Sounds like you have great ideas for your layout...but...
two ovals on a 4 X 8 board is going to mean that the inner
one will have less than desirable curve radius. I suggest you widen
to 5 feet and run a single track main with a minimum of 22" curve
radius...with DCC you can run one train clockwise
another counter clockwise on the same track...but you'll need passing sidings.

You don't need block control on a 4 X 8 layout. One 2 wire bus powers
the whole shebang. Track drops every 6 ft or so.

Signal control can be very complicated. Optical or Infrared sensors are the
simple way of occupancy detection. There are commercial devices
available.

You would need a separate power supply for turnouts, lights, and
other accessories. Many of us use discarded wall warts or an
old DC train power pack.
I would suggest Stapleton 751 D panel control switches for twin coil
turnouts. They have built in CDU to protect coils plus control panel and
signal lights.

A DIODE MATRIX system makes it easy to set turnouts for a route in
your yards. It sounds complex but is very simple...uses only barrier
strip terminal boards and a bunch of small diodes. One button sets
the points for all turnouts in the route.

Turning trains around requires a reverse 'loop' wye or turntable and an automatic
reverse loop controller which is available commercially.

Let us know how we can help you get started.

Don

 

How much of the electronic wizardry do most people put in to start?

I would say that most people do basic track power and turnout control and stop there. I would guess that less than 10% of people go beyond that.

When you start talking about block detection, that's only necessary if you're going to do computer automation and/or realistic signaling. When I started my layout, I knew that I wanted to do computer automation, so I planned for block detection from the start. There are multiple ways to do block detection, such as current sensing, infrared detectors, or magnets & reed switches. I chose to use current sensing for my block detection. If you're going to go that route, I think its easiest to plan for that from the start before laying track. That allows you to plan for where block boundaries will be and put insulated track joiners at those boundaries. You can then have power feeders for those blocks already installed, even if you don't put in the detection circuitry until later.

You should know going into block detection and signaling that it can get expensive very quickly. It also gets much more complex than just straight up DCC systems. In my opinion, to get realistic signaling, you'll need to have a computer involved to run the logic necessary to turn the signals on and off appropriately.

Mark

 

I can't speak for most people, but I can tell you that in my case I'm strictly a do-it-myself train runner. I line my routes manually. I am about to add signals, but no block detection, just the lit LED showing for effect. I want to keep it simple and less costly. So, bamboo skewer serves to line points and to separate car couplers, and I have no points motors, no wizardry, just that bus and feeder complex with a lot of wrapped bared wire end and solder covering them. Paying all that money and then sitting and watching things happen is fine, like with the grandkids at a paid museum, but not for me.

 

I am just finishing up the track on my first layout. I run N gauge on a 4x8 sheet of plywood. It is five loops with cross overs between three, a siding on the inner of the three loop, and the outer loop breaks down into a five rail yard and then comes back together. The two inner most loops are for a trolley line where my town will be when I get to buildings and scenery. I use DCC for it.

What I did for wiring is the power drops to a bus for all of the tracks to connect and get a good feed. I wired all of the turnouts to the appropriate switches to control them. I paired up some turnouts to run together so I won't have a train overrun an incorrectly set turnout, such as one end of the siding, etc. I saw all this as the minimum to get the layout to run correctly and should be done at the start. I don't have a reversing loop, but if I did that wiring would also be necessary at the beginning.

I am not currently planning on any signalling or occupancy detection in this layout. The only future change I am not yet sure about would be controlling the turnouts with the DCC system. Digitrax makes the DS64 decoder that would make that change fairly easy if I decide to do it.

I have thought about signalling and it looks like it might not be too hard to add it later if I change my mind on it. There are lots of videos on YouTube showing people adding sensors and things into already completed layouts that make me thing it can be done without too much damage to your layout.

Of course, I like to run trains more than build extras into it. My son will be doing the scenery and buildings for it because he likes to model more than run trains. A very good combination for us.I would suggest that this is the key point to your decision. Do you want to run the trains and maybe add stuff later, or are you more into doing the layout completely first, where running the trains is not as important? Obviously you want to run the trains at some point, but is the modeling of more interest or is the running?

To help understand this question, when I was flying R/C airplanes, i knew some guys who loved to build very detailed scale models and then sold them. They weren't interested at all in flying, the modeling was their thing. Other guys hated building but loved to fly so they would buy already built or nearly built planes. I would imagine the same goes for train people.

 

Steve brought up a most important point. How do you visualize your train operations? Some like to just
start a train going around the layout while they lay back and sip a toddy...many of us enjoy the much like
Chess challenges of switching operations...and of course, a combination.

Since you are planning a large yard, that seems to say, that you are thinking of keeping your
switcher busy. If so, you'll want to make sure you have a number of spurs that serve
businesses using rail freight...not just big factories but small outfits like an oil dealer or
a construction supply co. Perhaps a food wholesaler...and of course, a Less than
carload freight office.

The attraction of our hobby is that it can be whatever whets your appetite.

Don

 

Having just completed the Grand Valley layout, I'd say your plan is pretty aggressive for HO. You'll likely have lots of 18" curves which will limit yourself to small wheelbase consists. Many manufacturers say their locomotives will run on 18" but that doesn't mean they run well. Just be forewarned that to do HO on 4X8, you'll need to keep it pretty simple.

 

I agree with some of the other posters here: your plans are much too ambitious for the space you have allocated. A layout such as you envision will require a couple more feet in each direction; or better still, a layout that does not conform to a rectangular shape. Play around with some designs before you get too committed. Or switch to a smaller scale. Investing in a good layout planning software tool may help you get your arms around what will fit and what won't.

I'll also do Don one better: you don't even need a power bus and feeders for a typical 4x8 layout. A single pair of feeders will work. Yes, you will get a more reliable power supply with a few more drops, but it's not strictly necessary. Similarly, power districts are only necessary on larger layouts. Block detection is a different animal. Since it requires isolated track segments, it's best to plan it from square one.... BUT you're not going to have room on a 4x8 in HO for anything resembling true block occupancy rules. Same with signaling.

Turnout motors are nice. Plan for them ahead of time, by ensuring that there are no obstacles under the layout where you need to put them, and by drilling a hole for the actuating wire under the turnout points BEFORE you lay your track. You can add DCC route control them later, too, but do you really want to? I prefer to throw them from a pushbutton on the fascia. I think it better simulates putting a crew member on the ground and throwing it manually. Of course, I like to see my trains behave like the real thing, appropriate to the era I'm modeling (mid 1950's), so there wasn't a lot of automated route selection available. Your interests may differ.