Need for Power

[lionelsoni]

Chris ("Birds") sent me this by e-mail:

Bob,

In a post about power requirements you wrote: 

"If you are using a single multi-train transformer, connect the outside rails of the two loops together at a few places around the room."

This is how I run my 6.5' x 14' two loop layout (more by accident than design).  Each loop has enough power, even at the farthest edges, using a single lockon for each loop.  It is powered by a single KW.  A second starter transformer powers six switches.  The common for the starter transformer is also tied to the common for the loops.  The transformers are in phase.

What does connecting the commons together a few times in this manner do to the circuit (as opposed to not connecting them together and sending each one back to it's transformer post)?

Chris

The reason for connecting them together is just to reduce the series resistance of the track.  Whatever resistance there is in the outside rails will be halved when the rails are in parallel.  When there are crossovers, crossings, and other connections between the tracks, you get this advantage anyway.

[lionelsoni]

I don't know any book to recommend. 

"What transformer(s). type of track, and track arrangement do you have?"

If you can give us a more specific description, we can give more specific advice...;-)

If you use 36-inch (K-Line) or 35.5-inch (Lionel) straights, there are far fewer joints.

Soldering isn't mandatory; but it does create very reliable connections.  Soldered rail can be unsoldered very easily.  In fact, I started removing track pins and soldering just because it is so much easier to remove track and turnouts without tearing up large parts of the layout.

 

[jimhaleyscomet]

CTT has a book called "Wiring Your Toy Train Layout".   It tells you all about blocks plus more!

 

Jim H 

[martinden]

Gee, Bob, I'd rather just run a few feeders than go around soldering each of the track joints(!). Especially if I planned to ever rearrange things and take the track apart.

[Anonymous]

However you arrange the feeds to the track, be sure to use wire heavy enough for the maximum current that your transformer will put out before tripping its circuit breaker.  For 16 AWG that is about 10 amperes; for 14 AWG, 15 amperes; and for 12 AWG, 20 amperes.

The track, with good connections between sections, is roughly equivalent to AWG 16.  For 70 feet of track, that is a resistance of 70 milliohms, which would drop about a third of a volt at 5 amperes.  Unless you're running very heavy trains or have poor connections, you should not need feeders.  I would try it without them first, then add them if needed.

Some things you can do to improve your situation:

Solder the connections between track sections.

If you are using a single multi-train transformer, connect the outside rails of the two loops together at a few places around the room.

If you are using two separate transformers and two separate loops, make the center rails common and connect them together.  This gives you two rails for each side of each circuit, instead of 1, 1, and 4 for the common.  Then arrange the transformer outputs to be out of phase with each other.  This way, the return currents cancel, also cancelling any voltage drop in the common center rails.

What transformer(s). type of track, and track arrangement do you have?

Bob,
You lost me at 'However'...

Are there any books that I could pick up to read about this stuff?  You seem to be a bit more knowledgable than the average bear when it comes to electricity.

Thanks,
Brent

[lionelsoni]

However you arrange the feeds to the track, be sure to use wire heavy enough for the maximum current that your transformer will put out before tripping its circuit breaker.  For 16 AWG that is about 10 amperes; for 14 AWG, 15 amperes; and for 12 AWG, 20 amperes.

The track, with good connections between sections, is roughly equivalent to AWG 16.  For 70 feet of track, that is a resistance of 70 milliohms, which would drop about a third of a volt at 5 amperes.  Unless you're running very heavy trains or have poor connections, you should not need feeders.  I would try it without them first, then add them if needed.

Some things you can do to improve your situation:

Solder the connections between track sections.

If you are using a single multi-train transformer, connect the outside rails of the two loops together at a few places around the room.

If you are using two separate transformers and two separate loops, make the center rails common and connect them together.  This gives you two rails for each side of each circuit, instead of 1, 1, and 4 for the common.  Then arrange the transformer outputs to be out of phase with each other.  This way, the return currents cancel, also cancelling any voltage drop in the common center rails.

What transformer(s). type of track, and track arrangement do you have?

[phillyreading]

Welcome Wildcat87, About 75 watts per train should do unless you have passenger cars, passenger cars use more watts because of the light bulbs inside them. Go with a ZW not a Z4000 and you can expand if you need to. For lighting only you can use an old transformer from a cell phone or cordless phone, do not power accessories this way. Also need to put additional power hookups about every six feet or about every five track sections. If it is a shelf layout you can hide the wire by using AWG (14 gauge wire)14/2 with ground mounted on top with wire staples, will give you three wires total and you can use the bare wire or ground for the outside rails, the black and white can go to track one or two. Lee F.

[chuck]

Length of track is not an issue, power consumed by the two trains is.  If these are modern can motored loco's and you are not running lighted passenger cars, you can get by on a lot less power IF you use multiple feeds of adequate gauged wire to the track.  While the track is conductive, it's not nearly as conductive as copper wire.  If you run six feeds per loop with 16 gauge speaker wire you shouldn't have any problems.  If you tray to shove 180 watts into each loop from one feed you will probably be disappointed in the results.

[Buckeye Riveter]

300 watts.

[Anonymous]

around a 15'x  20' room and two tracks / two trains

[RR Redneck]

How big of a set up are we talkin about here, are there to be any accessories, how many lines of track, and how many trains do you plan to run at one time?

[Anonymous]

Need info on amount of power required to run track around a room (Shelf Track)