In DC you're not really controlling each locomotive, you're controlling a section or "block" of track. When you put power to the track, all the engines in the block are going to move - all the same direction, if they're wired up correctly. There is no way to isolated and control one engine with one power pack and control another engine with another power pack in DC.
This could be misleading for a newbie: of
course it's possible to independently control one loco at the same time as another, using separate power packs - that's the purpose of block control. Generally, this is done when there are enough operators to control each separate loco (or block).
In DCC (digital command control) there is a constant 12-14v AC power on the track. Each engine has it's own decoder and you can control each engine separately, or you can change the settings to have one throttle control two or more engines at the same time.
I think that this is both the strength and the weakness of DCC. The positive side of the arguement is that
multiple operators can control
multiple locos, each independently of all the others. Operations can be much more true-to-life.
The downside, in my opinion, is that it allows one operator to run more than one train at a time, meaning that the operator is operating one train, while the system runs the other(s). The whole point of operation, as opposed to just running trains, is being in control in order to accomplish the task at hand.
There's nothing wrong with just running trains, but, even then, why wouldn't you want to enjoy all the aspects of that running train: watching it thread through your trackwork or beautiful scenery (or through the beautiful scenery that you envision in your mind's eye, as the real thing has yet to be built), and just being in control of the train. Another train running becomes, at worst, a distraction, or, at best, something to ignore. Multi-tasking abilities aside, the second train is stealing from your enjoyment of the first.
:-D
So...in DC, you can run a train with several engines, but they're all going to respond to the power pack's commands if they're all in the same block - all will go forward, or all will go back. If the engines run at the same speeds (that is, if say all the engines go about 35 scale MPH when getting 6v of power) then they can all run together on a train. (In DCC, you can adjust how the engine responds to the power it gets, so that it is much easier to get several engines to run perfectly together.)
All good points, but for lone operators, block control isn't really necessary for operation. Usually, the ability to kill power on passing sidings or loco storage tracks will suffice.
Also, it's not really that difficult to match locos, according to their running abilities, using DC, and this task itself can provide a lot of enjoyment, if you're into that sort of thing.
It's my opinion that many lone-wolf operators opt for DCC mostly for the sound and consisting capabilities, but that the true operational advantages of this type of control are otherwise wasted.
Fortunately, our hobby has room for both ends of the control spectrum, and all of the various nuances in between. The common bond is the trains. :thumb::thumb:
Wayne