How to wire your track for DCC "Block detection" using the NCE-BD20.

If you are planning your layout or thinking of adding signals , you will need some way of detecting rolling stock on your rails! The NCE "BD20" is a versatile and economic way of detecting rolling stock and sending that information to your interlocking of choice! This video shows how they work and how to wire your layout for easy installation when you decide to add signalling!

[@mikesimmons8762]

5-2023. Greg. Shout out came from Chadwick Model Railway #121. Your video was informative and fun to watch.

[@neilschwerdt3493]

Hi buddy I hope you have a great week. I'm going to start wiring the system for the third time now. I hope I get it right this time . I'm getting trred of doing wireing again. I do not like to do wiring at all.but I know if I don't the system won't run at all. Thank you Gregg for your help I love your voids you make on KZbin. I hope you have a great week. From Neil schwerdt in west valley city Utah

[@SilverCreekSub]

We are just about to start CTC on our layout and this was extremely helpful!! Thank you so very much for making this video

[@FishplateFilms]

Thank you and my pleasure! As a signal , I know how much work goes into signalling a layout! I work on the real stuff everyday, so I'm on no hurry to have it at home..LOL Though it's very cool to see working in minature. Cheers Gregg.

[@nssherwoodsub]

Greg...in 21 minutes you provided an explanation superior to what I would have learned in hours by reading the detector's manual. Thanks very much. Maybe I'll give this a try on my layout.

[@FishplateFilms]

Thank you and you're welcome! Signalling a layout is not a small feat but you can do a section at a time or as much as you want. Appreciate the support. Cheers Gregg.

[@neilschwerdt3493]

Good Morning Gregg I hope you have a great weekend and thank you for your help when I watch you on KZbin. From Neil

[@FishplateFilms]

Thanks Neil! I've been on nights so a lot of sleeping. Glad you get some tips from the videos. Gregg.

[@leegilbert9130]

I have only comment to make HELP just started my first simple layout, but I will seek advice from my club members, all your video's are very informative Regards

[@FishplateFilms]

LOL...DOn't panic Lee...this is advanced stuff in this video and is for signalling purposes, so you don't have to worry about it! DCC is far easier than DC and much more fun! Just two wires and make sure you keep the tracks the same polarity round the layout. I'm sure your club will help you out and thanks for watching! Cheers Gregg.

[@154Colin]

Good to see that you're more active on further construction of your layout. You have, and are, giving a good amount of effort and time to see that it performs to the standards that you feel it needs.

[@FishplateFilms]

Thanks Colin! I get slack at times and shift work at my age is starting to take it's toll! I have been busy on the house but nearly done on that so hope to do more on the layout in the future. I guess working on the real thing makes you less keen to do it at home..LOL . Sometimes it's fun just to run a train! Cheers Gregg.

[@roysnelgar1820]

Thanks Gregg, this trendsetter now has an understanding of how block detection with DCC works. thank you for the explanation class room style. Cheers cobber.

[@FishplateFilms]

You're welcome Roy! Glad to be of service. Cheers Gregg.

[@jameswolf195]

BEST explanation I have seen on the proper way to set up block detection on an HO layout. Thank you.

[@FishplateFilms]

Thanks James! Glad you liked the video and got some tips from it. Cheers Gregg.

[@tombrennan9452]

There are so many videos on youtube about model railways! And I love seeing American layouts in action. But its nice to hear a familiar accent going along with it! Aussie Aussie Aussie!!!

[@FishplateFilms]

Thats true Tom. I watch so many US and Canadian videos that the Aussie accent catches me out too! Thanks for watching. Cheers Gregg.

[@johngreene8635]

Gregg, this was very beneficial to me as it clearly illustrated my need for G scale CDCC layout. Computer control is my next step up in DCC and appreciates the electric circuit lecture with the BD20! Thank you mate!

[@FishplateFilms]

Thank you John and you're welcome! Good luck with the next step on your layout! Cheers Gregg.

[@hythesailor]

Brilliant video! The only one I have watched which makes sense of how to wire a block signalling setup. Cheers!

