Why Buy When You Can Make Your Own Detector Wheelsets (319)

Nothing is as satisfying as making your own components for your model railroad and then showing them off to your friends. So why not make up a batch of detector (or resistor) wheelsets instead of buying them from DCC Concepts or LogicRail? In this video I'll show you how easy it can be to do just that!
You can find the conductive glue at Allelectronics.com. The company that makes it has a website for it at www.wireglue.us
I got my 10K 1/8W 0805 resistors from Ngineering.com but you can also find them and 10K 1/4W 1206 resistors on eBay.
Chapters
0:00 Intro
0:40 Parts, tools, and supplies
3:40 Checking for insulated wheel
4:40 Preparing axles and wheels
6:00 Gluing on the resistor
7:15 Applying conductive glue
8:00 Testing the final resistance
8:35 Wrapup

[@TheDCCGuy]

In case you are searching for it All Electronics now lists “Wire Glue” as “Conductive Glue”.

[@randydobson1863]

hello larry its is randy and i like yours is cool thanks friends randy

[@gregorykeliher542]

Informative and practical tip Larry. The reading of the resistor after installation could also be due to the tolerance of the resistor value which is about 10%. Keep up the great videos they are extremely helpful reference and instructional tools for the hobby.

[@TheDCCGuy]

Good suggestion. It did settle in at about 11K as did several others I did which really is close enough given the tolerances.

[@thomasgrassi8817]

Larry I tired this method a long time ago and them did not work out well for me, After watching this video I think I will give it another try My railroad rule is all cars have resister wheels and been purchasing them I would like to make them again back then I was new to this and feel confident now that I can do this Have a nice holiday weekend.

[@TheDCCGuy]

I have also seen methods that recommend using conductive paint and Streamlined Backshop sells resistive paint which you can use instead of a resistor. That way you can just paint a line on the axle to create your own resistor!

[@derekalexander4030]

Larry, any idea what the resistance is using the paint?

[@TheDCCGuy]

@@derekalexander4030 No but if you go to the Streamlined Backshop website he has a description there of the process. As you might expect it is an iterative process-paint a line, measure, scrape a little off, measure again, etc.

[@frankneher9192]

You probably should have mentioned check the gauge of the wheelset after sanding and before glueing on the resistor.

[@TheDCCGuy]

Good point!

[@randysrockandrollrailroad8207]

🤠

[@brucefogwell5828]

Just to be clear, if you are working on a freight car with two trucks each having two axles: • For each truck, do you need to put a resistor on both axles or only one? - If both, does it matter whether or not the insulated wheel for each axle is on the same side as the other axle? In other words, should they be on the same as for the other axle? • Do you need to have a resistor(s) on both trucks or is having it on only one truck sufficient? - If you need to have a resistor(s) on both trucks, do the insulated wheels of each truck need to be on the same side as the insulated wheels on the other truck?

[@TheDCCGuy]

The axle orientation doesn’t matter since you are bridging the insulation with the resistor. I usually put two resistor wheelsets on each car instead of two on each truck. I do this to spread out the detection and avoid dirty spots on the track. I also don’t put them on every car, just enough to have a few in each train. At a minimum I want to have a detector equipped caboose or passenger car on the end of each train.

[@brucefogwell5828]

@@TheDCCGuy Thanks for your response. One other question: you refer to 10K 1/8W 0805 resistors and 10K 1/4W 1206 resistors. Another N-scale site uses “603” resistors (I assume 10K?). How would you know which of the three resistor types to use?

[@brucefogwell5828]

For N-scale.

[@TheDCCGuy]

You first need to decide which detectors you will use and find out their requirements then proceed with the installations.

[@brucefogwell5828]

@@TheDCCGuy Thanks

[@jayfuller3709]

Great video!!! Thank you. All Electronics no longer carries the Wire Glue. Any suggestions as to where we can get it????

