Hornby DCC Power And Accessories

[Bigmandanc]

Hi there, I have a SCARM layout designed for my room, but I am a total newbie when it comes to DCC. I was wondering if any of you Hornby Masters could have a look at my SCARM, and help me figure out what wiring I need etc, I have researched it, but I cannot quite wrap my head around it. Any help appreciated. I can PM in either SCARM format or Atlas format (I make the sections in SCARM, then load into Atlas to join together  😛 )

 

Kind Regards

 

Dan

[96RAF]

Dan

Unfortunately the forum doesn't have a PM facility and the rules forbid posting of personal details like phone numbers or email addresses.

 

Just take a screen grab of your Scarm plan on your PC and post it to the forum using the black and white icon at the top of the reply box (just to the left of the smiley face). The picture will not appear immediately as it has to be moderated not by us Mods but by the site Admin, during UK office hours only.

 

People here can then look at it and make comment.

Rob

[Bigmandanc]

/media/tinymce_upload/3acff0adfe97a34d2c50bf243a2629cc.jpg

Here you go. Best I can do right now. Is there another popular board that you guys use where I can upload this stuff?

 

Kind regards

 

Dan

[Chrissaf]

The triangular section highlighted in yellow is a WYE. It will need to have a RLM (Reverse Loop Module) fiited in addition to some IRJ (Insulated Rail Joiners) else you will get a 'Short Circuit' when you try to use it. In fact there are two WYEs, the one highlighted in yellow, plus another created from the loop next out from the yellow section. The vertical transfer track (in the left hand side of the yellow box) is common to both WYEs.

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Assuming the TT is a Hornby R070, then that will also need to be modified for a DCC layout (again to prevent DCC short circuits). 'How To' is decscribed in these 'forum user' generated tutorials.

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R070 Turn Table DCC Modification

http://www.hornby.com/uk-en/forum/r070-hornby-turn-table-to-dcc-including-images/?p=1

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R070 Setting Up configuration in RailMaster

http://www.hornby.com/uk-en/forum/r070-turntable-configuration-in-railmaster/?p=1

[Chrissaf]

Further to above, what is going on here. Please explain.

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Is this supposed to represent tracks on two different levels. If so, then I can't see how you can possibly get enough run up space to have a workable slope gradient.

[2e0dtoeric]

Two more Wyes, as well, both on that central section, where there are two more sets of cross-overs! Would the one module cover all three?

[Chrissaf]

Eric, that whole design in the central area is effectively a series of nested (Russian Doll - one inside another) Reverse Loops. The design is a bit of a RLM nightmare and would need very careful assessment given the sheer number of track to track cross-overs included in the design as well. At first glance, I would think it would need a minimum of two RLMs and a lot of IRJs to resolve. I would want to know the answer to my second question (my "Further to above...." post) before I expended time trying to formulate a RLM proposal.

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It is a case of trying to cram as much as possible into a small space. SCARM lets you do it. SCARM doesn't comment on the practicalities of whether the design is technically workable or not.

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PS - Just spotted that SCARM is an anagram of CRAMS 😀

[Chrissaf]

Another potential issue is the input rail to the TT. Being a Y point the TT input is effectively directly connected to a curve track. There is a very high risk that will create a consistent derailment location. It is reported on the forum that the Hornby TT works best if there is a straight track piece directly connected to the input track. The suitability of a 'point' for the TT input is compounded because the Hornby TT generates a slight sloping rise on the input / output track pieces. Hornby points need to be perfectly flat, if they are not going to cause derailments or loss of loco pickup power. Not sure that a point 'toe end' directly connected to a TT input track would have enough space for an underboard point operating motor.

[2e0dtoeric]

SCARM/CRAMS/SCRAM!

Whatever - an electrician's nightmare for a dc layout, too!

[Fishmanoz]

Given you are new to this Dan, may I suggest that you think some more on what you want to do on your layout and how you want to do it.  You may well find it can be achieved with a simpler design.

[Bigmandanc]

Hi guys, thanks for all the responses. That funny looking track can be removed near the turntable, was just an idea for a custom piece. The layout is exactly how I want it, I know it won't be easy to wire, but I have to fit a lot into a small space.im massively great full for all your help. I'm expecting complications, and I'm aware of isolation etc. The turntable will be sunk so it is all perfectly level and it is manual, not electric.

 

Thanks again

 

Dan

[Bigmandanc]

Also, all point motors etc will be underneath the board. 

