DCC for G Scale Trams

[DafyddElvy]

Please bear with me on this, I'm not sure what the question is that I want to ask, so I'll try and give an idea of where I am and what I think I want.

I am perfectly familiar with DCC, I have already built 2 0 gauge layouts most DCC controlled and I am coming close to the end of a fully DCC controlled 0 gauge layout, just don't quiz me on CV's.
I am a firm believer and committed from a hardware side to using Digitrax, with no intentions of wanting to move to a new system.

I am in the process of building an indoor 1:22.5 (avoiding the reference to G as a scale) scale layout, layout design is still being finalised, but all is sufficiently advanced that baseboard assembly starts this weekend.

I will when I get around to finishing it, also gave a garden line which is being built specifically with running trams and live steam in mind. All my trams presently have 12v motors fitted because when this large scale journey started my models would either be battery or live steam powered.

That's basically where I am, the only variable has been the decision to build a large scale tramway themed layout.

So, to run DCC outdoors my thinking is to run a 2.5mm multi core BUS the length of the line and put droppers from the BUS to each individual rail, as I do with my layouts.

My Digitrax system has a setting for G Scale/LGB, I don't really want or need to fit big decoders to trams with 12v motors, but could I be setting myself up for problems if I use 0 scale decoders, if someone visited with a model that was fitted with sat and LGB compatible decoder will it work with an 0 gauge DCC track voltage, I am guessing that if I put a model with an 0 gauge decoder on a track putting out an LGB DCC voltage the decoder isn't going to be very happy and is likely to burn out, not running my models on others track is perfectly acceptable??????

If you have read this far thank you, some advice and suggestions would be appreciated please, thanks.


David

 

[PhilP]

Hi David,
As long as there is enough voltage to wake the electronics up (5-6V) is usually enough, then your track voltage will limit the maximum speed of anything visiting your line with a bigger capacity decoder.

I would be more concerned about current limits of you Digitrax setup.
Using 'lies to children' analogies, if a visiting loco draws 1A at 24V, then to generate the same amount of power at 12V, it will require 2A.
Depending on what else is running, you may be getting close to the limit for the Digitrax CS you have?
From memory, the unit I have is rated 2.5A.

Also, from memory, if you set Digitrax to 0 gauge voltage, you are putting out 19V as track voltage.

DCC, and overhead power, are not good bed-fellows.
By all means try a section, but try it before committing to running this way, especially once you get outside.

YMMV, of course.

PhilP.

 

[Software Tools]

DCC, and overhead power, are not good bed-fellows.

Onboard power buffers eliminate the few problems with a single point of power pickup. The Southern California Traction Club runs DCC with overhead power very successfully.

 

[DafyddElvy]

The replies are exactly why I posted here, a world of knowledge and people who will pose the concerns and otherwise I need to consider.

The Digitrax system I am using is an 8amp one, I'm not up to speed with Digitrax's latest models, but at the time this was the heaviest, in power terms, system available, the out put track voltage is circa 15volts, which once its been through the decoder gives the motor a max 11v ish.
A slight digression, for some reason known only to heljan, the power draw of their 0 gauge models requires a minimum 5amp track feed, but that's a topic for someone else to worry about.

So I think I'm going to be okay on the power side.

On both outdoor and indoor set ups the DCC track BUS is only be used for track power, any accessories are powered from a separate power BUS and I make full use of the Loconet on my indoor layouts. Its the track BUS and track voltage plus decoders that I am asking/querying here.

What else am I not seeing that I should be considering, I've destroyed enough decoders in my short, relatively speaking, time using DCC and I'd rather avoid the costly mistakes again.

I am going to type this and I'm cringing at the thought of what some of the thread deviators and comedians are going to reply, but I welcome peoples thoughts about my venturing in to using DCC in the larger scale, thanks.