[@TheDCCGuy]

I checked yesterday and they still,had it listed. As I wrote i the description look for conductive glue.

[@jayfuller3709]

@@TheDCCGuy I tried that & it was found. So I ordered it! Thank you!!

[@HumancityJunction]

Thanks for this demonstration. I bought all the pieces and parts, but I have not attempted to make them yet. Any idea if they give issues with frog juicers?

[@TheDCCGuy]

Frog juicers are more of a problem in their own with detection since they use a small amount of current and may be detected by the block occupancy detector themselves. Most detectors have a way to decrease their sensitivity to address this issue. For example the BD-20 has a spot for attaching a resistor that will reduce sensitivity and some DCC Specialties products have an automatic procedure that calibrates it to empty rack and corrects for any “background” current drain.

[@HumancityJunction]

@@TheDCCGuy Thanks for the detailed answer!!

[@stephensouthcombe6439]

Does this affect axle balances to any noticeable amount? (i.e. - do faster running trains vibrate, etc.)

[@TheDCCGuy]

Not that I have noticed and model railroaders have been using them for decades.

[@LeonKolenda]

I have a question. As a beginner, what the H__ are these for, and why do you need them, and what happens if you don't have them, and do all rolling stock cars have them?

[@TheDCCGuy]

I provided links to 2 videos that go into this, so please take the time to at least watch them.

[@TrainmasterSweden]

These are used if you have electronic block detection to see if something is on a specific track. This is for example used to control signals or other stuff, and also if you use computers to control the layout. Locos and all cars that draw power from the track (for example cars with interior light) are already detected by their power consumption. Cars without any functions are electronicaly invisible because of the isolation between the wheels. You could call this a "virtual power consumption" add-on to these cars, to make them electronically visible. 🙂

[@roundhouses]

I did very much the same method on my British N scale layout some years ago so that the signals could be controlled via the block detection. I hadn't thought of using tweezers to hold each wheelset. I used a piece of packing foam with small slots cut into it to hold a few wheelsets at a time. I also put a white line on the truck next to where the resistor fitted wheelset is so I can quickly identifiy them. As my Amerian N scale cars had Microtrains plastic wheelsets, I used the ready fitted Fox Valley ones but as they were hard to get over here in the UK I have only fitted a few cars with them.

[@TheDCCGuy]

I am mainly interested in detecting the presence of the train so as long as the loco or caboose or a lighted passenger car can be detected that should be enough.

[@TrainmasterSweden]

Great vid, I have done a few cars like this myself! 👍 Still, my question would be why you chose 10K? Sure it works great, but some use 20K and other values as well, and I have yet to find out where these figures come from and how they might affect the system depending on type of trains, length etc. On a long block with many cars, I guess there could be a significant power draw?

[@lgrfbs]

Each resistor will be connected in parallel. So let's assume that only one resistor is in the sensing zone then it will appear as 10K, if two resistors are in the same zone the result will be 5K. Parallel = divides the resistor. Serial = adds the resistance.

[@TrainmasterSweden]

@@lgrfbs Yes, I'm aware of that, and this is exactly why I ask. Too high resistance would obviously never cause a problem except for not being detected, but low resistance results in more power transfer between the rails. (Zero resistance = shortcut). So what effect could it have with let's say ~100 cars with this on the layout, or let's say ~20 in a block? I haven't done these measurements myself (yet).

[@lgrfbs]

@@TrainmasterSweden Interesting, don't have enough electronics maths to answer that. I appreciate your videos.

[@TrainmasterSweden]

@@lgrfbs Thanks. Yes, it's interesting and that's why I wonder why 10K (or any other value). I'm about to do some calculations on it, so the following is just speculations from my side: 🙂I guess it depends a lot of your equipment as well, not just detectors but also shortcut breakers etc. Likely you won't notice anything at all on a small layout, but with a larger layout maybe you should try with the highest resistance that could be detected on your equipment. But as said... just speculation as of now.

