Hi everyone. Just to warn you all that my 2nd ever question here is no less basic as my first. You guys didn't shred me the first time, so i feel hopeful.
There is so much to learn. In fact my visit to the Basingstoke Model Railway exhibition yesterday, was the first time id actually ever seen a working model railway in my life (and im 49) It was incredible. Such friendly, and helpful people.
My idea of a track layout will include a whopping 2 tracks. The length of track is unknown at this point (not helpful i know) but in my mind it seems to be pretty long spanning possibly 50 - 70 feet of track.
I have 2 of the basic Hornby controllers. One came with my old edition Flying Scotsman kit, and the other i purchased separately when i thought the original was faulty.
I'm not particularly fussed that these tracks will always being separate, but things may change. DCC is my next route. But id rather get the basics sorted before i confuse my addled brain further.
I understand the track is not so conductive the further away from the power unit it is.
So first question, will a different DC power unit\controller help?
I was watching videos about feeder wires. So i watched the people soldering the wires to the tracks, but im not sure where the other end goes (obviously the power :) ) Am i correct in thinking that feeder wires bring the correct amount of power to the track if fitted at correct intervals?
Is there an idiots way of acheiving my goal?
I just want my couple of trains to be able to go round the whole track without conking out.
I'd appreciate any suggestions, and equipment i may need.
Have a great day.
Kind regards
Darren
DDilnottSo i watched the people soldering the wires to the tracks, but im not sure where the other end goes (obviously the power :) ) Am i correct in thinking that feeder wires bring the correct amount of power to the track if fitted at correct intervals?
You are correct. If you think of old fashioned telephone lines, the line from your pole to the house is the feeder. The line between poles is what we call the bus.
The problem is not the DC controller, but the length of the layout, the conductivity of the track and the rail joiner reliability to conduct electricity. You are going to need feeders DC or DCC doesn't matter. If you put in enough feeders, a later conversion to DCC requires no extra wiring.
DCC is especially unhappy with voltage drop off. A feeder every 6' is recommended.
I don't know if wire guage is measured the same on your side of the pond, but over here it would 12 or 14ga for that length bus. 12 ga solid wire is really stiff, go stranded if you go that large.
The quick and dirty way to attach the feeders to the bus is what we call suitcase connecters, really called insulation displacement connectors. Don't go for the Chinese knockoffs if you go that route. They come in specific sizes to match the bus and the feeder. I soldered mine feeders to the bus.
I'd also suggest John Armstrong's Track Planning for Realistic Operation to help planning the track.
Henry
COB Potomac & Northern
Shenandoah Valley
it sounds like you understand that it's not primarily the length of track but the number of locomotives running that dictates the amount of power (current in Amps) that is needed. You also seem to recognize that the voltage will drop the farther from the power source.
Nickle-silve track has more resistance than copper wire. That is wire it is better to wire a bus beneath the layout and attach feeders to the rails every so often (every other rail joint).
The following table quantifies the voltage for 0.5A for various wire gauges and lengths.
---------- Voltage Drop ---------- Amp AWG Ohm/m 10 30 50 70 ft
---------- Voltage Drop ----------
Amp AWG Ohm/m 10 30 50 70 ft
0.50 10 0.003280 0.005 0.015 0.025 0.035 0.50 12 0.005210 0.008 0.024 0.040 0.056 0.50 14 0.008290 0.013 0.038 0.063 0.088 0.50 16 0.013200 0.020 0.060 0.101 0.141
0.50 10 0.003280 0.005 0.015 0.025 0.035
0.50 12 0.005210 0.008 0.024 0.040 0.056
0.50 14 0.008290 0.013 0.038 0.063 0.088
0.50 16 0.013200 0.020 0.060 0.101 0.141
0.50 18 0.021000 0.032 0.096 0.160 0.224 0.50 20 0.033300 0.051 0.152 0.254 0.355 0.50 21 0.042000 0.064 0.192 0.320 0.448 0.50 24 0.084200 0.128 0.385 0.641 0.898
0.50 18 0.021000 0.032 0.096 0.160 0.224
0.50 20 0.033300 0.051 0.152 0.254 0.355
0.50 21 0.042000 0.064 0.192 0.320 0.448
0.50 24 0.084200 0.128 0.385 0.641 0.898
The voltage drop depends on current and will be highest when current is highest presumably under higher load when you need the most power.
Wire gauge gets smaller as the wire gauge # increases. 24 gauge wire will have a voltage drop of 0.9 V at 70 ft for 0.5A, or almost 2V when considering both wires. 10g wire will have less than a 0.1V drop.
I think a 2% drop is accepatble. 0.24V for 12V. 16g wire would have a drop of 0.28 over 70ft at 0.5A. 18g would have less.
greg - Philadelphia & Reading / Reading
gregc ... 16g wire would have a drop of 0.28 over 70ft at 0.5A. 18g would have less.
... 16g wire would have a drop of 0.28 over 70ft at 0.5A. 18g would have less.
Perhaps I misunderstand, Greg, but the higher the gauge number for wire, the thinner it is, and the greater (not lesser) the resistance and voltage drop. So, 18 gauge wire has more resistance and would have more voltage drop over any given distance.
I relied on a table in the Kalmbach DCC Guide (version 1) and related comments. It suggests bus wire gauge for several (wire) run lengths, including for 2A and 5A DCC systems ratings. The table is based on limiting voltage drop to 1/2v. (For my HO gauge, I planned a 5A DCC layout, which will handle many typical HO locos at roughly 0.5 - 0.75A max each.)