David

 

[Brixham]

I wouldn’t fit smaller scale decoders to anything G scale.
Fine whilst running on your lower voltage track, but what happens if it’s run away from home? Even on a high voltage analogue line.
I know fitting large scale decoders comes at a higher cost than smaller scale one.
LGB motors are quite efficient, some other brands less so. A single motor shouldn’t draw much more than an amp.
With trams, high speeds are not required, so a lower track voltage makes more sense.
Malcolm

 

[Rhinochugger]

I still have to question the need for a BUS. The cross-section size of even code 200 track is going to be bigger than any BUS cable. The weakness, as we all know is the LGB slide-on fishplate. Use track clamps or the Bachmann (ex Aristocraft) screwed fishplates if you can put up with drilling and threading the fiddly size and save a huge amount of cost and effort.

I get at least 75ft without noticeable voltage drop - some of my track lengths are LGB flexi, so1200mm, but otherwise I have the usual 900mm and 300 mm lengths.

 

[Brixham]

Several years ago, a fellow GSS member laid his track around 200 ft in an oval with only ONE power feed. Over the intervening years, the connectivity became poor, with several dead spots.
Before getting the layout running after the big nasty flu, we ran a bus wire using twin and earth, with drop points to the track every 10 feet or so.
After 3 years, track power is still good.
On initial track laying, LGB conductive paste was used in all joints which helped for several years before 2020
Malcolm

 

[Rhinochugger]

Several years ago, a fellow GSS member laid his track around 200 ft in an oval with only ONE power feed. Over the intervening years, the connectivity became poor, with several dead spots.
Before getting the layout running after the big nasty flu, we ran a bus wire using twin and earth, with drop points to the track every 10 feet or so.
After 3 years, track power is still good.
On initial track laying, LGB conductive paste was used in all joints which helped for several years before 2020
Malcolm

OK, let's re-set.

When LGB introduced K scale, later to become G scale, if you look at the adverts, it wasn't intended for permanent outdoor track laying. Slide-on fish plates were simply a 'bigging up' of the practice in smaller scales. (It frustrates me that they have steadfastly refused to review their methods - just like R3 points.)

Conductive paste is a sticking plaster - very temporary.

There are, however, good permanent solutions both with track clamps and screwed fish-plates. My track has been down for ten years in this location, six years at the the previous one, and I have not yet suffered a significant reduction in connectivity.

I have two feeds to roughly 300ft of track, the second feed bisecting the circuit. So, the current only has to flow 75 ft before it meets itself coming the other way round. That said, the cable that runs across the approx diameter of the circuit is over ten feet, about four or five rail joints, away from the incoming feed - lack of planning and forethought

I've had the odd loose connection in ten years, and I also found one or two fishplates where I'd forgotten to actually put a screw in but my track powered trains have always kept running, and with a lengthy clean using the Mk 1 LGB track cleaner (300 ft takes a while by hand ) I ran track power a couple of weekends ago - I think this will be the tenth season.

 

[dunnyrail]

My experiences with track power were much similar to Rhino’s. For my happy-state I split my layout into 6 or 7 sections with a bus feeding each end of the isolated section. I have mentioned this in the past being ridiculed by some but it worked for me and the only reason I went dead rail was the hassle of cleaning some 300 feet of track for reliable slow running and shunting during my Timetable sessions. Much of the wire is still present but the switchable panel and a lot of wire has now been removed, my line is fully clamped with Hillman and Massoth Clamps, these have been left in place as they help to keep track nicely in place.

 

[JimmyB]

my line is fully clamped with Hillman and Massoth Clamps, these have been left in place as they help to keep track nicely in place.

I am both live steam and battery, and I find clamps, and or Aristocraft screwed fishplates vital to stop track sliding apart.

 

[Paul M]

When LGB introduced K scale, later to become G scale, if you look at the adverts, it wasn't intended for permanent outdoor track laying

Let's face it, LGB stuff is great. It does exactly what it says on the box!
OK so the fishplates my not be the best method of contact, but even so they work extremely well for what they're designed for, even in the differing climates of world wide gardens

 

[dunnyrail]

Let's face it, LGB stuff is great. It does exactly what it says on the box!
OK so the fishplates my not be the best method of contact, but even so they work extremely well for what they're designed for, even in the differing climates of world wide gardens

Before I got into coamps whilst still on track power I used to pull power failed joints apart, squeeze tight all rails in situ and push back together again. Worked every time, only just remembered this fix….it was a long time ago!