[Chrissaf]

Bigmandanc,

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Your layout plan creates multiple 'Reverse Loops'. Reverse loops generate short circuits on a layout. I define a 'reverse loop' as:

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"any route path in a layout that allows a loco to arrive back at its starting track position but facing in the other direction"

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Your whole layout plan effectively allows that definition to occur through multiple routes and paths. The only way I can see to protect against all these possible route paths is to split your layout horizontally into two power areas and protecting the cross overs locations from the upper half to the lower half by RLM 1 and the inclusion of multiple Insulated Rail Joiners (IRJs) shown as Red bars on my drawing below.

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Even then, the design is not 100% ideal, it is a compromise that is doing its best to accommodate your very unusual layout design. The area of the design (for RLM purposes) that concerns me most, is the number of cross-overs in the central area that constantly criss-cross back and forth between the upper and lower power areas (along the route of the dotted line separating the upper and lower halves). If for fun, you set a route that uses then all at the same time to make the train switch back and forth between the two horizontal tracks, then that could impact the function of RLM 1 as it is constantly trying to switch back and forth. Note: that is not just the loco that triggers the switching of a RLM, it is also the metal wheels of any rolling stock the loco is hauling.

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The one Key flaw in the RLM design.

There is a potential key flaw in the design, that I cannot see any way out of with the layout design you are proposing. You should only have one train crossing over between the upper half and the lower half at a time. If two trains (a train is a loco plus rolling stock) cross-over at the same time, RLM 1 may have to start switching very rapidly to constantly try and remove the short circuits that it is detecting. The RLM is switching very fast indeed, but the constant high currents being drawn (due to the pulses of current being drawn as a result of the 'short circuits') may be enough to trip the controller or its attached power supply. This is not so much an issue when the two trains in question are both crossing the power areas on the outer loops (because all the rails will have the appropriate DCC phase signals on them), but would be an issue if one train or more train is crossing the outer loops, at the same time as a train is traversing the cross-overs in the central area. It is these cross-overs in the central area that are the crux of the Reverse Loop dilemma.  See 'In conclusion' at bottom of post.

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Some important notes, that you must adhere to if the RLM design has any chance of working. This assumes that due to the sheer number of points in the design that you are not going to rely solely on R8232 DCC point clips for the transfer of power around the layout. So, if you intend to install additional power feeds ( a DCC Bus for example), then it is imperative that the DCC controller is not wired directly to BOTH the upper and lower power areas. Power to the upper area MUST go through RLM 1.

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Let's assume that the DCC controller connects to the lower power area. Any additional power feeds serving the lower power area can be safely connected directly to the controller. However, any additional power feeds that you install on the upper power area MUST not be connected to your controller, they can however be connected to the output of RLM1 that connects to the upper power area. Remember that any additional power feeds you install, MUST be connected the right way round else you will get an INSTANT short circuit.

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TurnTable - IMPORTANT NOTE

You say that the TT will be manually controlled. Not an issue with that, but the TT must still be modified for use on a DCC layout as the Hornby R070 is designed specifically for DC layouts. The 'How To' modify the TT for DCC use is in the link of my earlier reply.

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Due to the Y point leading into the TT, it is necessary to install a second RLM 2 as the Y point does not allow IRJs to easily isolate the two routes through it. I have also moved the Y point back to allow a straight section of track to be used as the entry into the TT, this will help to alleviate derailments and provide adequate under-board space for a point motor.

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With regard the RLM - Reverse Loop Module.

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Hornby do a RLM [ R8238 ] but this is now obsolete. Stocks are available at Hattons and are heavily discounted to sell (being obsolete). Other brands of RLM are available. I use those made by 'TamValley'. Note that if you do use the Hornby R8238, there is a selection switch marked 'Select or Elite'. Ignore the terms printed on the RLM switch. Use the 'Select' position if you are using a Hornby 1 Amp power supply OR the Elite position if you are using the Hornby 4 Amp power supply.

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If anybody else can see an alternative way of achieving a different RLM design more simply, then please post. I am more than happy to accept an alternative idea if it can be proven to be better or more effective.

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In conclusion.

Personally I would not try and build this layout as it stands. The Reverse Loop complexity could be eliminated at a stroke, if all the cross-over points to the right of RLM 2 are removed (the ones with the IRJs shown on them). If those points were removed, then RLM 1 can be removed, all the IRJs can be removed (with the exception of the Y point near the TT). RLM 2 and the Y point IRJs would have to remain, else the reverse loops would reappear again. A full DCC power Bus could then be implemented to cover the whole layout (all connected to the controller) with the exception of the TT area protected by RLM 2.

