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New DC wiring model railroad questions

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  • Member since
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New DC wiring model railroad questions
Posted by FrankG on Wednesday, May 1, 2019 4:37 AM

Hello all, new to the group here. I am currently building a model railroad with old school dc, and have some questions Im having trouble answering myself. Just for starters I have Andy Sperandeo's "Easy Model Railroad Wiring" book.

1) How is the connection from the throttle, to the bus usually made? Im going to run solid  14awg wire (for the bus) with 22awg feeders (to the track from the bus). Does one usually just wrap the solid 14 right to the "DC" screw terminals on the throttle? I would think forked stacons (in stranded 14awg) to a terminal block to accept the solid 14awg?? Hmm

2) When isolating a section of track, does one run the feeder, or the bus, as a "switch leg" to the switch (spst), if in fact the switch is going to be located remotely as opposed to in close proximity to the track section being isolated? Hmm

Thanks again in advance. FrankG

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Posted by BigDaddy on Wednesday, May 1, 2019 9:27 AM

Welcome to the forum.  Your intial posts are moderated, so expect a delay.

DC is so far in my rear view mirror that my Linn Wescott How to Wire Your Model Railroad has a Jiffy Lube coupon for $45 brake pad replacement that expired in 1988.

Is your layout big enough to need 14 ga for DC?  You will find 14 ga solid is stiff to work with but easy to solder on. 

Sta Kon is a brand of crimp on connectors.  In DCC world we would put our power in the middle of the bus so instead of having a 20' run from the end, it would only have a 10' run left and right.  So a terminal block would work.

I'll pass on #2 and let the DC guys opine.

This is a neat tool for your project

https://youtu.be/o9EdPiEoXM0

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by IRONROOSTER on Wednesday, May 1, 2019 9:54 AM

This sounds as though you are running one train at a time.  That being the case 14ga wire is over kill unless you have a very large layout.

1) But yes you can wrap the wire around the terminal.  I would prebend it using a screwdriver shaft or other rod.  Alternatively you can use a short piece of smaller wire like 18ga and connect it to the terminal at one end and the bus at the other.

2) I would run a feeder wire to the switch and from there a feeder to the track.  If either of these are a long distance you might want to use 18ga wire.

good luck

Paul

If you're having fun, you're doing it the right way.
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Posted by mbinsewi on Wednesday, May 1, 2019 9:56 AM

Welcome to the MR forums.  No need to consider DC as stricly "old school".  It's a fine way to run trains.  We all used it for a long time.

I have no idea what's in Andy's book, or what he shows, and how he does it.

There are many ways to wire DC.  You can have control blocks, you can use common rail, where only one rail is isolated between the control blocks, you can isolate both rails between blocks, not using the common rail rail method,  or you can just hook the buss wires to the power pack, and have the whole lay out live.

If you could post a diagram of what your building, it would help.

Mike.

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Posted by ROCK MILW on Wednesday, May 1, 2019 10:08 AM

Hi Frank,

My layout is DC with toggle switches controlling track power to a signaled double-track mainline.  Each main has five blocks.  The blocks are parallel to each other.  One of the blocks has a set of crossovers.  I have two MRC 9950 powerpacks for the mains.  Photos are here: https://goo.gl/photos/3JVZWi6NgCkk9GNbA

Questions:

1) Each block is powered by 16 ga solid wire, except where it goes through the Dallee detectors (22 ga there since the detector hole is small and multiple wires go through some detectors for the CTC signal system).  I could have used 18 ga but I thought I might convert to DCC someday so I went with 16 ga (layout is pretty small).  The 16 ga wires are inserted into the backs of the MRC 9950s and tightened down with screws.  I would feel comfortable wrapping the wires around a stud, if that's the type of connection.  I run multiple locomotives on one throttle (MU'd).  Track feeds are 22 ga solid, soldered to track, twice per block.  Runs like a charm.

2) Yes, each block is a switched leg, and is switched at the CTC panel.  Power runs from MRC 9950 to Dallee detector (+ only) to DPDT (center off) switch to block feeders.

I also used Andy Sperandeo's book--it is a great resource.

Brian

 

 

 

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Posted by RR_Mel on Wednesday, May 1, 2019 10:36 AM

Welcome
My answer will draw a lot of flack but here goes.
 
You didn’t mention what scale you will be working with, the following is for my experience in HO scale.
 
I built all of my layouts (HO) since 1951 using #18 or #20 solid feeders as home runs from my control panel to each block.  There can only be one consist operating in a block so the current will be low (in my case two locomotive consists max = about one amp) .
 
#20 AGW is rated at 1.5 amps and a 10’ run has less than .09 volt drop which isn’t a problem for my HO locomotives.  A 30’ run of #18 has a .28 voltage drop at 1.5 amps.  My longest run on my current layout is a bit under 15’ and at 1.5 amps the loss is .15 volts using #20 AGW wire, I have no problems running any of my trains.
 
That covers my layout operating in DC mode, I cut over to DCC in 2006.  I can run in either mode, DC or DCC.  When I turn on my DC power pack the accessory output 15 VAC operates a 12 DPDT DC relay through a bridge rectifier that switches the rail power from the DCC controller to the DC power pack automatically to prevent the two systems from coming together.
 
That said my layout wired for DC operation works perfect in DCC mode too.  If you plan on going DCC later on your DC wired layout will work OK without making changes.
 
When I was originally cutting over to DCC I rewired my layout by the book with the recommended Buss and Feeder system.  That caused me no end of problems.  I lost all of my occupancy detection and many of my turnouts had problems.  I backed up and rewired my layout to the original DC system and everything worked great including the new DCC system.
 
