DCC Conversion Reverse Loops

[phils2um]

I'm having trouble visualizing your proposed switch power bus. I've heard of some that run a separate DCC booster circuit for turnouts and accessories along with their track power lines. But, the switch decoders are still positioned locally near the turnouts to be controlled. If you locate all the switch decoders in your house you will need to run two wires, assuming EPL drives, for each turnout from the house to the switch. That's sixteen wires for the yard and 32 total just for the turnouts in the layout as you've got it drawn in post3! Are you sure you want to do that?!

By the way, Massoth 4 channel switch decoders do not need to be in a weatherproof enclosure - just protected from the weather and kept from being submerged in water. Mine are in Pola structures. The oldest switch decoder along with a LGB reverse loop module (which is physically identical to the Massoth version except color) have been outside year-round for four years now and both have been trouble free and are working fine. I live in Ann Arbor, MI so I doubt the weather is that much different than what you experience. I'll post a couple of pictures Wed. It's dark out now and I'll be otherwise engaged all day tomorrow.

 

[Diesel2000]

Good, we are now on the same page for current draw from the main line. Do the Massoth decoders allow separate power and DCC feed? I thought they were combined. Are you thinking of a separate booster running the decoders? I really think no matter where they go, I would run from the main track power.

Right, I agree the issues is weatherproof enclosures in multiple places. I use the gray plastic conduit junction boxes, designed for outdoor use. Easy and cheap, with a weatherproof gasket.

I don't think it is so much work, vs. I would say a lot more wire, but it is definitely your tradeoff to make.

In any case, sounds like you have it figured out, I just try for fewer and shorter wires, seems to result in lower maintenance, but heck, my switches are all pneumatic anyway!

Greg

Yes the Massoth decoders have combined DCC-in and power. I'm going to hook them up to a Tam Valley accessory booster connected to Massoth CS. If I decide to add lighting/signals around the layout this will come in handy for that application as well.

14 of the 16 switches in my layout design are clustered in 3 areas, so its possible to locate the decoders in a central area, I'm just not confident of the weatherproofing. I'm using the grey conduit junction boxes currently for my DC mainline hookup and even above ground there is some water that gets in. In the winter we get frozen ground for 3 months and that always causes condensation to form plus rain and snow.

It will be easy to run 3/4" conduit to the 3 switch clusters that go to a junction box on the side of the house and then into the basement. The 2 that are more scattered I could then use the single switch decoders and track power for ease of install, which are weatherproof. That might be the way to go.

I think this is coming together well now and am looking forward to getting started this spring on the build out. Having the winter to plan it all out and iterate through designs has allowed me to slowly purchase track and wiring items and spread the pain out.

 

[dunnyrail]

Yes the Massoth decoders have combined DCC-in and power. I'm going to hook them up to a Tam Valley accessory booster connected to Massoth CS. If I decide to add lighting/signals around the layout this will come in handy for that application as well.

14 of the 16 switches in my layout design are clustered in 3 areas, so its possible to locate the decoders in a central area, I'm just not confident of the weatherproofing. I'm using the grey conduit junction boxes currently for my DC mainline hookup and even above ground there is some water that gets in. In the winter we get frozen ground for 3 months and that always causes condensation to form plus rain and snow.

It will be easy to run 3/4" conduit to the 3 switch clusters that go to a junction box on the side of the house and then into the basement. The 2 that are more scattered I could then use the single switch decoders and track power for ease of install, which are weatherproof. That might be the way to go.

I think this is coming together well now and am looking forward to getting started this spring on the build out. Having the winter to plan it all out and iterate through designs has allowed me to slowly purchase track and wiring items and spread the pain out.

I think if you use some Silicone Resin to seal the joints (where wires enter and exit) both inside and out you ought to keep damp and miniature animal organisations out reasonably well. Just make sure that the box is well sealled and if some kinf of Plastic a Spray with Matt Black Car Acrylic Undercoat should do the trick.

 

[PhilP]

I would not spray anything, with electronics in, 'matt black'.. - I am sure the temperatures will be hot enough, without a black box around the electronics!

 

[Diesel2000]

I'm having trouble visualizing your proposed switch power bus. I've heard of some that run a separate DCC booster circuit for turnouts and accessories along with their track power lines. But, the switch decoders are still positioned locally near the turnouts to be controlled. If you locate all the switch decoders in your house you will need to run two wires, assuming EPL drives, for each turnout from the house to the switch. That's sixteen wires for the yard and 32 total just for the turnouts in the layout as you've got it drawn in post3! Are you sure you want to do that?!

