Dcc wiring help - reliability

[Jonnyb]

No doubt you more than experienced people (basically everyone) can help me as I’m having some trouble with my Dcc layout build.

 

it’s about 9ft by 10ft square with a double circuit but with a single line section. It has a series of point and I have so far laid the track and wired in two thirds and been testing as I go. 

 

I have the gaugemaster prodigy system  and have a few problems.

 

1. The trains run better / quicker over some sections/pieces of track than others

 

2. I have Dcc concepts point motors, is it best to remove the point springs?(Peco oo code 75 and some bullhead)

 

3. I have live frogs but small locos still stall, is there a way to resolve this?

 

4. some the engines are very slow to react. The worst is my Hornby 2800 class, you need to wind the controller up quite a lot before it will move. Hornby decoder in that one

 

5. my point motors use gaugemaster push to make contact switches but sometimes it take a couple of attempts for them to work

 

I used mains Light grade (twin and earth) cable for my bus wire with 0.8 mm droppers on all pieces of track. And the same grade wire for the point motors
 

I was wondering if the size of the layout was too much for the controller of if I should have used different gauge wire.

 

it’s almost like their isn’t enough current or too much resistance 

 

I also run the points directly off the bus wire, I’m now thinking that I should have run one power feed from the bus wire on each board to a distribution block and all the smaller wires from that.

 

maybe the whole thing needs a rewire but as other people will have experienced, an unreliable layout is an unused layout…sorry for the essay

 

 

[Robert Stokes]

I can only answer some of the points you have raised. Firstly I think that with a layout of that size it would have been better to use mains cable for sockets, not lighting cable. Voltage drop may explain the slow running.

 

You mention using DCC Concepts point motors. Are these the slow-action type? If so then you definitely should remove the springs and should use DPDT switches which give constant current instead of push buttons.

 

Have you adapted the points to feed power to the frog by a switch on the point motor rather than rely on blade contact?

 

I don't know anything about the Prodigy so can't comment on that.

[Jonnyb]

9 minutes ago, Robert Stokes said:

I can only answer some of the points you have raised. Firstly I think that with a layout of that size it would have been better to use mains cable for sockets, not lighting cable. Voltage drop may explain the slow running.

 

You mention using DCC Concepts point motors. Are these the slow-action type? If so then you definitely should remove the springs and should use DPDT switches which give constant current instead of push buttons.

 

Have you adapted the points to feed power to the frog by a switch on the point motor rather than rely on blade contact?

 

I don't know anything about the Prodigy so can't comment on that.

Hi thanks for helping with this, I do have the slow acting motors so I will remove the springs then.

 

I haven’t come across dpdt switches before so I’ll give them a look too and I do have the frog switching off the point  motor, most are fine but one or two aren’t great.

 

maybe power cable will be better, might be worth putting a voltage reader on each piece of track and see the results

[Robert Stokes]

Yes use a voltmeter, but it will have to be one that works with AC and up to at least 15V. My NCE Power cab delivers 13.8V at the track. It should read virtually the same figure all round if the bus wire is thick enough.

[RobinofLoxley]

Track laying looks good, could it do with a clean. Opinions vary but I would run a track rubber over the slow sections.

 

For a small layout the selected cable should be OK.

 

Are the points converted the recommended way with jumpers or do you rely on existing electrical contacts?

 

Point motor have to get their power somewhere, if you suspect you are short of power you could get a separate 12v supply for them, but running 2 locos max (no sound?) you should have power available. Its right about the switches, if you have stall motors you need a continuous power supply not a pulse

 

For individual locos running badly you have to question the setup of the decoder

[Robert Stokes]

You might like to try a variable DC voltage source for the point motors. I'm thinking of the plug-in type which give out 3, 4.5, 6, 7.5 and 9V. I have found that using 9V (or possibly even 7.5V) makes the points change more slowly and more quietly - which I think is better. Remember, that sort of point motor needs very little amperage. A 1A source is more than enough.

[mikeg]

The Prodigy is more than capable, I have used one on a 40x20ft O gauge layout running 4 locos, the track voltage should be 18/19v as standard. I think that the problem is the use of lighting cable, I used this for the connecting wire from the bus wires and had to replace most of the long runs I used solid mains cable. The points as Robert has said are best supplied with a reduced voltage, I have used 9v and they are more reliable. I was advised by DCC Consepts to use a resistance when using the main DCC bus as the supply.

