DC and DCC Powered Layouts

[Jonathan.M]

Hello,

 

I’ve seen a few articles in Hornby Magazine saying that people’s layouts are powered by both DC and DCC control. How would this be possible?

 

Jonathan.M

[SRman]

In my case, I have wired the lower level tracks only to be switchable between DCC and DC. This could have been achieved simply by using a Double Pole Double Throw (DPDT) switch - I actually used two initially but this carried a risk of switching one track to DC and leaving the other on DCC which required some self-discipline to never switch one without the other. However, there was a complication: The  setup is double-tracked and I wanted to control the whole lower level from the one DCC system (NCE Power Pro) but from two separate analogue controllers (an old H&M Duette). 

I used a multi-layered multi-pole rotary switch to achieve this. It took me quite a while to work out the wiring to feed both tracks from the DCC system yet feed each track from a different control knob on the H&M unit. I tested it all carefully using a separate NCE Power Cab before trying any trains on it, just to make sure I didn't fry my expensive 5 amp system.

The rotary switch positions also allow me to disconnect the tracks completely. Additionally, with the view to running older analogue stock, I wired some isolating switches into the passing loops and siding--branch line. These are left on for DCC running, but switched off for DC running, meaning I can run one or two DC locomotives while leaving other trains (DC or DCC) on the tracks.

The upper level of my layout is wired purely for DCC and has no connection at all to the lower level.


Control Panel Update 10-08-15 by Jeffrey Lynn, on Flickr


Control Panel Update Underneath the Panel 10-08-15 by Jeffrey Lynn, on Flickr

Edited April 19, 2019 by SRman

[Phil S]

IF the original layout started out as a 'trainset oval' or similar, and made use of the COMMERCIALLY PROVIDED power feeders ....which will have included interference suppression capacitors across the rails.... Then THESE capacitors MUST be removed before the layout an be used for DCC ( which is an ac signal ).

((You may find the description of DCC as a 'dc-coupled ac waveform' helpful, as the the frequency response extends to 0 hertz (DC). But it is undeniably an ac waveform, however lenz decoders with USP will work through a sheet of paper ...ie without the 0Hz/DC connection.))

 

With 'home made' power feeds ...... There are unlikely to be ANY such capacitors installed .... I know I've never fitted one on a track feed.

 

Then, on the basis that 'existing wiring' from the analogue layout is being  used for the DCC distribution when in that mode, the user should ensure that it will carry the current needed to trip the short circuit protection level of their DCC controller .... If this is only a 1-2Amp DCC controller it will probably suffice, but if it has a typical 3-5A or higher rating, this increasingly unlikely. ...so the 'solution' is to use lower-setting circuit breaker(s) such as the PSX ( NCE also did one .... But as I recall it only worked up to 16V ). ( the psx can be set to currents from about 1.25A up) .... Then the PSX will protect the track beyond it. ( in the same way as your 230Vac consumer unit/circuit breaker/fuse board protects lighting and other circuits with 5A, 15A, 30A breakers from the 70-100A incoming supply )

 

A layout intended for 'one engine in steam' expects little current difference between analogue and digital running, whilst a layout with multiple tracks such that many locos are likely to be running at the same time, in the same electrical section, would have an expectation of wiring for continuous higher currents ... And a distinction should be made between the different types of layouts

[Ron Ron Ron]

4 hours ago, Jonathan.M said:

Hello,

 

I’ve seen a few articles in Hornby Magazine saying that people’s layouts are powered by both DC and DCC control. How would this be possible?

 

Jonathan.M

 

In most cases this will probably mean that the layout is wired for use with either DC or DCC, rather than both at the same time.

i.e. only DC or only DCC.

 

This would be achieved by simply only connecting one type of system at a time (e.g. unplugging one and plugging in the other), .....or by a secure and safe way of switching between the two.

 

 

[Nigelcliffe]

Agree with Ron.   With Coldfair Green, we were wired for both, but only one at a time.  The layout was originally DC, so initially going DCC just meant changing the controller attached to the main input feed.   Later on, we added more electronics (push button control panel for turnouts, signals, uncouplers and level crossing driven by LocoNet) though the changing of track power remained a single large rotary switch to "DC" or "Track-Off" or "DCC".   

 

 

 

[Jonathan.M]

SRman and Phil S,

 

Thank you for helping, but I’m not very good at complex wiring, let alone understanding it. If I knew what you were talking about, I’d take your advice! Thanks for trying to help.

 

Jonathan.M

[Corbs]

20 minutes ago, Jonathan.M said:

SRman and Phil S,

 

Thank you for helping, but I’m not very good at complex wiring, let alone understanding it. If I knew what you were talking about, I’d take your advice! Thanks for trying to help.

 

Jonathan.M

It’s not complex. The controller supplies the power to the track at multiple points on most layouts.

 

 But the power output from the back of the controller is just two wires that get split up to go to multiple places.

 

All you are doing is changing these two track power feed wires to come from either the DC controller or the DCC controller. Whether you do it with a switch as described above, or by literally unplugging the wires from one controller and into another, the result is the same. 

The main thing is to NEVER allow both controllers to be supplying power to the track at the same time.

 

[Jonathan.M]

Corbs,

 

Thanks for clarifying. I don’t really understand ‘Double pole double throw’ or anything like that.

[Ron Ron Ron]

4 hours ago, Jonathan.M said:

......I don’t really understand ‘Double pole double throw’ or anything like that.

 

Just don’t mix DC and DCC power and control on the same layout.

 

 

Don’t put a non-DCC fitted loco (DC) on a DCC powered layout.

 

 

A DCC decoder fitted loco can normally be used on a DC powered layout, with some provisos.

e.g. 

Decoders don’t like certain types of DC controllers (e.g. feedback type) and may run erratically.

DC (so called) electronic track cleaners,  such as Relco and Gaugemaster types, will destroy DCC decoders. Avoid at all costs!

DC running must be enabled in the decoder’s settings (CV’s).

 

Keep it simple.

[Corbs]

4 hours ago, Jonathan.M said:

Corbs,

 

Thanks for clarifying. I don’t really understand ‘Double pole double throw’ or anything like that.

 

Maybe this link will aid you in your quest?

https://learn.sparkfun.com/tutorials/switch-basics/all

[Michael Edge]

Herculaneum Dock uses DC for the BR (CLC) part and DCC for the Mersey Docks system, taking advantage of the operation not involving any locomotive movements between the two. In three places around the layout wagons are pushed up to or through the dock gates, a section of track is completely dead to both systems at these points. The overhead railway is also DCC but that is completely separate. Incidentally the dock system wasn't rewired for DCC, we just use it with all the section switches on.

[Jonathan.M]

Thanks for everyones help.

 

Jonathan.M