For a 2A system, the table includes max lengths of 39' for 18AWG bus wire, 62' for 16AWG, 99' for 14AWG, 157' for 12AWG.
For a 5A system, the table includes 16' for 18AWG, 25' for 16AWG, 40' for 14AWG, 63' for 12AWG, 100' for 10AWG.
Recognize that the DCC system's location (where the outgoing bus connects) as well as the bus configurations influence greatly the max length of any bus. If your runs were 70' straight, you would have a 70' run if the DCC system is at one end. But if the system were located in the middle, you could have two ~35' buses (from a Tee) going out in each direction. Similarly, if your 70' run is a circle or loop, you can have your power source somewhere near the loop and run two 35' buses out from there in opposite directions (do not connect the far ends to each other).
If in HO or OO scale, folks have already recommended feeders at 6' intervals. The DCC guide recommends 20 - 22AWG feeders. I kept mine to 18 - 24" max. In my case, I had no bus over 20' long, so used just 16AWG stranded wire bus and 22AWG solid feeders, connecting with 3M suitcase (IDC) connectors for joining those sizes.
I soldered most of my rail joints, so connecting at 6' intervals took care of two pieces of joined 3' HO flex track. Where a short piece of unsoldered track or a (typically) unsoldered turnout was installed (only friction held by rail joiners) I added extra feeders to each piece of track (jumpers within my turnouts connected lots of the turnout rail pieces that stay in mutual polarity).
Do reply with whether your 70' is straight point to point, or a 70' circumference circle or loop, plus where your DC/DCC system will be located, and we can be more specific. But if planning for DCC, do wire things that way from the start. Not that much extra trouble.
Paul
Modeling HO with a transition era UP bent
selector gregc ... 16g wire would have a drop of 0.28 over 70ft at 0.5A. 18g would have less. Perhaps I misunderstand, Greg, but the higher the gauge number for wire, the thinner it is, and the greater (not lesser) the resistance and voltage drop. So, 18 gauge wire has more resistance and would have more voltage drop over any given distance.
thanks for catching my mistake. 18g would have a higher voltage drop.
Thank you all so much for your help. I must to confess to not undertsanding much, about the electrical side.
The setup is 00 gauge, and the single track will be a large loop. One of you guys recommended a book that might help, and i ended up buying the one mentioned, and five others from Ebay.
I watched a few more videos on Youtube, and now understand the buss wire, and the dropper wire.
The guy in one of my videos showed one end of the pair of buss wires not terminating to anything. Its the power source im not sure about. On my hornby controller are the two wires that connect to the track. Would this be what the buss wires attach to?
Would the basic Hornby controller be enough, or would a separate power supply be recommended?
## Last night i actually purchased a Hornby HM2000 power controller as that seems to be pretty good for my needs. It has slots in the back to attach the power cable.
So i want to thank you guys again, for taking your valuable time, and expertise to aid an old newbie.
You will be well served to look over the books and/or websites carefully to get a basic understanding of DC wiring before hooking anything up. Perhaps you have a hobby shop or model RR club you can visit for assistance also. There is a learning curve involved.
DDilnottThe guy in one of my videos showed one end of the pair of buss wires not terminating to anything. Its the power source im not sure about. On my hornby controller are the two wires that connect to the track. Would this be what the buss wires attach to?
Each side of your Hornby dual controller has adjustable DC output for your track, which allows adjusting the voltage to change loco speed, with the reversing switch simply flipping the DC output polarity to change the loco direction. Thus, the two output wires could be connected to the two track rails in just one spot in a small loop.
But for a larger loop, you will simply extend the pair of wires as a "bus" pair, adding smaller feeder wire pairs about every 6' as you go. (You must keep the connections from a given wire to the same rail as you go). The bus wires are simply extended controller output wires to the track (via smaller feeder wires).
When you get to the last pair of feeder wires added, typically you will have connected them to near the ends of the two larger bus wires; i.e, the bus wires themselves will each have a dead end extended. If done that way, you need to cap off each one (with a wire nut or tape) to prevent them from touching anything. If you connected them to each other you would SHORT your controller output, a bad thing!
An alternate approach would be to solder your last feeder wires to the ends of the larger bus wires, and add insulating electrical tape at the soldered joint. That way you would not have a dead end of each bus wire needing to be capped off.
For those interested, the Hornby dual controller HM2000 (R8012) instruction sheet can be opened from this listing. Each of the dual DC track outputs is rated for 550 milliamp (0.55 amp):
https://www.hornby.com/uk-en/downloads/view/index/cat/14/
If you're planning to go the DCC route eventually, feeders and a bus wire might be a good idea. My layout is strictly DC, and while I couldn't tell you how much track I have in total, one trip around the room (not a usual operation unless my grandkids want to run trains) is just over 140'. The layout, however, is normally operated point-to-point, with several possible end points, most between 120' and 150' in length. While I normally run only one train at a time, it may have several locomotives due to the many grades and curves. All of my rail joiners are soldered in place, except those at the ends of bridges, as I like to have the bridges removeable for easy layout cleaning.Power is from an MRC Controlmaster 20, through a Stapelton PWM walk-around throttle.This is the power connection to the tracks...
I have never experienced any noticeable power drop anywhere on the layout, and as mentioned most trains use multiple locomotives because the trains themselves are heavy.When the grandkids are running trains, it's usually locomotives only, often more than a dozen chasing one another around the layout, so I don't buy the premise that rail is a poor conductor, at least not in my practical experience. DCC is apparently a little more fussy, and since I don't use it, probably should leave it at that.
Wayne