the platform  which is something I have never seen on a DCC layout either

 

Droppers every yard or so really come into play with DCC and small section rail, I have 20 foot . almost 7 yard lengths of steel code 100 rail fed from one end only which have no discernible speed drop even five yard sections fed from a point through the point blade contacts with no problems using Variable voltage controllers, H and M Safety Minor and OnTrack controllers.   The big advantage of DC over DCC is the 1 amp overload cut out of most DC controllers gives fish plates and point blade tags a much easier time than DCC which can be up to 4 amps overload cut out and it is this high current which requires the use if multiple droppers to avoid damaging fish plates under overload conditions, partial short through a derailment etc

[Crosland]

The big advantage of DC over DCC is the 1 amp overload cut out of most DC controllers gives fish plates and point blade tags a much easier time than DCC which can be up to 4 amps overload cut out and it is this high current which requires the use if multiple droppers to avoid damaging fish plates under overload conditions, partial short through a derailment etc

 

I believe you have stated in the past that you do not use DCC, so please stop spreading this mis-information and FUD about DCC.

 

Your figure of 4 Amps is a completely arbitrary figure plucked out of the air, and wrong for most systems.

 

DCC does not damage fishplates or point blades. If the layout is wired correctly the cutout will operate almost instantaneously and prevent any damage. If the layout is not wired correctly (e.g. relying on fishplates to route power to the layout) then the cutout will not work correctly in the event of a fault, but the fishplates will be the last thing to suffer damage.

 

Andrew

[Redford73]

I have avoided so called cab control and sections in the past as my layouts simply haven't needed them.  I use isolating sections in yards which obviously have separate feeds and switches but the main layouts I've had so far ran fine with the one feed to each main line and I used points to isolate sections where necessary.

 

Do I really want to complicate things by adding droppers every yard or so?  

 

I'll be using multicore 16/0.2mm wire from controllers to track so unless I'm at risk of losing power on the layout somewhere I don't really see the need.  Just wondered whether extra droppers would improve/watertight electrical conductivity.

 

And I wont be using DCC.  I always state that I am DC in the threads I start but often find I get advice on DCC.  

[CourthsVeil]

Extra droppers surely would improve conductivity and – to answer your question in the OP – splitting the feeds from the outputs would be a benefit.

But, taking into account the dimensions of the layout and of the wire used, there is no need to add droppers "every yard or so".

 

Regards

   Armin

 

 

PS: in this respect DC is much easier to install/use than its modern "successor"

            (to avoid the ugly  3-letter-abbreviation   here ).        

[kevinlms]

How are your different sections of track joined electrically? Just fishplates, or droppers soldered and wired past the joints? Because think about why you would need extra feeds. If using just fishplates then other feeds would be good, but they need to be fairly heavy cable, or you'll have volt drops on a long run.

The OP has a layout 12' by 8', so doesn't have any 'long runs'.

 

IMO as long as not relying on rail joiners (their function is to join & align the rails physically) to reliably carry the voltage, then almost any size wire will be adequate for that size layout. Rail joiners may appear to work quite well, but when a layout gets older & has been ballasted & glued, then the resistance can become higher, thus causing voltage drop and therefore the trains to become slower - probably in some sections.

 

If someone builds layouts and turns them over quickly, its probably not worth the trouble of extra wiring. But if the owner plans to keep the layout for several years (some people take on a lifetime project), then its definitely worthwhile. So no one answer fits all.

[kevinlms]

Extra droppers surely would improve conductivity and – to answer your question in the OP – splitting the feeds from the outputs would be a benefit.

But, taking into account the dimensions of the layout and of the wire used, there is no need to add droppers "every yard or so".

 

Regards

   Armin

 

 

PS: in this respect DC is much easier to install/use than its modern "successor"

            (to avoid the ugly  3-letter-abbreviation   here ).        

But what is good wiring practice applies equally, whether DC or DCC (avoiding using those 3 letters, doesn't change the argument).

[CourthsVeil]

Kevin,

I didn't claim it's better practice, I just said it's easier to manage…

 

We shouldn't take a little joking (ugly 3 letters) too serious, should we?