By the way, Massoth 4 channel switch decoders do not need to be in a weatherproof enclosure - just protected from the weather and kept from being submerged in water. Mine are in Pola structures. The oldest switch decoder along with a LGB reverse loop module (which is physically identical to the Massoth version except color) have been outside year-round for four years now and both have been trouble free and are working fine. I live in Ann Arbor, MI so I doubt the weather is that much different than what you experience. I'll post a couple of pictures Wed. It's dark out now and I'll be otherwise engaged all day tomorrow.

I'd definitely like to see how you have those switch decoders set up outside. I'm just outside Chicago so our weather is similar.

Its a separate booster which I would hook up between the CS and circuit breakers. Its probably overkill, but I like the idea of the turnouts being isolated from the track power and whatever is happening in the yard and on the mainline.

It would be extra wiring to locate the decoders in the house. I'm using 18 gauge zip cord at the moment to test indoors as the EPL drives and the massoth switch decoders dont appear to be able to accept much bigger than that. Maybe 16 gauge, but I dont have any at the moment to try.

I dont particular fancy running the extra wiring, but have been having a tough time coming up with an enclosure setup that I like. Currently I have the CS mounted to a panel that I carry in and out of the house each time I run trains and hook up to the existing wiring using banana plugs (thanks Greg for that idea). It would be great to have it all set up from the basement so I just bring out the Navigator, and if I'm doing the work to get the track power set up in this way it doesnt seem like that much more effort to run the switch decoders there either, but I might be oversimplifying.

 

[Greg Elmassian]

Some hints about weatherproofing:

First, it is virtually impossible to have a completely hermetically sealed box, and if there is air inside, it will have some moisture.

It's best to have small weep holes in the corners of a box so any condensation that may occur will have an escape route...

As the box heats during the sunny part of the day, it will help expel any condensed moisture

You put the weep holes all corners so no matter which corner is lower, there is a drain hole there... just couple of mm is enough.

Painting a box black helps warm it up on sunny winter days, and as long as the electronics don't overheat (and most won't) it's actually better, but this is a fine point.

The other alternative is to completely encapsulate electronics, it can be done, but it is much more difficult than you realize.

Let it breath a bit and keep it above ground and you will be fine for years.

Greg

 

[phils2um]

As promised here are some pics of the Pola buildings I use to protect my switch decoders. Even though the view into the first looks like a rats nest of wires that's because there are quite a few wires coming and going. This building also has a reverse loop module in it. Thank you DCC; just imagine trying to run these all the way back to a control panel! The wires are:

a. one pair from the track to bring the DCC signal/power in - this goes to a terminal block

b. four DCC pairs from the terminal block powering the switch decoder, the reverse loop module, the track on the far side of the reverse module's polarity swapping track segment and a bridge rectifier for the building's led lighting.

c. four pairs out to the EPL turnout drives

d. four pairs in from the reverse loop module sensor segments (two more more than usual due to how I'm using it)

e. one pair of DCC power out from reverse loop module to polarity swapping track segment.

The second building is much more orderly and only houses a switch decoder and associated wiring along with a feed to the building's lights.

Next are a couple of shots of one of the turnouts powered by the decoder in the second building. The first shows the DCC/power lead connection from the track. I use ring terminals connected to Split-Jaw rail clamps. The second shows the EPL switch drive. The leads to the drive are coming from the decoder. A separate set of lines connect from the track to a bridge rectifier I installed in the turnout lantern that feeds a led bulb.

The larger building and switch decoder have been outside four years now through all kinds of weather including being buried in snow many times. Frost may occur on the outside of the buildings in winter but the decoders are protected and the roofs and walls keep the decoders dry in the rain. Finally, there is plenty of air circulation. I don't have any concerns about condensation.

 

[Diesel2000]

As promised here are some pics of the Pola buildings I use to protect my switch decoders. Even though the view into the first looks like a rats nest of wires that's because there are quite a few wires coming and going. This building also has a reverse loop module in it. Thank you DCC; just imagine trying to run these all the way back to a control panel! The wires are:

a. one pair from the track to bring the DCC signal/power in - this goes to a terminal block

b. four DCC pairs from the terminal block powering the switch decoder, the reverse loop module, the track on the far side of the reverse module's polarity swapping track segment and a bridge rectifier for the building's led lighting.

c. four pairs out to the EPL turnout drives

d. four pairs in from the reverse loop module sensor segments (two more more than usual due to how I'm using it)

e. one pair of DCC power out from reverse loop module to polarity swapping track segment.