[@TheDCCGuy]

You need to use what the maker of the detector recommends. Some are designed for 5K some for 10K, etc. I have asked my EE technical advisors to wade in on the issue of how detection works when multiple resistor wheelsets appear in the same block and hope to hear in a day or two.

[@derekalexander4030]

Thanks for doing this Larry. So this small amount of resistance can be detected by a Digitrax block occupancy detector? Also, if you had a train with 25 cars and you did this on each wheel set ( 2 of the 4 on each car ) on each car and all of the cars were in the same block, how much power would they draw? I know if you have a loco with lights and sound and a lighted caboose it would be higher but what would it draw just for the 25 cars with the detector wheel sets?

[@TheDCCGuy]

I don’t remember what resistance Digitrax recommends for use with their detectors. I have asked my EE technical advisors to wade i with an answer on the issue of how this works with multiple resistor wheelsets in the same block and expect an answer this week.

[@derekalexander4030]

@@TheDCCGuy Thank you Larry, I appreciate you doing the video, responding to my question, and seeking expert help to answer the question. I would also like to find out how much power a train of that length would draw so I would be able to determine how many amps I would need for each train of that size in a block.

[@frankhellman6879]

@@derekalexander4030 Mr. Derek! We are far from our usual haunt today! I gather you’ve got or will have independent “blocks” for signaling and power. I’ve no plans to do this, but do have some ideas from others and my own. Get a beer… 1) The biggest issue is that different detectors have different detection minimums, even the same make & model. If the manufacturer or someone lists a minimum current (Google is your friend!) at the working voltage of 12-15V, make sure each resistor wheelset passes at least 10% over the minimum amps to ensure detection. Then test each set individually on a spare track hooked up to a detector before putting it back on the rolling stock. Each truck (one resistor wheelset) should set off the detector. A multimeter will work if you haven’t bought a detector. If you can’t get the minimum, use a ~12V power supply (a command station will work), a 30k, 20k, 15k, 10k, then 7.5k cheap regular resistors, with the detector in series. Gradually reduce the resistance until the detector reacts. Then use that resistance or the next lower in micro resistors. 2) You only need one resistor wheelset per truck and it best be the wheelset closest to the coupler if you have truck couplers - doesn’t matter with car mounted couplers since trucks spin like tops. For better accuracy, use another resistor wheelset on the other car truck. Since resistors in parallel cut the overall resistance, two 10k wheelsets, one on each truck with clean wheels will have the equivalent resistance of 5k total. That’s half the resistance of one 10k wheelset. Half the resistance, more current passes, better detection. BUT, too many resistor sets in a block may trip the command station breaker or overheat it and the locos. Thus: 3) It’s best not to put 2 resistor wheelsets on each car you own. You only need either a locomotive powered on at one end, and one car with resistor wheelsets at the other end - presuming your train is shorter than the shortest block it goes through. If the train will be longer, you need one resistor car in the middle somewhere, too. So, the thing is to only use these wheelsets on cars that need them. If you’re just running circles, then the lead loco, one car in the middle and one at the end in a train that’s between 1 & 2 blocks long will fully detect. In fact, a 2 block long train with mid-train distributed power & rear-end power (all consisted & running) doesn’t need any resistor cars - unless you turn the engines off. For caboose era layouts, putting 2 resistor wheelsets on every caboose may cover 90% of mainline & modeled branchline trains (i.e., not fake interchanges). As long as there’s one powered on loco or resistor wheelset in every block, whole trains will fully detect. If you want to do operations, especially in the post-caboose era, it gets more complicated. In simple terms, you want to yard-classify every outgoing mainline and modeled branchline train such that you’ll set out each group of cars so the one resistor car in each group will be the furthest back in each group of the pick up train(s). This way, no matter who picks them up, in what order or when, a resistor car will be the rear car. Real or dummy flasher if you can work that out. - If you plan to leave a set of cars on any main/main branch line track that will straddle 2 blocks, then yard-classify for the front-most car to be left on the main to have resistor sets. - If you use modern era rear-end flashers, then each car with a built in one should have at least one resistor wheelset closest to the flasher end, preferably not on the flasher’s electrical pick-up set if it flashes too. - Every MOW unit, rear platform passenger unit, unpowered dummy B units, slugs & tenders, a couple decrepit push cars locos, and other ad hocs should also get the treatment. - Put sets on one or two of all remaining types of generic-use rolling stock you have, just in case. (cattle, tank, box, flat, hopper, etc.) You can signal big yards & major multi-industrial sidings, but that starts getting very complicated to plan. Good luck Derek!