 I think that your track might be affected by damp air from the scenery as it looks very dull, I use the end grain of a piece of 50*25 softwood about 50mm long to clean my track as it doesn’t scratch the top of the rails.

 

regards mike 

[ITG]

I use the GM Prodigy Advance2, and as a relative newcomer, haven’t experienced that array of unreliability. There seems to be several potential causes:

1. As others have said, have you modified live frog points? How? Is frog power switched?

2. variable speed on plain track sounds like poor conductivity, either due to dirty track or inconsistent track feed maybe

3. loco start and acceleration maybe due to decoder CV settings.

 

I think it may be prudent to try to deal with one symptom at a time.

[kevinlms]

46 minutes ago, Jonnyb said:

maybe power cable will be better,

You can double up on your lighting cable, if you have an existing stock to use up.

[WIMorrison]

2 hours ago, Jonnyb said:

 

2. I have Dcc concepts point motors, is it best to remove the point springs?(Peco oo code 75 and some bullhead)

 

 

Which type of DCC Concepts point motor, they make at least 3 different motors and how you use them to wire up is different.

[Jonnyb]

I have cleaned the track that was an old photo but it does sound like an upgrade to the bus wire would be sensible if it doesn’t improve.

 

For the points I just removed the jumpers from underneath as per Peco instructions and use the think wire as the switchable frog. Like I say some are okay but they don’t all work as well as each other.

 

It does sound like some the decoders haven’t been set up well, tbh I have no idea how I would go about changing that.

 

But like you say, sensible to tick one thing off at a time 

[Jonnyb]

50 minutes ago, WIMorrison said:

 

Which type of DCC Concepts point motor, they make at least 3 different motors and how you use them to wire up is different.

I have the cobalt ip digital ones

[WIMorrison]

Assuming you are powering these motors from the same power as the track, you can use the S1-Frog output to feed the frog, which should help any stalling as locos go over the blades and frog. You can find the details of how to wire it up correctly on the DCC Concepts or Peco website.

 

You don't need to worry about voltage as these are designed to run from the track power, also you don't need any DPDT switches as the motor has one built in - hence why I asked about the type of motor

[DCCconcepts]

5 hours ago, Robert Stokes said:

 

 

You mention using DCC Concepts point motors. Are these the slow-action type? If so then you definitely should remove the springs and should use DPDT switches which give constant current instead of push buttons.

 

 

 

2 hours ago, Jonnyb said:

I have the cobalt ip digital ones

 

As the OP is using Digital IP motors they do not need DPDT switches.

The "PBS" manual switch terminals on a Digital IP must have a short break before make contact. So on/on type SPDT switches aren't suitable. On/off/on maintained contact switches can be used but don't flick them directly from on to on - it needs the slightest of pauses in the middle off position.

Ideally a pair of momentary pushbuttons connected 7-8 and 8-9  or a spring return to centre on/off/on toggle switch SPDT type is the best choice.

Or they can be operated from the DCC system (see below regarding the Prodigy)

 

Yes - we recommend removing the over centre springs when using slow action motors - regardless of manufacturer.

 

4 hours ago, mikeg said:

The points as Robert has said are best supplied with a reduced voltage, I have used 9v and they are more reliable. I was advised by DCC Consepts to use a resistance when using the main DCC bus as the supply.

 

 

The resistor (typically 270-330 ohm) was recommended for use with the original Digital (and analog) motors produced pre-2014. The later Digital IP motors are quite happy with a wider DCC voltage input.

 

2 hours ago, WIMorrison said:

Assuming you are powering these motors from the same power as the track, you can use the S1-Frog output to feed the frog, which should help any stalling as locos go over the blades and frog. You can find the details of how to wire it up correctly on the DCC Concepts or Peco website.

 

You don't need to worry about voltage as these are designed to run from the track power, also you don't need any DPDT switches as the motor has one built in - hence why I asked about the type of motor

 

If the OP is using the basic Prodigy system then it is not capable of controlling accessories - so will require control of the motors via the manual PBS terminals.

 

The internal switch S1 switches the DCC IN feed back out to the FROG terminal, so is ideal for connection of an electrofrog when using a common DCC bus to feed track and point motors.

But if using a separate accessory feed then the track/frog will need switching via the S2 switch and the S2-L/C/R terminals.

