AI-generated illustration, not a photograph of a specific product
"My train slows down at the far side of the layout — do I need more feeders?" It is one of the most common questions once a layout grows past a starter oval, and the internet answers it with confident numbers: a feeder every three feet, every six feet, every so many rail joints. Before you cut a single wire, here is the part those answers skip: most poor running is dirt and loose joiners, not a shortage of power.
Five words worth pinning down first
| Term | What it does | Common misreading |
|---|---|---|
| Feeder | Carries the controller's output into the two rails | It is not a controller and it does not add current |
| Controller / power pack | Supplies and varies voltage and direction | Its current rating is not "a maximum number of trains" |
| Continuous section | Track that is still electrically joined together | Looking separate is not the same as being isolated |
| Gap / insulated joiner | Electrically separates one section from another | Gapping one rail only is not isolation |
| Polarity | Which rail is which — on DC it sets direction | A feeder wired backwards is a short circuit |
Our position: nine times out of ten it is dirt, not power
This is the most useful sentence in the article: the overwhelming majority of "runs badly, slows at the far end, stops and starts" complaints come from a dirty railhead, dirty wheels or a loose joint — not from insufficient supply. Yet the first instinct is almost always "add a feeder", and people end up with wire everywhere and the same fault, because nothing they did addressed the cause.
So the advice is blunt: when running goes bad, clean and inspect before you wire. Clean the railhead and the wheels (see the cleaning and maintenance guide), re-seat every rail joiner, and confirm the feeder plug is fully home. Those three steps solve most cases and are free. Adding wire belongs at the end of that list, not the start — treat it as a last resort and you will save yourself a lot of pointless work.
Slow at the far end: a five-step diagnosis
1. Fix your test conditions
Use one locomotive whose behavior you know, the same throttle setting, the same direction and the same load. Without that, comparing two locations tells you nothing.
2. Clean
Clean the railhead and the wheels. Poor contact concentrates where trains habitually stop and where the track is awkward to reach — which is not evidence that the run is too long.
3. Check the joints
Work along the track confirming rail joiners, plugs, feeders and turnout settings. A joint that has been taken apart and reassembled a few times matters far more than total distance.
4. Check load and shorts
Take off the interior lighting and the other trains. Watch whether the controller's protection trips, and look for a derailed wheel bridging the rails. Several powered units plus a fully lit rake on one controller adds up.
5. Only now add a same-source feeder
With the first four ruled out, power down and add one feeder from the same controller with the same polarity, using the manufacturer's own distribution parts and following their instructions. Power up and compare against your earlier test. Write down the locomotive, the controller, the track plan and the date — one success is a data point, not a formula.
What KATO and TOMIX actually sell for this
Both makers offer parts for getting one controller's output to several places, and it is worth being clear that all of them distribute, they do not amplify:
- KATO: feeder track, the Terminal UniJoiner, extension cords and a three-way splitter. The splitter divides a single output between several points; the total load is still capped by the controller's rating. See KATO's wiring accessories page.
- TOMIX: the 5534 D.C. Feeder N, and the 5812 branch cable that splits one Power Unit's output to additional feeders. The 5812 is not a second controller and cannot give two trains independent speed control.
A dead siding is often a turnout working correctly
If a spur or a passing loop has no power, do not assume a fault. It is very likely the turnout's power routing behaving exactly as designed: current goes only to the route the points are set for, and the unselected road goes dead — which is a convenient free parking spot. Forcing a feeder past the turnout to energize that road destroys the very feature you were given. The right sequence is:
- Look up the power-routing behavior of that exact part number — the KATO #4 can be switched, the #6 cannot; see the turnout guide.
- Decide what you actually want from that road: dead when the points are against it, or always live.
- Then, following the manufacturer's wiring diagram, decide whether it needs a feeder, a switch, or its own isolated section.
Double track, and when you genuinely need two controllers
| What you want | Control outputs | What it requires |
|---|---|---|
| Both lines obey one throttle | One controller split to both | Total load within rating, matched polarity |
| Two trains running independently | Two separate outputs | Electrically isolated sections |
| A crossover so trains can change lines | Per the full system design | Gaps, turnouts and crossing procedure per the maker's diagram |
Measuring it yourself, safely
If you want to know what the voltage actually is at the far end, a multimeter will tell you. A few lines not to cross:
- Use the voltage range and measure DC between the two rails. Keep the load identical at both ends or the comparison is meaningless.