 

[Rhinochugger]

Let's face it, LGB stuff is great. It does exactly what it says on the box!
OK so the fishplates my not be the best method of contact, but even so they work extremely well for what they're designed for, even in the differing climates of world wide gardens

Yep, I think the thing is that because the LGB stuff is for the greatest part extremely good, it's just frustrating that the one or two minor niggles never got revisited and ironed out.

As I said, the pictures that I've seen promoting K scale, showed the original Stainz set on a simple layout going out of the french doors, onto a patio, and back indoors, so it's easy to understand why sliding fishplates were considered good for the job, especially as it was clearly envisaged that the track would be taken apart at the end of the day.

However, that was 1968 ........................

 

[Dan]

I have the Zimo DCC system and it has a 8 amp and a 12 amp output. Both are adjustable for 12 to 24 volts as well as the current output is adjustable. Also the Zimo MX45 decoder is for any scale as it is a 24 volt HO decoder and handles 1.2 amps and can control servos, lights, smoke, sound (3 amp speakers) etc. Zimo has also made a better version of the MX645 and has 16 bit audio instead of 8 bit.

 

[Bill Bagal]

Original poster refers to a 2.5mm bus with droppers to each piece of track, and another poster questions the merits of this. Went through this exercise recently and came to the conclusion it would be better to invest in rail clamps than a bus wire. I'm not sure of the cross section area of LGB 332 but I think the conductivity would be roughly equivalent to 2.5mm cable so the benefits of the bus are not as significant as they are in small scales, and the thought of all that soldering was a bit daunting. As it happens, we have assembled our layout without bus or clamps, but with conductive grease on the joiners. We have recorded a 2V drop on a 5A load at the centre point of a 100m loop. We will run another feeder to that central point and see how it goes.
Bill

 

[DafyddElvy]

Thanks as always for all the replies, appreciated as always to help me decide what I want for me.

An initial Digitrax SDX0487 is on order, it states that it is designed to work on G Gauge systems, and although I am unlike to use the function on the layout, the SDX0487 is a series 7 decoder meaning it has transponding functionality which will be useful in the garden.

What I'd like from my garden line and layout is probably quite different from most people, and if what I install seems a little more than is required at least I'll know my belt n braces approach will give me the reliability I want.

The plan was to pour concrete last weekend, however the good weather was to much of an invite not to be enjoying the great out doors we have here, so modelling was limited to base board building, but that's the boards built and waiting for some trestles to mount things on. The other not totally unexpected challenge is that the sitting room is to small, but for now I suspect that's something I'll need to live with, the hallway is just about wide enough but I might meet some resistance to that option, although we do have sunken spot lights in the hall way and replicating those under the baseboard wouldn't be too difficult, but that's a whole nother topic for another day.

The photo shows the (planned) scenic boards on their side with a modified Bachman tram on top, or on the side if you want to be picky, this was a useful exercise if only to prove to myself the boards will give me the opportunity to build something scenically interesting and worthwhile.

This project has now generated another member for the group, a person who unfortunately hasn't learnt the art of telling me when I might, just might, be going a little OTT with my ideas, Ross only joined at the weekend and he can be a little shy at times but I do suspect he is going to be fully infected with the larger scale tram bug.
Ross will be working with me to collaboratively create something that we'll one day be able to exhibit. Ormsgill was and remains a big influence for me to venture in to building something other than just another street scene tramway, so I suppose I should give thanks for someone else taking the leap before me. And no I am waffling.

Any how, a start has been made for something indoors, and a decision to use DCC outdoors, I don't know if I should call that progress but things are progressing.


David

 

[DafyddElvy]

All the usual disclaimers, no relationship with royal mail, digitrax or their british supplier.

The digitrax SDX0487 arrived thismorning, after only being ordered yesterday morning, and it would have been rude not to take a break from work (sorry for the sweary word) and open the packet.

Offered up the decoder and speaker to the tram chassis, all seems to look good, the black box holding the speaker will go under the cross bar it's sitting on, and I'll need to give some thought as to what functions I want to control and the connection between tram chassis and the body, but I'm a happy chappy with this decoder so far.


David