 

   Armin

[kevinlms]

Kevin,

I didn't claim it's better practice, I just said it's easier to manage…

 

We shouldn't take a little joking (ugly 3 letters) too serious, should we?

 

   Armin

Maybe, it depends on the complexity of the layout. While 12' by 8' layout, isn't huge, you could fit a fair amount of track on it.

[14Steve14]

Before DCC came along, as far as I am aware no one ever used the term dropper wires. There was no need for a bus wire of any size as the track carried the current. I have looked through many older electrical wiring books for model railways and cannot find the term anywhere. DCC has come along and people are getting confused between the electrical wiring differences between the two different types - DCC and DC analogue.

 

Depending on the complexity of your analogue layout and the types of points used, you may have to add power feeds to bits of track, such as sidings that go against the feed of the points. Remember that the power should always be applier to the toe of the point.. Where an additional power feed is added you should use insulated rail joiners to prevent shorts. If you want to sectionalise the layout or even a siding make sure you use insulated fishplates or no fishplates.

 

In an ideal world when using analogue you should really use different controllers for different areas of the layout, so an up line will need a different controller to the down line. Fiddle yards and other areas can have their own controller also, so remember to keep each area electrically separate, through insulated fishplates or switches.

 

Glad to see someone not using DCC.

[Silver Sidelines]

I do believe that SECTIONS have been around on model railways for a long time.  My Bible was the Reverend Beal's book  - West Midland - which dates from the 1950s.  There are three pages here which deal with DC wiring. 

 

https://flic.kr/p/bJiT4X

 

https://flic.kr/p/bvp7EU

 

https://flic.kr/p/bvp7gA

 

He used batteries for his DC supply but otherwise it is all very recognisable as CAB CONTROL.  As to terminology - well just humour people.  The principle of using a COMMON RETURN has been around at least as long as Railway Modeller and CJ Freezer's track plans which were annotated to show all the TRACK FEEDS.

 

Regards

 

Ray

[Talltim]

Personally I would put in more than one feed/dropper per section simply to provide some redundancy.

[Steven B]

Before DCC came along, as far as I am aware no one ever used the term dropper wires. There was no need for a bus wire of any size as the track carried the current. I have looked through many older electrical wiring books for model railways and cannot find the term anywhere. DCC has come  along and people are getting confused between the electrical wiring differences between the two different types - DCC and DC analogue.

 

Where has this misconception come from? There is no difference to the wiring of a DC layout and that of a DCC layout (other than the lack of section switches on the latter). What works with one will work with another. In both cases you're connecting the track to the output of a controller. Trains will still run if the wiring's done with miles of 7/0.2 and section switches or a few feet of 16/0.2 and shorter dropper wires. All that's different is the electrical characteristics of the wiring (i.e. resistance/Voltage drops). What works well for one will work well for the other.

 

If you're happy taking one pair of wires to a circle of train and relying on fish-plate/track-joiners to carry the power then you can do so in DC or DCC. Reliability of either control system can be improved by fitting more track feeds for the simple reason that copper wire conducts better than nickel-sliver rails. For example, my dad's DC layout worked much better once a second set of track feeds was added to the far side of a large loop.

 

 

 

Happy modelling.

 

Steven B.

[mcowgill]

Additional power feeds/droppers, call them what you will, are 'best practice' but not necessary.

 

All the layouts I have built since a teenager in the late 70s (DC and later DCC, 009, N, 00, EM & P4) have been wired in exactly the same way apart from no section switches on DCC - with one exception which was a quickie using rail joiners.  Never again, creeping electrical problems grew over time, particularly after ballasting and lots of PVA glue, so it turned out to be a false economy.

 

Incidentally I've just converted a 009 layout back from DCC to DC - 'just add switches'!

 

Martin

[Chimer]

Where has this misconception come from? There is no difference to the wiring of a DC layout and that of a DCC layout (other than the lack of section switches on the latter). What works with one will work with another. In both cases you're connecting the track to the output of a controller. Trains will still run if the wiring's done with miles of 7/0.2 and section switches or a few feet of 16/0.2 and shorter dropper wires. All that's different is the electrical characteristics of the wiring (i.e. resistance/Voltage drops). What works well for one will work well for the other.