[@derekalexander4030]

@@frankhellman6879 Wow, thank you Frank. What I wanted to accomplish was to have each car detected so that any car left on the main or any other track or siding while switching would be detected and the signal system would protect the track. I’m planning to use Digitrax Command control and I want to run the transition era, specifically 1953 UP, SP and ATSF, with cabooses, but didn’t want to just use the loco, caboose and one car in the middle to set off the signals in case the car in the middle was placed in a siding or yard lead and the rest of the cars sitting on the main or siding then wouldn’t be detected. My other concern was how much power would the 25 detected cars draw in a block and would I need to increase the amperage because of them. Nothing is in stone and I’m listening and appreciate your experience.

[@frankhellman6879]

@@derekalexander4030 You're welcome, Derek. In the history of RR signaling, mains & branch line mains have been signaled by block, at interchanges, major yards, major traffic sidings, RR-RR crossings (diamonds, X-crossings) and passing sidings. But minor sidings are almost never signaled, they use derails. Modern small derails are mostly post-1950s. Before those, typical small & medium sidings were protected by catch points on the siding near the mainline. Before that time, a siding full turnout near the mainline that just led to dirt & gravel. The catch point is typical in the 50s & 60s. It was a single shortened turnout point rail that flexed at the point end, just like real turnouts. If mounted just inside one rail & flexed inward toward the track center, cars pass through. If released by what’s essentially a manual turnout throw, it slammed against one of the siding’s rails, causing an errant car coming out of the siding to derail short of the main, say if the car’s brakes failed. They’re still used in places. Small industry sidings in the 50s would either have catch points, some homemade derail, or nothing (there were still many rail accidents and RR workers killed in the transition era; 2500-3000 annually). These sidings simply didn’t get signaled unless they were a major traffic spur, very urban, or there had been many accidents. Signaling small spurs just isn’t historically done (railroads were cheap with safety). The conductor, who was in the engine, would jump off and release the catch point after entering the siding, then later set it for the engine alone to back out to the main, and release it again to protect the main from runaways on the siding. Even today that's normal, just mostly it's those yellow portable derails (check DJTrains' operations drone videos of industrial sidings. Even big industry sidings are only protected by a 2-foot piece of cast metal on one rail). Most yards of the 50s with 3-6 classification tracks and one A/D track (typical HO layout) would not be signaled either, except at the main(s). Back then labor was cheap - cheaper than installing even dwarfs with all the wiring, maintenance & electricity costs. People switched and directed trains under the yardmaster & district dispatcher back then. Today, engine conductors or yard workers switch & direct in yards. There haven't been signals in many small-medium yards since the early 40s. One way to cut the number of resistor wheelsets would be to use only one per car. Still, just 10 cars in one block using 10,000 ohm resistors would be equivalent to a single 1k resistor. The DCC station might not trip, but it would warm up, the engine would warm up and maybe the lights would dim slightly, but that’s not the problem. The decoder(s) in that block would probably stop working well and a decoder BBQ is possible. Your whopping 25 cars would be merely one 0.4k resistor or 400 ohms, 4% of a 10,000 ohm resistor🔥. So be careful.