Digital for absolute dummies?

Henri

Henri

refuses to grow up
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Can someone point out WHAT digital means in relation to model trains? I'm aware you can address each component on your track (loc, points, etc) individually and this way, operate them.

Is power supplied through the tracks? Or battery?

How is the digital signal transferred? By RC or by track?

What do you need to 'get started'? When you have an DC powered layout and DC only loco's?

Can you RC your loco's? Is this still digital? Can you have DC power through the tracks and speed control / direction / other functions by RC?

I can see the possibilities but I have no idea where to start looking!
 
To use DCC (digital) the main benefits over DC are you can have more than one loco on the same piece of track at the same time, you have full voltage running all the time so less problem with voltage drop, and lights and sound running when the loco is stationary. If you have DC you need a digital command station (many manufacturers, cost from EUR 100 upwards) and DCC decoders in each loco (costing from EUR 30 upwards) and for each point of signal (called accessory decoders). Both LGB and PIKO have guides for DCC for beginners (LGB call it MTS or MTZ). This is a big topic to cover in a forum reply.
 
DCC supplies foll AC voltage to the track all the time, the central station then sends 'coded messages' through the AC supply to a chip in the loco which converts the AC to DC and operates the loco as commanded.

Costs more that analogue but its good and the extra power (I use a Massoth with 10 amps) should give more reliable running.

The more complicated your layout the easier digital makes your life.

All opinions voiced here are my own.
 
Digital simply means the control signal is electronic binary 1s and 0s, and analogue means equipment is controlled by a continuously variable signal eg. voltage.

NMRA DCC (Digital Command Control) is an example of a digital system for model railways. There are other similar but generally incompatible systems, however DCC is arguably the dominant standard. LGB's MTS is a variant of DCC and generally compatible (with a few quirks).

Good old DC is an example of analogue control.

Yes you can have RC systems which are digital and RC systems which are analogue control.
 
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Hi Henri,

I can answer your questions about DCC (Digital Command & Control) very briefly for now.

Henri said:
Can someone point out WHAT digital means in relation to model trains? I'm aware you can address each component on your track (loc, points, etc) individually and this way, operate them.

Yes each item is controlled individually and separately by one controller.

Is power supplied through the tracks? Or battery?

With Digital DCC - through the tracks

How is the digital signal transferred? By RC or by track?

By the tracks

What do you need to 'get started'? When you have an DC powered layout and DC only loco's?

A Digital (DCC) starter set plus at least one DCC decoder for each loco or other item.

Can you RC your loco's? Is this still digital? Can you have DC power through the tracks and speed control / direction / other functions by RC?

You can run your locos by RC with analogue or digital control in the transmitter and receiver and with battery and/or track power. But this is not generally known as digital.

I can see the possibilities but I have no idea where to start looking!
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I'm afraid a it's a big subject and there is no easy answer
 
Plenty of good answers so far, I will try to add to them without confusing you even further.....

In a DCC system, each loco (and, if you wish, each point, signal and other device) has a circuit board installed called a "decoder". You can buy some locos with decoders already installed, but fitting decoders to exisiting non-DCC locos is reasonably starightforward in most cases (some are simple plug-ins, others are more complicated, but that's a whole world of its own).

The "Central Station" or "Command Station" takes the place of your simple analogue DC controller, in that it is connected between your main power supply and the track; some systems have all the controls on the Central Station itself (eg the new Marklin CS2/CS3 system), others have a separate handset controller like the Massoth Navigator, which is linked to the Central Station either by cable or by wireless link. The Central Station is basically a computer as well as a power supply, but don't let that scare you!

The Central Station delivers full voltage to the track all the time, in the form of a VERY fast cycle AC (much faster than household mains AC cycles) - and it transmits information along the track by varying the pulse spacing of the AC, but that is all Arcane Magicks that none of us really need to understand - all you need to know is that it works....

Now, each decoder (let's just consider loco decoders for the moment) has an "address" - that is a user-programmed number, usually of two digits but potentially up to five digits (don't worry about that for now), which identifies that decoder; so let's say you have your Stainz and your Elias tram, and you've installed decoders in both of them. Say you've given your Stainz address "01", and your Elias "02".

