My layout is in N scale, with an 85 foot double track main, a 12 track storage area, small yard, and engine facility.
The layout measures 10 X 14 with two helices.
There are a total of 34 engines, many of which are with their trains in the storage area.
All of the already made-up trains (11) have two or three engines on them, ready to be brought up via a helix to run on the railroad.
Currently, the road is divided into six parallel blocks (DC); 12 blocks in all.
In the future, I plan on adding a track signaling system.
Due to space limitations, only 3 people could operate at any one time.
There just isn't room for any more without getting in each others way.
Which Digitrax system would be best for me? Would the Zephyr be enough?
On the face of it, Zephyr would be enough from the three operators' perspective.
However, since you have several trains with multiple locomotives, the DCS50, DCS51 or DCS52 will not be enough.
From what I have read, the Zephyr (DCS50) can control up to 10 locos, DCS51 and DCS52 can control up to 20 locos.
If I were to have all 30 some locos with decoders, does that mean I could only address ten at a time, or would I only be able to have ten decoders in the system total?
Zephyr has ten "slots", which means that the system is able to handle ten locomotives at any given time.
Since you have eleven trains, each with multiple locomotives, you would be able to handle two or three trains only.
In a multiple unit situation, each locomotive in the consist is assigned a slot, with the Top locomotive being the master locomotive and the others attached to the commands given to the top locomotive.
Your eleven trains will have at least two locomotives each, so you would need 22 slots.
Interestingly, the Evolution Express has 22 slots in its Factory-configuration, but this can be expanded to 100 slots.
This will be enough to accommodate your thirty four locomotives.
And what about running engines in some of the consists that don't have decoders?
Digitrax systems can only address one analog locomotive, at address 00.
The general feeling among Digitrax operators is that controlling an analog locomotive in this way is usually not satisfactory for a variety of reasons.
Typically, such control is reserved for locomotives that are small and thus cannot be easily converted to DCC.
In the case of the trailing units in each of your train consists, these could be equipped with simple decoders; this could be DN146 or, if the locomotive does not draw too much current, DZ126.
In this situation, the top locomotive of the consist would be equipped with a higher level decoder, possibly including sound decoders.
Power Consumption
This brings up the issue of power needs.
Since you have many locomotives, even the Evolution by itself will not be enough to power your railroad.
In addition to the 5 amp or 8 amp Evolution, you will need to add boosters, subdividing your railroad into enough power districts to handle the load.
Please see the related articles below.
I suspect that I would need the ability to use wireless control also.
With all Digitrax systems, tetherless control can be added at a later date.
Both the DT500 and UT4 are InfraReady, which means that you can add a UR90 to your LocoNet and have tetherless control.
You can also add radio control with the addition of a radio throttle and UR92 or UR93.
These units can also handle infrared signals.
Signaling
You mention signaling, and as you rewire your railroad into the various power districts, you should keep that possibility in mind.
Even if you never do install the signals, by doing it now, you won't have to go back later and redo what you have already done.