The DCC data rate is low speed and not rocket science type data and doesn’t need Cat-5 wiring.
 
Bottom line is my layout has never given me any problems using the DC wiring so running a large buss is a total waste of money and time.  If your layout will have 50’ home runs # 16 AWG wire should work great.
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by davidmurray on Wednesday, May 1, 2019 3:29 PM

Frank

My layout is 12' by 17'.  I have three cab, wireless throttles, with the blocks being controlled by rotary switches.

Each block has a terminal strip with wires brom the power source daisy-chained half way around the layout  (twenty odd feet), using #18 wire.  From the terminal strips to the rotary switches and then to the track I used Telephone wire, I think 26 guage, it was free. Of couse each track block has plastic rail joiners on both rails.

The only problem in 16 years is rotary switches wearing out.

Dave

 

David Murray from Oshawa, Ontario Canada
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Posted by FrankG on Wednesday, May 1, 2019 3:55 PM

Thanks Henry. Thats funny. Wasnt Linn Wescott the guy on the cover wearing an engineers hat smoking a pipe? lol Im an electrician so I have access to 14awg solid wire. Good info feeding it from the center of the buss. I chose DC originally because of a limited budget. If money was not an object I would of chosen DCC. Maybe i will reconsider at some point. Thx

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Posted by FrankG on Wednesday, May 1, 2019 4:01 PM

Thanks Paul. The RR is two folded dogbones, 42' end to end. I plan on locating the electrical control switches at one location so some of the isolation"switch legs" will have some distance, hence the reason I was asking about running the feeders or the buss ( wire guage) to the actual switch. Thanks for you reply FrankG

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Posted by FrankG on Wednesday, May 1, 2019 4:08 PM

Thanks Paul, I will try and draw out my track plan and post it. The trouble im having, is that the RR is basically two folded dogbones with two "double crossovers" so I can run a train into the inner dogbone (from the outer) and also change direction. Im wondering where I would actually gap the two rails efficiently (for the reversing loop) and plus accomadating the two double crossovers. Tough to explain without a drawing I know. Ill post it asap. Thanks again for your reply. FrankG

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Posted by jjdamnit on Wednesday, May 1, 2019 4:12 PM

Hello All,

Another resource you might consider is the Atlas book The Complete Atlas Wiring Book.

When getting back into this great hobby this book was one of my first resources for wiring. This book covers DC wiring from basic to multi-cab control along with wiring for turnout control.

Yes, it does promote the Atlas products but it also gives schematics if you choose to use other forms of control i.e. SPST, DPST and/or DPDT.

The concept of bus wiring is for DCC to avoid voltage drop caused by the rails.

For multi-cab control you will need to establish isolated power blocks. On my 4'x8' pike I had 16 isolated power blocks. One was as small as a single piece of 9-inch track.

You will need to be able to switch between cabs to each power block(s).

There is not enough space to completely describe how to wire this.

One thing I discovered was the money I could have saved on wire to each power block I could have bought an entry level DCC system.

The old saying is, "With DC you control the track with DCC you control the locomotive."

I would seriously consider DCC over DC if you are planning on running multiple locomotives simultaneously.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by FrankG on Wednesday, May 1, 2019 4:18 PM

Nice looking RR, and nice looking wiring. What is the "canopy glue" pictured and also what are the three position switches you employ?

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Posted by FrankG on Wednesday, May 1, 2019 4:22 PM

Good info Dave thanks. I plan on posting a photo drawing of the track plan. FrankG

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Posted by FrankG on Wednesday, May 1, 2019 4:28 PM

Thanks Mel for all the info. I plan on posting a drawing of the track plan. It is HO scale, 42' long (end to end), and is basically two folded dogbones, with two double crossovers, to allow entrance (and exit) into the two individual loops and to change direction. My question is where to efficiently gapp the rails for the reversing loop (s) and how does the double crossovers play into the scheme. Difficult to explain without a drawing I know. I will post asap. Thanks. FrankG

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Posted by ROCK MILW on Thursday, May 2, 2019 9:08 AM

Thanks, Frank.  For the CTC panel I purchased LEDs and bezels from Logic Rail Technologies.  The canopy glue was my first attempt at fastening the bezels to the panel.  I didn't like how thick and viscous it was (perhaps the bottle was old) so I switched to white glue which worked well.  The three position rotary switches were also purchased from Logic Rail Technologies.  They also sell a Utah Pacific-produced detent cover that converts the rotary switch from a three position to a two position configuration (i.e., for the N and R turnout conditions.)

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Posted by doctorwayne on Saturday, May 4, 2019 1:18 AM

Welcome to the MR Forums, Frank!

If, like me, you plan on running only one train at a time, there's no need at all for a bus wire, and multiple feeders.
I have just under 300' of track, not counting the double track through all towns, industrial sidings and staging yards.
I use an MRC Controlmaster 20 for power, and run trains, usually with multiple steam locomotives, using a Stapleton pwm walk-around throttle.

Here's my connection to the track...

All rail joints, other than insulated ones, are soldered.  Obviously, such a set-up isn't suitable for running multiple trains at one time, but I'm not set-up to run them either - a train in motion needs the operator's undivided attention.  While most trains aren't all that long, most require helpers and/or pushers, due to the many grades and curves. 
The only time trains slow is when I adjust the thottle to slow them.

If you are planning to run multiple trains using block control or something similar, ignore my input.

Wayne

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Posted by FrankG on Saturday, May 4, 2019 6:59 AM

Very good input Wayne thanks for your reply. The MRC Controlmaster 20 is just the one I was looking at to purchase. Thanks again. FrankG Yes Thumbs Up

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