length of layout vs. power needs.

[baron]

I am relatively new to model railroading.  I am building a new layout and the outermost track on my O gauge layout is 180 inches long and 88 inches wide.  What type of transformer will I need to power a 3 passenger car and a steam 2-8-4 around the entire outer track?

[Desertdweller]

We are going to need some more information to answer your question.  The dimensions of your outermost track do not sound overly large, but how many feet of track do you intend to power at the same time (total length)?

Do you have grades, or is your railroad flat?

Is it AC or DC?  Or DCC?

Are your passenger cars lighted?

Do you intend to power additional things with your power supply (static lighting, switch machines, etc)?

Les

[jbrock27]

It would probably also be better if this question was moved to where O Gauge topics are discussed.

[baron]

Hi, I am currently familiarizing myself with this site. Please bear with me.  In answer to Desertdweller reply, the over length of track involved is 48 linear feet.  It is flat and I do not, presently, intend to run anything other than the train.  The passenger cars are lighted.  I did some research and I believe I need to utilize one or more busses, but I haven't located any info on the net that explains the wiring.  Help.

Thanks,

Stan

[jbrock27]

No worries Von Richthofen, not a criticism of you, just a suggestion to get you to the right place, for the right help.

Good luck with getting your help!

[Desertdweller]

Stan,

I model at the other end of the spectrum: N-scale DC.  So I can't help you with specific powerpack recommendations.  You are right that you should have buss wires, as 48 feet of track is too long to feed from two wire connections.  My DC railroad uses the "common rail" wiring plan where one continuous rail (the "inside" or the "outside") acts as one side of the circuit.  This rail is fed from a buss wire that parallels the track on the underside of the layout.  Jumper wires from this wire connect to the "common rail" every three or four feet.

The other half of the circuit is provided by wires running from dpdt selector switches to insulated track blocks on the opposite rail from the common rail.  If you have a long "block" you may need an additional feeder wire on the controlled side.

If you have AC for train power, you could wire the layout with a buss wire/feeders for each rail and side of the circuit.  You would still have to divide one rail into insulated blocks if you want to control more than one train at once, or if you want to leave locos on the layout without power being fed to them. If that is the case, it would be wired like a DC railroad with the buss on only the common rail side.

If you have DCC, you are still not on your own, but you will need to get your advice from someone else.  When this system first appeared, I made a decision not to use it and did not incorporate it into my current railroad.

The answer to how big a power supply you will need boils down to how much amperage you will be using.  Anything that increases load on the power system will require additional capacity in any power system.  Bear in mind that "trainset" power packs are usually the minimum required for the equipment packed in the set.

It is very important in the planning stage to decide what you eventually want your model railroad to be like.  If you will someday want to run additional locomotives, longer trains, or several trains at once, now is the time to design a system that will support that.  It is much easier to do this than to try to retrofit an existing railroad.

Les

[phillyreading]

I would say a decent 80 or 100 watt transformer will work, with a few power drops added in about every 4 or 5 sections of track to keep the electric flowing good. The length of the track don't mean how much power neede the amount of amps drawn will dictate it.
If you have 3 lighted passenger cars you may need a 100 watt transformer, but if you just have the engine and tender needing to be powered your power draw will be lower and an 80 watt transformer should work.
FYI; don't use a starter set transformer as it won't have enough power.

Lee F.