 

Best Regards

The DCCconcepts Team

[Michael Hodgson]

If the trains are erratic on some parts of the track I am wondering whether you have long runs of track powered by insufficiently frequent feeds, and losing power by resistance/unreliable connections between fishplates?  Some people advocate a separate dropper from the bus to every length of rail. 

[Harlequin]

Hi Jonny,

How are your droppers connected to your bus wires?

 

[Ron Ron Ron]

17 hours ago, Jonnyb said:

......it’s about 9ft by 10ft square with a double circuit but with a single line section. .....

........I have so far laid the track and wired in two thirds and been testing as I go. 

 

 

I assume that 9 x 10 is around the outside of a room or space, with operating from inside

That's 38ft in length  .....multiplied by the amount of track.

What is the topology (layout) of your DCC track power bus?

Is it fed from one end, or at a mid-point?

Is it a single bus, or is there more than one?

 

 

17 hours ago, Jonnyb said:

...... have the gaugemaster prodigy system  and have a few problems....

 

......I was wondering if the size of the layout was too much for the controller of if I should have used different gauge wire.

 

it’s almost like their isn’t enough current or too much resistance 

 

 

Which Prodigy system....  Prodigy Advanced (3.5 amps)   or Prodigy Express (1.6 amps) ?

 

 

 

.

[Sir TophamHatt]

21 hours ago, RobinofLoxley said:

Opinions vary but I would run a track rubber over the slow sections.

I wouldn't.
But as the OP says, opinions differ on this.

[SamThomas]

I would check the voltages round the trackwork using a meter with a load (such as a 12v vehicle indicator bulb/lamp/globe) connected in parellel with it (the load will help to highlight any loose/dry/defective connections.

 

Also, I would invest in a couple of rolls of single flexible cable for the bus - cost less than the price of a couple of mid range decoders.

 

 

[Oldddudders]

On 24/09/2021 at 02:16, Michael Hodgson said:

Some people advocate a separate dropper from the bus to every length of rail. 

Money in the reliability bank. Tedious but rewarding. But just as there are debates about using abrasives on the railhead, so there are about how to join droppers to the bus. I am firmly in the suitcase connector lobby. Others prefer to solder both ends of the dropper,  requiring removal of insulation on the bus, which is less than fun working underneath the baseboard.

 

Hint : never solder under the baseboard while wearing shorts....

[Robert Stokes]

 

2 hours ago, Oldddudders said:

Others prefer to solder both ends of the dropper,  requiring removal of insulation on the bus, which is less than fun working underneath the baseboard.

 

Which is why on my latest layout I have arranged for the bus wires to run along the front of it. They are stapled to the 70mm wide main frame between two pieces of 11 x 6 mm strip wood. This makes working on it much easier. When all wiring is complete, this is covered by a painted piece of hardboard pinned to the two strip wood pieces. This makes a nice facia.

Edited September 26, 2021 by Robert Stokes
removing duplicated word

[KingEdwardII]

2 hours ago, Oldddudders said:

never solder under the baseboard while wearing shorts....

Hmm, my rule is simply "never solder under the baseboard" - period.

 

If you think about soldering under there - think again. There will be a better way.

 

"Suitcase" connectors - more formally called Tap Splice connectors - are also my approach for connecting to the bus wires. Simple and speedy. No danger to life or limb.

 

Yours,  Mike

[WIMorrison]

3 minutes ago, KingEdwardII said:

…

 

"Suitcase" connectors - more formally called Tap Splice connectors - are also my approach for connecting to the bus wires. Simple and speedy. No danger to life or limb.

…

they are actually called Insulation Displacement Connectors (IDC).

[KingEdwardII]

7 minutes ago, WIMorrison said:

they are actually called Insulation Displacement Connectors

You're right, although that name is really for the technology involved, which applies to a wide range of connector styles, including some for ribbon cables.

 

However, using that term won't help you very much to find a supplier of the "suitcase" style connectors most useful with bus wires - "Tap Splice Connector" or "Quick Splice Connector" seem to be the terms used by RS-Components and the like, with "ScotchLok" also being used, derived from the name of the 3M product of this kind.

 

One thing that's good about them is that they are really cheap - a few pence each. So no problem if you have loads of connections to make.

 

Yours, Mike.

[Crosland]

21 hours ago, KingEdwardII said:

One thing that's good about them is that they are really cheap - a few pence each. So no problem if you have loads of connections to make.

 

 

Do make sure you use the correct size (colour) for your cable. They tend to have a bad reputation in some circles, but that's entirely due to poor application, rather than any inherent issue.