[@FishplateFilms]

Thanks very much Matthew! I'm glad it worked for you and I appreciate the kind words. Gregg.

[@ScottDowneywoundedbear]

Very helpful information. Need to learn all I can before trying to rewire the layout.

[@FishplateFilms]

Thanks Scott! At least if you do the basic wiring at the start , it will be a lot easier if you decide to put some signals in! Cheers Gregg.

[@georgef.7434]

Excellent explanation, for what could be rather confusing for most.

[@FishplateFilms]

Thank you Big G! I do find it confusing..LOL Cheers Gregg.

[@joesaurina1402]

Well done Greg, learned more in 20 minutes than from all the crap I've read on the BD-20's. Cheers

[@FishplateFilms]

Thanks Joe! There is a lot of theory behind it all...too much for me..LOL. Glad you enjoyed it. Cheers Gregg

[@sparky107107]

wow,, that's a lot of info in a short amount of time. I am not there yet for my layout,, but nice to know where to find this info,, in a easier way to understand it. love the shirt, with reflective strips

[@FishplateFilms]

Thanks Sparky! I tried to make it short but you know me..LOL It's actually pretty cool that we can do this!! The shirt is part of our uniform and is very good at night when working on track! Cheers Gregg.

[@BNRailNut]

Not Boring at all Trend Setter , It was very informative one aspect of the Hobby we need to Know - especially when at the points.....Cheers-Rich.....

[@FishplateFilms]

Thanks Rich! The hobby these days is getting a lot more complicated...and more expensive! Glad you enjoyed it. Cheers Gregg.

[@georgeblair8742]

Another excellent instruction video from Down Under Gregg

[@FishplateFilms]

LOL..Thanks George, glad you like the ranting's!! Cheers Gregg.

[@dannyholt105]

Nice tutorial Gregg! I had no idea how block detection worked before. I thought IR was the only way to go. I was scratching my head though trying to figure out how it might work because of the metal wheels being insulated. I saw in your response to another question though about using 10-15K ohm resisters. That was my AH!!! moment. LOL! Thanks for the lesson. Cheers, Dan

[@FishplateFilms]

Thanks Dan! I used IR on my early layout and it is a pain, but the only thing we had up till a few years ago! You can get away with just the locos for starters but you'll need the cars done to make it work properly. Glad you got something from it. Gregg:-)

[@Tcostello105]

Excellent video thank you for the information on DCC and block detection.

[@FishplateFilms]

Thank you ! Glad you got something from it. Cheers Gregg.

[@DGModelworks]

Whew!!!! You made my brain hurt. HAHAHA. Great video Gregg, and you certainly broke it down in terms that are understandable. Thank you for taking the time to explain it so thoroughly. ~Deryk

[@FishplateFilms]

My brain always hurts Deryk! Not quite as complicated as the stuff I work on but not too far off in some cases! It certainly is a whole other level of the hobby. Glad you liked it and thanks for having a look! Cheers Gregg.

[@wolfpack4694]

Well done sir! Thank you for helping me understand it better!

[@FishplateFilms]

Thanks John! Glad you got something from the video! Cheers Gregg.

[@mstanco3153]

Best that England has to offer your videos are fantastic and God save the queen!! ps hope i get to visit Australia some day.....MIKE

[@FishplateFilms]

LOL...thanks Mike! Come on down when you get the chance. Gregg.

[@neilrogers1571]

That's good advise food for thought I am a little way off purchasing the first ones just trying to see what others are doing, I plan on going to a specialist supplier here in old Blighty to discuss this I understand he is one of the team involved with JMRI so think he will a good person to speak to.

[@FishplateFilms]

Yes Neil, the boys in JMRI are smart cookies! You'll get good advice from them . I like to keep things simple and easy for fault finding. Cheers Gregg

[@samhane11]

I love your Video, Very educational. laid back. Yet serious. Thank You so Much . Love your accent. Gooday mate. Keep your videos coming. Samhane11 USA

[@FishplateFilms]

Thank you very much Sahame. Glad you enjoy them and get some info at the same time! G'Day and cheers from Down Under. Gregg.