 

If you're happy taking one pair of wires to a circle of train and relying on fish-plate/track-joiners to carry the power then you can do so in DC or DCC. Reliability of either control system can be improved by fitting more track feeds for the simple reason that copper wire conducts better than nickel-sliver rails. For example, my dad's DC layout worked much better once a second set of track feeds was added to the far side of a large loop.

 

 

 

Happy modelling.

 

Steven B.

 

Exactly right.  But of course with DCC you need the extra feeds to all the sidings and loops that would otherwise be isolated by points being set against them if you want all the lights, bells, whistles and other noises of DCC to keep working on stock parked in said sidings and loops.  If you provide the same extra feeds with DC, you need switches in the circuits to enable you to leave locos in the sidings at all (in addition to the ones you need if you want to park more than one in the same siding) as you are over-riding the automatic isolation provided by the points

 

The OP has a layout 12' by 8', so doesn't have any 'long runs'.

 

IMO as long as not relying on rail joiners (their function is to join & align the rails physically) to reliably carry the voltage, then almost any size wire will be adequate for that size layout. Rail joiners may appear to work quite well, but when a layout gets older & has been ballasted & glued, then the resistance can become higher, thus causing voltage drop and therefore the trains to become slower - probably in some sections.

 

If someone builds layouts and turns them over quickly, its probably not worth the trouble of extra wiring. But if the owner plans to keep the layout for several years (some people take on a lifetime project), then its definitely worthwhile. So no one answer fits all.

 

One of their functions, sure.  But since the first electric train sets appeared, fishplates have also had the job of providing electrical continuity, and usually succeed in doing so.  Provide some extra feeds for redundancy, sure.  But the oft-recommended feed to every piece of track seems overkill to me (ducks for cover ...) 

[Richard Lee]

If you provide the same extra feeds with DC, you need switches in the circuits to enable you to leave locos in the sidings at all (in addition to the ones you need if you want to park more than one in the same siding) as you are over-riding the automatic isolation provided by the points

Alternatively, with DC, you can connect the rail coming from the frog to the frog (or the switch controlling its polarity), assuming that you are using electrofrog points.  Not only does that make the layout easier to operate (less switches to turn on and off) but I find that it reduces the number of points that I try to go over when they are set the wrong way.

[Redford73]

I didn't realise this query would generate so much controversy particularly in that I am running a DC layout and made no reference to DCC.

 

I think what I can take from the above is that I will start with my usual method of one feed per main circuit and if it doesn't power the layout adequately add one or maybe two extra feeds to each of the three circuits but otherwise if it aint broke ... I never had any problems with one feed to each line and rail joiners used to conduct power.  I know how to isolate sidings and sections with points or insulating joiners and have already accounted for this at the planning stage.

 

Ignoring DCC which has no relevance in my case as I don't use it and don't intend to (too many locos to fit if you're wondering) it's really a question of whether the extra wiring if I start adding feeds is going to be outweighed by the benefits of better running.  

[kevinlms]

 

Ignoring DCC which has no relevance in my case as I don't use it and don't intend to (too many locos to fit if you're wondering) it's really a question of whether the extra wiring if I start adding feeds is going to be outweighed by the benefits of better running.  

Yeah, I don't understand why DCC keeps getting mentioned, given the title of the sub header. People should read before they answer.

 

I do believe that you've been given some pointers as to why extra droppers are beneficial. Whether its worth the effort, is entirely up to you. You could add them later if you find the running is unreliable, but it can be harder to do later - its hard to solder wires to painted rails, than it is nice clean ones, for instance.  But its your choice and some will say 'I told you so'.

[Crosland]

Good layout wiring techniques such as appropriate wire sizes (determined by length and expected current), multiple feeds, isolating and switching frogs, etc., apply equally to DC and DCC. There are no real DC only or "DCC friendly" techniques.

[kevinlms]

Good layout wiring techniques such as appropriate wire sizes (determined by length and expected current), multiple feeds, isolating and switching frogs, etc., apply equally to DC and DCC. There are no real DC only or "DCC friendly" techniques.

Well yes, but isn't that exactly what I said in post 9?