Train Control
The main difference between normal DC voltage control (analogue), and Digital Command Control is this....
With DC Voltage Control - you control the track, and the track controls the train.
With Digital Command Control - you control the track, and the train.
Look at this simple example:
Put the locomotive on the track, turn up the control, and the loco runs forward, increasing in speed.
Now, turn down the control until the loco stops. Take off the loco and turn it around, and turn up the control as was done previously
With DC Voltage Control, the loco runs in the same direction, but backwards. Its wheels are picking up a reversed voltage, making it run backwards since the loco has been turned round.
With Digital Command Control, the loco runs in the opposite direction, forwards. The reason being, is that the commands given to the loco from the controller have not changed, they require forward movement.
Point Wiring for DCC
I believe that most DCC modellers would wire the track so that a loco can pick up signals from anywhere on the track, including sidings where, under DC Voltage Control they would be isolated. This principle is used in the following point wiring.
Using Fleischmann track, do nothing - they are already pre-wired for DCC operation (do not convert them to ‘thinking’ points)
Using Peco track, if points are ‘electrofrog’ (recommended), then place an isolating joiner at both the centre frog connections (the connections which are switched when the point is switched). ‘Insulfrog’ points are already isolated and do not require separate isolation. Then, for either type of point, ‘electrofrog’, or ‘insulfrog’, apply a wire to the track run.
The only problem with this, is that if you run a train into a point which is set against it (in the diagram above, from track A to C, then it would short-out as it hit the point. Not just short-out its own track, but the whole layout electrics; this will include all other locos, and could also include point motors, signals, or any other electrical item that happened to be connected to the same DCC system. No damage will occur to your DCC controller - it is designed to take ‘knocks’; but it isn’t good if the layout is at an exhibition.
Note: You don’t have to wire sidings etc. as above, since the same isolating principles apply to DCC as for DC voltage control; no voltage - no movement!
This item is a draft, written by the Webmaster, to help anyone thinking of starting out with DCC.
Further, more detailed Articles will be included as DCC topics are covered in Club Talk Nights.