- One probe per rail. Do not let a single probe tip bridge both rails, and do not let the two tips touch each other.
- Leads belong in the COM and V/Ω sockets. Never leave a lead in the current socket and then touch it across both rails — that is a deliberate short circuit through your meter, and it can destroy the meter and damage the controller.
- With no manufacturer's threshold to work from, do not invent one. "More than X volts of drop is a failure" is a number you made up.
- If the controller's protection trips, power down and look for a derailment, reversed polarity, a short or an overload before doing anything else.
If your layout is a tabletop oval, none of this is your problem
Here is the reassuring part. A desk-sized layout — an oval, maybe a siding — will almost certainly run on a single feeder, and no amount of wiring diagram study will improve it. Serious power planning and district design belongs to wall-length layouts running several trains on double track. That is a real discipline, and it is not yours yet.
So do not be intimidated by the elaborate bus diagrams you find online. Those exist because of their scale, not yours. Get one oval running well — clean track and one feeder — and expand the wiring when the layout expands. It is worth marking intended feeder positions on the plan while you are still drawing it; the track planner is a good place to do that. If running is still unreliable after the five steps above, work through the troubleshooting guide. And if you are building modules rather than a fixed layout, note that module wiring and layout wiring are separate problems — see the T-TRAK guide.
Sources
Last checked 2026-08-01. Feeder parts, turnout power routing and double-track isolation follow KATO's and TOMIX's own product pages and FAQs. For any specific turnout or controller, the instruction sheet for that exact part number takes precedence over any article, including this one.
- KATO Unitrack wiring accessories — feeder track, Terminal UniJoiner, splitters
- TOMIX 5534 D.C. Feeder N and TOMIX 5812 branch cable
Running badly? Clean it before you wire it
Feeders and wiring: common questions
How many feet apart should N scale feeders be?
There is no universal spacing rule, and neither KATO nor TOMIX publishes one. What actually matters is the number of rail joints, how many turnouts are in the path, whether sections are isolated, the total load and what you measure. Most small layouts run perfectly on a single feeder. Do not apply an invented rule like one every three feet — if the far end really is slow, clean the track and check the joiners first, and only add wire if that fails.
Why does my train slow down far from the feeder?
Distance is rarely the real cause. Far more often it is dirt on the railhead or the wheels, a loose rail joiner, a feeder plug not pushed fully home, an overloaded controller, or a power-routing turnout doing exactly what it was designed to do. Until those are ruled out, blaming the length of the run is guesswork — the large majority of poor running is contact, not supply.
Will adding feeders make my train run faster?
No. An extra feeder can only recover supply that was being lost to poor contact or resistance in the path. It does not raise the controller's maximum output, and it will not fix dirty rail, a short circuit or an overload. Top speed is a function of the controller and the locomotive, not of how much wire you have run.
Does a three-way splitter or branch cable add current?
No. It distributes one controller's output to several places. The total load is still limited by that controller's rating. Distribution is not generation — you can add as many connection points as you like and no additional current appears.
Does double track need two controllers?
Only if you want the two trains to run independently. Independent speed, direction and stopping requires two separate outputs and electrically isolated sections. Share one controller between both lines and both lines obey the same knob and the same direction switch, though the actual speeds will differ a little with the condition of each locomotive.
Can I connect two controllers to the same section?
Not without electrical isolation — never. Two outputs fighting each other across the same rails can short and can damage equipment. If you want separate control, first gap the sections with insulated joiners so each controller owns its own section, and confirm the isolation before powering up.
Why is my siding dead?
Most likely the turnout's power routing is working correctly. A power-routing turnout feeds only the route the points are set for and lets the unselected road go dead. That is a design feature, not a fault — it gives you a free place to park a train. Forcing a feeder past the turnout to wake that road up removes the parking function you were given.
What is the single most important rule when adding feeders?
Every feeder on one continuous section must come from the same controller with the same polarity on both rails. Reverse one and you have wired a short circuit. If the protection trips the moment you power up, or a wire gets warm, cut the power and investigate — do not keep resetting and trying again.