The second building is much more orderly and only houses a switch decoder and associated wiring along with a feed to the building's lights.

Next are a couple of shots of one of the turnouts powered by the decoder in the second building. The first shows the DCC/power lead connection from the track. I use ring terminals connected to Split-Jaw rail clamps. The second shows the EPL switch drive. The leads to the drive are coming from the decoder. A separate set of lines connect from the track to a bridge rectifier I installed in the turnout lantern that feeds a led bulb.

The larger building and switch decoder have been outside four years now through all kinds of weather including being buried in snow many times. Frost may occur on the outside of the buildings in winter but the decoders are protected and the roofs and walls keep the decoders dry in the rain. Finally, there is plenty of air circulation. I don't have any concerns about condensation.

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Thank you for all that! Very nice to see someone else's inner workings from a similar climate. This is my first foray into an outdoor layout and DCC so these are the things that are really helpful. I built the mainline (green) last fall and have been operating just a single train on DC until now.

• Do you have an overall track plan you could share?
• How many turnouts and feet of track?

Also:

• What kind of connectors are you using for the EPL and switch decoders?
• What gauge wire? That appears to be about 18 gauge?

 

[Greg Elmassian]

18 Gauge too thin, do not scrimp on something you will have forever (or resist upgrading later) ... use 12 gauge... remember that resistance is the enemy of proper "circuit breaker" action. With longer runs and higher currents, 18 gauge is not appropriate for good operation.

Greg

 

[Diesel2000]

18 Gauge too thin, do not scrimp on something you will have forever (or resist upgrading later) ... use 12 gauge... remember that resistance is the enemy of proper "circuit breaker" action. With longer runs and higher currents, 18 gauge is not appropriate for good operation.

Greg

I was asking about 18 for the switch EPLs and decoders only. I'm not sure the EPLs and LGB/Massoth 4 channel decoders can accept anything bigger (maybe 16).

I plan to use 10 gauge for the track bus.

 

[Greg Elmassian]

That's what I use, and none of my feeders is over 40 foot, and I use home runs, not a bus, but I do have trains that can draw 10 amps.

Greg

 

[phils2um]

Hi Diesel2000, (By the way - do you have a christian name you wish to share with us?)

Here are answers to the questions you asked in post 28.

1. My current track plan can be seen in post #64 in the "Phil S' RR" thread in the "Large Scale Pictures" forum.

2. One circuit around the loop is 210 feet. There are currently nine turnouts on the line. 7 are controlled by two 4-channel switch decoders. Two have individual decoders because of their location.

3. The connectors are LGB #50131 Wire Terminals. They're very convenient to keep wire strands together and avoid the need to tin wire ends. Just put one on the wire end and give it a pinch with needle nose pliers to keep it in place. A pack of 50 is about $10 at Only Trains, or Reynauld's.

4. I am using a variety of wire gauges on the line.

The feed from the central station-booster in the house is four conductor 12 awg speaker cable in buried PVC conduit to an external junction box. Only one pair is currently being used. The other pair is for a second booster when I get around to it. I have 12 awg bus wires buried under the track/concrete block coming off a terminal block in the junction box. The bus wire is 2 standard THHN oil and gasoline resistant single conductor wires twisted together with about 6 twists/foot to help reduce DCC signal degradation. There are short LGB 51223 1.5mm^2 cross-section (roughly 16 awg) feeder wires soldered to the bus wires about every 2 meters. These attach to the track at Split-Jaw rail clamps.

Inside the first building in post 27 I used some 18 awg zip-cord (ex-speaker wire) for the sensor connections to the reverse loop module. DCC/power connections to and from the reverse loop module are short segments of LGB 51223 that connect to the terminal block in the building. Most of the rest of the wire is LGB 50140 twin-lead cable (roughly 20 awg) including the DCC/power to the switch decoder and the feeds to the turnout drives.

The switch decoder in the second building is wired with LGB 50140 twin-lead. Note: my longest EPL turnout lead is less than 10 feet. The switch decoder power leads from the track are less than 2 feet in length. The smaller gauge of the LGB 50140 twin-lead is of no concern in this situation.

The turnout lanterns are wired with a combination LGB 50140 twin-lead and some 24 awg hookup wire I had on hand.

The only thing I regret is where I located the external junction box for the DCC power leads from the house. It could have been located elsewhere which would eliminate about 35 feet or more of cable. My overall cable length was causing me all sorts of problems with DCC signal degradation resulting in runaway locos and switch decoders not responding, It is still not completely sorted. It took an oscilloscope to see what was actually happening (terrible ringing on the square wave form). I ended up installing a R-C terminator which greatly improved the signal but robs me of about 400 mA. My DCC signal still gets trashed if too many inductive loads such as incandescent bulbs (older LGB coach lighting) and/or locomotive smoke units are directly powered from the track. Lesson learned - do everything you can from the outset to keep the DCC signal clean. Like Greg said, keep your DCC power leads as short as possible.