[@chazco]

Great video, Thanks Chuck

[@FishplateFilms]

Thanks Chuck! Gregg :-)

[@neilschwerdt3493]

It me again Neil schwerdt I'm doing the MRL and BNSF on my layout

[@SaintLouisFriscoLines]

Gregg, always enjoy your great videos. Hoping you can answer a question for me about the BD20s. I’m preparing to install these on my son’s layout. NCE recommends only one feeder per block. You’ve attached multiple feeders to one BD20 in some places. Is the detection working as expected in those blocks with more than one feeder? It would be helpful to know this before I start. Thanks in advance. Mike

[@FishplateFilms]

Thanks very much Mike! NCE are correct with only one feeder , but if you look at the (very rough) drawing, you will see that there is only one wire through the BD20 ie , one feeder , but then it splits to power each end of the block. This is to help with voltage drop , but only really helps on long sections of track, and me being over careful! Most times you will be fine running the feeder to the middle of the track section. Cheers and good luck with it! Gregg.

[@chucklamb3496]

Good job mate!

[@billmiddlemas5236]

Great Job Greg as always. By the way, it looks like you got a bit too much sun there from down-under ;) Make sure you take care of yourself and use some sunscreen, my friend. Keep up the great work. Cheers for now!

[@FishplateFilms]

Thanks very much Bill! We had a very unseasonal hot week and it was very sunny out on track, and the ballast reflects a huge amount of light and heat...so you get cooked from the top and bottom! Thanks for the kind words, Gregg:-)

[@farmerdave7965]

I love the BD20s. Just remember that they will only work with AC track power. DCC just happens to be AC. The bridge rectifier based detectors will work on AC or DC track power. I do not use these because of the voltage drop across the bridge.

[@FishplateFilms]

Thats' the beauty of DCC Dave! My favourite part of DCC is auto reversers..LOL. Like a dream come true for a old modeller...and of course being able to drive a train anywhere on the layout! Gregg.

[@neilrogers1571]

Gregg great clear video filled in a few blanks for me. I assume I am correct in thinking for the wiring to a second, or more, circuit brakers you would take it from the CS through a bus supplying all the CBs then feeding to there own power districts? I am planning on having 5 or 6 districts.What I am thinking on doing in my hidden staging was putting block detection on the switch/ points as well (4No) as one block eg routing, so only one train at a time can enter the block of 4 switches. Have you looked at other block detectors that can detect 4 or more blocks poss cheaper? Regards Neil

[@FishplateFilms]

Thanks Neil! You're spot on with the CB's and districts and I would certainly put BD20's on hidden turnouts so you can't throw a switch under a train! There are detectors that come on a board, I think Tam Valley make some? They work out about the same or more expensive as they combine CB's as well I think? Coming from a service background, I like to keep things separate so if a component fails, you only have to replace that and not a larger device? Of course it's up to you sir! Cheers Gregg.

[@pacbeltrr38]

That's what I get for watching these backwards! I saw part 2 first!! Wow....my brain hurts! 😵 I got what you're saying, but my Layout is just not that big. I do have a single track gauntlet track, which is a bridge over a canyon. I would like some signals on each end of that. Probably just one circuit on each double track end, before the bridge. And a few other spots, just for some "cool automatic signal changes" around the Layout! Again, my Layout is not big enough, or runs enough trains, to warrant actual expensive, real-time, block protection... Can I use BD20s to control level crossing lights? (Is that the proper Aussie term for road crossing?) .😉 Carmine 🚂

[@pacbeltrr38]

BTW..... I won't tell anyone about the unsoldered feeders - I'm not the DCC Police, I'm the Grammar Police!!! 😜

[@csnyder29]

Another great video Gregg .. what is the best way to isolate the tracks if you have already laid them without insulated joiners?

[@FishplateFilms]

Thanks Craig! Most people get the finest cutting wheel in a Dremel and cut the rail and then glue a piece of plastic in the gap and file it to the rail profile. A bit of mucking around but works OK, this is why it's a good idea to think of this when you're laying track . Also make sure to vacuum up the rail dust as you cut the rail to prevent it possibly shorting out the joint. Cheers Gregg.