If both of your locos are on the track at the same time, under DC power if you turn the controller then both will move. Under DCC, they don't - each will only respond to information sent through the track that is meant for that loco's particular decoder address.
So, if you select address "02" on your controller, and then turn the speed knob, ONLY the Elias tram will move - the Stainz will still get the same signal, but it will ignore it because it is not addressed to its loco address.
You can then LEAVE THE TRAM RUNNING, and select address "01" - you can then tell your Stainz to do something while the Elias is still happily trundling along at the speed you set for it! When you want to take control of the Tram back and stop it, select address "02" again and you have control back, while the Stainz is still doing whatever you told it to. You can, in theory, do this for as many locos as your system has power to run at the same time - and don't worry, there is always a big "EMERGENCY STOP" button that stops everything on the layout dead if you need to, like if you get in a panic about which loco you are driving at that moment!

There is, of course, a lot more to it - but I hope that has helped to make it clearer rather than more confusing..... the most important thing is that usually, it just works; like all the best technology, it does very complicated things in the background so that you get a simple experience of driving your trains and having fun.

Jon.
 
Henri said:
This all makes sense, guys! Thanks!

What I understand it is something I can add later on in my process of becoming a Garden Railway enthusiast...
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Yes, exactly. At any point, you can decide to change over to DCC, and most of your locos will be capable of being converted by having decoders installed (I've never actually seen it done in a growler, but I don't see any reason why it shouldn't be possible!). One thing to consider is that if you do decide to make the change, it would be better done before you collect TOO many locos - installing decoders when you've got three or four locos isn't too bad cost-wise, but if you wait till you've collected a dozen or more then it starts to get very expensive.... ;)

My advice would be that if you ever want to buy yourself a really nice "special" loco or two (perhaps ones with sound installed), then even though you will still be running them on DC for a while it would be worth getting ones that are already DCC fitted. Almost all locos that have DCC decoders will also run on analogue DC quite happily, and when you do make the big step up to DCC then you've already got some locos that you can operate straight away....

Jon.
 
That's a very useful diagram from PaulRhB, but just ignore the "booster" boxes - you don't need to worry about them until you have a VERY big layout, OR if you're using a Command Station that is not really designed for running large scales! Other than that, it's a very good graphical representation of how it all fits together....

Jon.
 
It sounds pretty easy. I think I do understand.

When you are going for digital, are all systems compatible?

And is there any form of feedback possible so the controller 'knows' where the different loco's are on the track? So the Elias will stop at a platform, for example? Or is this something different?
 
Henri said:
It sounds pretty easy. I think I do understand.

When you are going for digital, are all systems compatible?
Click to expand...
DCC components are compatible at the track because the DCC signal messages in the track are standardised, ie. you can buy any brand of DCC decoder suitable for the scale of trains (built for sufficient volts and amps) and it will work with your DCC command station. It's more difficult to mix brands of throttle or other controlling components of the system because the command station manufacturers may use a proprietary control bus design between their boxes.

And is there any form of feedback possible so the controller 'knows' where the different loco's are on the track? So the Elias will stop at a platform, for example? Or is this something different?
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Yes you can use feedback modules, it depends on what your command station supports because there are different feedback bus designs for connecting the modules into the system. More typically feedback modules are used with computer control of DCC.

There is also the concept of "Brake on DC" where some loco decoders can be programmed to come to a gentle stop if they see a DC voltage, and start off again when they see DCC in the track. This can be used to stop at a red signal for example.
 
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PaulRhB said:
It does say that on the diagram ;)
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Yes, point taken Paul.... I just felt that as a VERY basic diagram of how the elements of DCC connect together, the presence of the booster units at all (even with the explanatory text) possibly risked confusing rather than clarifying the issue... :)

Jon.
 
ntpntpntp said:
There is also the concept of "Brake on DC" where some loco decoders can be programmed to come to a gentle stop if they see a DC voltage, and start off again when they see DCC in the track. This can be used to stop at a red signal for example.
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I tried Brakeon DC outside and found it to be a real pain. You have to have a DC power supply for each braking area, fine inside where you can share one supply between sections but a reet pain outdoors over any distance.
I use ABC braking now because the brake modules for it uses cheap diodes. An easily done home made brake module comes in at around a pound!
Not all decoders support ABC but it's worth looking for those that do.
 
Worth considering now that you have some of the Basics. You can get LGB Parallel Systems (LGB 2 effetively) at pretty good prices second hand now that a lot of people have upgraded to LGB 3, New Marklin and Massoth. Just make sure all the kit has a P in a Dot on it. Ask if you buy from Ebay before you bid.
JonD
 
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