 

[Greg Elmassian]

As an account of another outdoor layout, not a "one up"

• I have about 850 feet of stainless rail with stainless rail clamps, and it is sectional track, meaning a lot of separate pieces and connections.
• I have about 10 feeders, all are 10 gauge home runs, no joints between the command station and where it clamps to the rails
• EVERY power district is insulated from the others (important)
• I have 7 4-port Digitrax DS-64's fed from the rails at remote locations, which all drive 24 volt solenoids for the pneumatic switch motors.
• I used to used a 10 amp NCE system, now a 12/20 amp Zimo system, no issues with either.

No snubbers, no runaways, no issues... I do not twist my feeders either.

I think you see a difference here... if nothing else, keep your "power districts" isolated from each other, that is important to avoid signal corruption, and of course I try to feed power districts from the physical center, to minimize the distance the signal must travel. (you do not want a locomotive to be able to receive a signal from more than one direction)

Now, it does turn out that SS rail is better for DCC than brass, so that may be playing a part with my "success", but I don't think it is the gating issue, but the sum of all the things I have done. I was prepared to twist wires and add snubbers, but I kept those in my back pocket if needed. So far not needed.

Greg

 

[phils2um]

I should mention that I am running with dual protocols, both DCC and mfx. This may have been a contributory factor to issues I've had.

 

[Greg Elmassian]

No, it sounds right as you have described your system, have you isolated your power districts (the feeders create a power district)? And you can do stuff to your lighted cars to avoid that issue, although converting to LEDs would be most likely the same effort and better results.

Greg

 

[Diesel2000]

Hi Diesel2000, (By the way - do you have a christian name you wish to share with us?)

Here are answers to the questions you asked in post 28.

1. My current track plan can be seen in post #64 in the "Phil S' RR" thread in the "Large Scale Pictures" forum.

2. One circuit around the loop is 210 feet. There are currently nine turnouts on the line. 7 are controlled by two 4-channel switch decoders. Two have individual decoders because of their location.

3. The connectors are LGB #50131 Wire Terminals. They're very convenient to keep wire strands together and avoid the need to tin wire ends. Just put one on the wire end and give it a pinch with needle nose pliers to keep it in place. A pack of 50 is about $10 at Only Trains, or Reynauld's.

4. I am using a variety of wire gauges on the line.

The feed from the central station-booster in the house is four conductor 12 awg speaker cable in buried PVC conduit to an external junction box. Only one pair is currently being used. The other pair is for a second booster when I get around to it. I have 12 awg bus wires buried under the track/concrete block coming off a terminal block in the junction box. The bus wire is 2 standard THHN oil and gasoline resistant single conductor wires twisted together with about 6 twists/foot to help reduce DCC signal degradation. There are short LGB 51223 1.5mm^2 cross-section (roughly 16 awg) feeder wires soldered to the bus wires about every 2 meters. These attach to the track at Split-Jaw rail clamps.

Inside the first building in post 27 I used some 18 awg zip-cord (ex-speaker wire) for the sensor connections to the reverse loop module. DCC/power connections to and from the reverse loop module are short segments of LGB 51223 that connect to the terminal block in the building. Most of the rest of the wire is LGB 50140 twin-lead cable (roughly 20 awg) including the DCC/power to the switch decoder and the feeds to the turnout drives.

The switch decoder in the second building is wired with LGB 50140 twin-lead. Note: my longest EPL turnout lead is less than 10 feet. The switch decoder power leads from the track are less than 2 feet in length. The smaller gauge of the LGB 50140 twin-lead is of no concern in this situation.

The turnout lanterns are wired with a combination LGB 50140 twin-lead and some 24 awg hookup wire I had on hand.

The only thing I regret is where I located the external junction box for the DCC power leads from the house. It could have been located elsewhere which would eliminate about 35 feet or more of cable. My overall cable length was causing me all sorts of problems with DCC signal degradation resulting in runaway locos and switch decoders not responding, It is still not completely sorted. It took an oscilloscope to see what was actually happening (terrible ringing on the square wave form). I ended up installing a R-C terminator which greatly improved the signal but robs me of about 400 mA. My DCC signal still gets trashed if too many inductive loads such as incandescent bulbs (older LGB coach lighting) and/or locomotive smoke units are directly powered from the track. Lesson learned - do everything you can from the outset to keep the DCC signal clean. Like Greg said, keep your DCC power leads as short as possible.

sorry for just replying now, it’s been a crazy week from the ECLSTS being cancelled as I was on my way there and work this week trying to sort people out working from home and Local restrictions going on right now.