[@upsd402]

Great video, one question, so every Railroad car would need a resistor? For right now I am using infrared on my detection system. It works, but has many limits. Can't wait to see what detector (system brain) you are going to use. Cheers Terry.

[@FishplateFilms]

Thanks again Terry! Yes , a resistor is needed on every car, one or two depending on your choice and around 10-15 K ohm. I used IR detection on my temporary layout , it works but is a lot more complicated and expensive. I will be using relays for now, but JMRI will be the system in the future. Cheers Gregg.

[@CajonSub]

HI Gregg, great informative video. I am diving into the block detection planning phase of my layout now and it is uncharted territory for me. Your video is very understandable and clears a lot of things up. I do have two questions though... 1) if you turn multiple feeders into another bus to run through a coil for block detection does it matter if all three feeders run through the coil or just the new bus they are tied into? 2) how do you go about location of your electronic components for block detection/signaling on the layout - Do you try to keep them all together or does it make a difference if they are spread out? I'm building a double deck layout and trying to find the best placement for the command station and a lot of the components that accommodates both levels without long long wire runs and possible voltage drops. Thanks again for all your videos, keep them coming.... - Steve

[@FishplateFilms]

Hi Steve, I'm sorry but I never got your question till now!! Im guessing you have your answers by now..LOL Sorry about that but I blame you tube! . Cheers Gregg

[@CajonSub]

FishplateFilms Hi Gregg, all good - I’ve had issues with KZbin notifications (or lack of) too. They can’t notify me for replies but they can sure recommend every other video on KZbin 😁. I did get the answers though, thank you. - Steve

[@tomelbourne5294]

Awesome vid Gregg , just a question Why is the connection on the bd20 to the red rail feeder on the passing siding and the common wire on the main ? Why must they be connected to opposite rails on different tracks, and do you connect them to the opposite rails when you get to the next block all around the layout? A little confused by this, thanks Gregg

[@FishplateFilms]

Thanks Tom! I mention in the video that I used the IRJ's that are there for the electrofrog turnout so you don't have to cut more rails than necessary. You can use whichever rail you like but if the insulated joints are there, why not use them? Funny enough , in real track blocks, it is common to switch polarity for each track section!! Cheers Gregg.

[@teddybeareleventeen]

HI Gregg! Very interesting if not a bit daunting for a non sparkie like me. $20 a turnout? I'm looking at a grand at least, not to mention the main line and sidings. But it is nice to know the tech is available! Locos look and sound good too! Cheers! Stew.

[@FishplateFilms]

Hi Stew! It's a lot easier than the real ones I tell you..LOL but very close to the same principals! Luckily most yard switches are not detected but most mainline ones are! Can you imagine how much it cost Mr Parker to install the signalling on the "Fall River: layout??? Having seen it personally , I'd hate to think ..LOL but what a layout. I see the Tam Valley installs continue Sir!! Thanks for watching mate.Gregg.

[@teddybeareleventeen]

I find it very interesting that a lot of principles for the prototype also apply to our models. I can't remember if I've seen Fall River but I'll check it out! I'm taking a short break from the Tam Valley stuff to install an ECONAMI PNP with sugar cube speaker into an Atlas LMX Leasing B39-8. I'll let you know how it turns out! Cheers mate! Stew.

[@FishplateFilms]

Very true! The engineers at work can't believe you can download a electronic programme for signalling free from the net..LOL We pay millions for ours!! Look forward to hear the U Boat! Gregg.

[@mikewalsdorf8744]

NCE BD-20's work well for block occupancy detection. I have several relay circuits using BD-20's in one of my yards on my Ho railroad. What type (brand) of relays are you using ? Thanks for posting ! Cheers!

[@FishplateFilms]

Hi Mike. They work well but I am losing some volts across the detector driving the relay , but it could be the size of the relay? I din't know what brand they are, some chinese ones from RS components. Cheers Gregg.