My name is Tim. I started with O as a child 30+ years ago. My dad had G. He gave some of his trains recently and I decided to finally build a garden layout now that we have the space for it. My daughter loves it so it’s been a great experience so far.

All great info on your layout. I started with the single loop in my first post last fall. I see now I should set up 3 isolated districts on the mainline loop, which will be easy enough to do when I start the expansion with the yard and inner reverse loop. I’m still leaning towards locating the 4 massoth 4 channel switch decoders inside the basement as I plan to use landscape wire under the roadbed gravel during build out, which will be pretty easy to lay during build. My original plan of pvc conduit will be too difficult to route all that and I don’t think necessary. The layout is along the side of the house so none of the runs will be longer than 20 feet.

 

[PhilP]

My only comment would be that unprotected cable, especially in gravel/ballast, will get damaged over-time.

It may be a bit of a pain to drop 'conduit' in from the start, but does make additions/changes easier in the future. - Consider using garden hose, as it can be cheaper, single runs (no joints, gentle bends) and add protection to your wiring.

Lay-in a length of the thin, orange, synthetic 'Builders-Line' to use as a draw-wire (for pulling cables through.. Try to draw all the wires in one go, and make sure you replace the draw-wire, for next-time!
Tie the ends of the draw-wires/lines to a piece of wood (something, anything) which will not pull through. - Nothing worse than losing the end of a draw-wire!

PhilP.

 

[Diesel2000]

Great Advice. I've been trying to plan all morning how it would work. I laid conduit under the mainline for about 30 ft and that was enough for me think twice about wanting to do it again if it can be avoided. The garden hose idea seems a lot easier for ultimately the same effect - wire protection. It would be fairly easy to scoop up the gravel and lay it down under the mainline without causing too much work to replace the pvc conduit and extend it.

Turns out my mainline is 125ft and the addition of the yard and reverse loop will bring it to 290ft. Looks like i should probably add feeders to my mainline (currently only 2, probably need 4). Greg mentioned only having 1 feeder per district so you cant get a signal from more than 1 direction. Dont most smaller gauges advocate having feeders every 3-10ft? Are those all isolated districts from each other?

 

[Greg Elmassian]

There's a lot of misinformation about DCC, and people doing things the same way for 20 years without knowing why.

In the small scales, the "common wisdom" is to not rely on the rail joiners and feed each separate section of rail with a feeder. With much shorter lengths of wire and lower current, and many people twisting their feeders, this is much different from what we do outside.

And the HO guys often use snubbers, and since they are indoors don't have the corrosion and oxidation issues we have.

So, you need to follow best practices for outdoors. Separating the power districts minimizes possible issues that are brought about by the much longer feed lines, which HO does not have.

Hope this is getting through, what is done in HO often has little to do with what we need to do outdoors. If you go back to the electronics and physics of the situations, it all makes sense to an electrical engineer.

Greg

 

[Diesel2000]

There's a lot of misinformation about DCC, and people doing things the same way for 20 years without knowing why.

In the small scales, the "common wisdom" is to not rely on the rail joiners and feed each separate section of rail with a feeder. With much shorter lengths of wire and lower current, and many people twisting their feeders, this is much different from what we do outside.

And the HO guys often use snubbers, and since they are indoors don't have the corrosion and oxidation issues we have.

So, you need to follow best practices for outdoors. Separating the power districts minimizes possible issues that are brought about by the much longer feed lines, which HO does not have.

Hope this is getting through, what is done in HO often has little to do with what we need to do outdoors. If you go back to the electronics and physics of the situations, it all makes sense to an electrical engineer.

Greg

Thanks, yes it makes sense. So much of the info out there on DCC is for HO and smaller, so for someone just getting into it AND trying to build an outdoor layout its a little overwhelming with everything to consider. Given the amount of work it takes you want to get it right the first time so I appreciate all thr hand holding.

It sounds like with a 125ft mainline loop I should make 4 isolated districts with single feeders in each. 30ft sections.

The inner reverse loop is 71ft from the double slip, so that should be powered with 2 feeders, but with a single PSX-AR I should not isolate into 2 districts.

The yard is 95ft total track, but clustered. Will that require multiple feeders or can I get away with just 1?