[@cfdtv1]

Gregg, Great video! Thanks for the explanation. I'm still in the planning stage for my layout and I've been trying to figure out which way I was going to go for block detection. You have convinced me that it's the BD20 way I want to go. One question.... I'll be using either 14 or 12 gauge wire for my main bus and was going to use 20 gauge for the feeders to the track. If I use your method of a sub bus for the block, what gauge wire do you suggest? I'm assuming I would use the same size as the main bus. Do you agree? Thanks again. Gary

[@FishplateFilms]

Thanks Gary! The wire for the "sub"bus can be smaller because it is only going a short distance and not carrying a lot of current. Also the hole in the BD20 is not that big , so a smaller wire is needed for that. My block bus is 1.5mm sq and I went down to feeder wire size to go through the BD20 then back to 1.5mm. Hope this helps! Cheers Gregg

[@cfdtv1]

Thank you! That helps a lot.

[@JoeG-firehousewhiskey]

wow, that seems complicated, I'm sure once you get into it, its easier to understand!

[@FishplateFilms]

It is a bit Joe...but nothing like the real interlocking that I work with! It does get easier when you get into it. But its cool to see trains "knock down" signals! Thanks for watching. Gregg :-)

[@joem3968]

So do I have to change all my plastic wheels to metal ones on my rolling stock for this to work

[@FishplateFilms]

One axel per car is enough Joe! Though some people prefer to do one axel per truck. If you want to be really lazy, you could do a few cars and always put them at the rear of each train!! Cheers Gregg.

[@rjl110919581]

THANKS

[@fruitgums]

You're a little mad, I like that lol

[@FishplateFilms]

It helps me get through the day..LOL.

[@Ben-kl2ev]

Does this work for dcc and dc?

[@dylanhale7300]

So how do I wire about 12 of these together, so I can automate a layout Via DCC and computer?

[@FishplateFilms]

Thats beyond me Dylan..LOL. If you mean full automation of the layout , thats a big ask! Most people would use these to operate a prototype signal system. Cheers Gregg.

[@samhane11]

What is the difference in SMD lED or led im confused>

[@FishplateFilms]

A "SMD" is a small led like the one on the front of the BD20, it stands for "Surface mount Diode", unlike the larger, normal 3 & 5mm LED's.

[@samhane11]

Do i need a resistor on the neg wire? I watched another video that he was soldering in a diode , the chap was from down under as well. but im not a pro like you gents. Most of all I want too thank you for responding. your the first!!!!!! Thank you so much. Ben A.

[@samhane11]

Do i need a resistor on the neg wire? I watched another video that he was soldering in a diode , the chap was from down under as well. but im not a pro like you gents. Most of all I want too thank you for responding. your the first!!!!!! Thank you so much. Ben A.

[@FishplateFilms]

Thanks Ben, every LED requires a resistor to limit the current flow as it has no internal resistance , like a bulb has. The size of the resistor depends on the LED and what voltage you are using, normally with 12 -14 volts, a 1 K-ohm is used with SMD and about 500-600 ohm with normal LED's, but there are easy calculators on the web to use. Cheers Gregg

[@dadnyfur]

I'm going to guess that the BD-20 does not work on DC current, but only AC, is that correct?

[@FishplateFilms]

You are correct! AC only I'm afraid. Gregg.

[@dadnyfur]

I presently use the bridge rectifier/1.4v drop detection system on my layout because at present I run both DC & DCC. I have some of the BD-20's and will install when I switch to an all DCC system.

[@joem3968]

Where do i buy NCE bd 20 's from for $20.00 Greg mate . Thanks Joe

[@FishplateFilms]

Hi Joe. I got mine from Model Train Stuff in the US .even with postage and the exchange rate, it was still cheaper than down here! It's a shame local shops need to charge so much? Cheers Gregg.

[@bigdon1a1]

what about the bulbs

[@brentseizer1019]

The audio is terrible. You speak way too fast, and you need a microphone closer to you so that there is not so much echo.

[@Tcostello105]

Might want to get your hearing checked chap. Video is great. Audio sounds fine.