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This small change to the track layout design appears to me to be a small price to pay for the benefits of the trouble free operation that the removal of these points provide.

[Bigmandanc]

Bigma....c, a power plan will be posted shortly, please check back later.

That's amazing, thank you.

Wow, that is alot of useful information. Made a few things click in my head. I'm sure I will have more questions once I have all the parts. You sir, are a legend!

 

Thanks again

 

Dan

[Chrissaf]

Bigmandanc,

I have heavily edited my reply since the time stamp of your last post, added new suggestions and comments etc. I post this reply to bump the post and bring these later edits to your attention. So do please re-read the reply in total again.

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Chris

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PS - Would be useful if you could acknowledge that you have seen the edits. Thank you.

[Bigmandanc]

Ok, saw your edits, thanks again. Do you use scarm yourself? Ideally I would like at least one set of crossovers there. When I get home on Monday I'll crack open the scarm and see if I can figure it all out. Thanks again Chris.

[Bigmandanc]

How about if I had a single track down the middle near rlm2? Then I could insulate one side. Would that work? Thanks again

[Chrissaf]

I used to use SCARM when it was completely free, but have since uninstalled it as it kept niggling me to buy the paid for version, and as my track is now laid I really don't have any use to pay out for it any more.

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Without seeing it (single track down the middle) drawn up for evaluation it is hard to say, my initial reaction is that I think it might make it worse, but that maybe because I can't quite visualise exactly what you mean. Cutting back your design to a single cross-over in that middle section would help a lot. You would just have to be observant when you used it, with relation to the positions of other trains on the layout for the reasons I described in my edited reply.

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PS - I couldn't quite see the benefit of having a double lot of double cross-overs in that section anyway....it seemed overkill to me.

[Bigmandanc]

I used to use SCARM when it was completely free, but have since uninstalled it as it kept niggling me to buy the paid for version, and as my track is now laid I really don't have any use to pay out for it.

I found a way around that lol. If you make sections in scarm, you can load them into atlas, and join them all together haha

[Bigmandanc]

I used to use SCARM when it was completely free, but have since uninstalled it as it kept niggling me to buy the paid for version, and as my track is now laid I really don't have any use to pay out for it.

I found a way around that lol. If you make sections in scarm, you can load them into atlas, and join them all together haha

I will draw it up Monday and post it here. 

[Bigmandanc]

I used to use SCARM when it was completely free, but have since uninstalled it as it kept niggling me to buy the paid for version, and as my track is now laid I really don't have any use to pay out for it any more.

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Without seeing it (single track down the middle) drawn up for evaluation it is hard to say, my initial reaction is that I think it might make it worse, but that maybe because I can't quite visualise exactly what you mean. Cutting back your design to a single cross-over in that middle section would help a lot. You would just have to be observant when you used it, with relation to the positions of other trains on the layout for the reasons I described in my edited reply.

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PS - I couldn't quite see the benefit of having a double lot of double cross-overs in that section anyway....it seemed overkill to me.

That was so trains could swap internally no matter what track they used without going on the main lines round the outside. I'll revamp it Monday and follow up

[Chrissaf]

Dan, it would be helpful if you tried to avoid using the 'White Arrow in Blue Button'. When the dialogue is two way and free flowing as these last few posts have been, all the repeated text in the yellow boxes becomes distracting for readers unless heavily edited to remove the unnecessary sentences from it.

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Where you want to specifically mention something from a previous post to reply to. Just copy and paste that piece of text in isolation and use the 66 quote tool in the reply text box. Just as I demonstrate below (using a cut and paste from within this paragraph):

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Just copy and paste that piece of text and use the 66 quote tool in the reply text box.

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Notice how you can layer the tools, one on top of the other. I have used both 'Bold' and 'Italics' both separately and together in the 66 quote box to format the text. Using cut n paste with the 66 quote tool makes for much more readable replies compared to using the 'Blue' button to re-quote everything verbatim.

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Take your last reply, all you needed to re-quote (if at all) was the last PS sentence. The rest of the yellow quote box text was superfluous duplication.

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Not having a go or being critical, just offering a 'TIP' for the ongoing harmony of the forum. It saves page space too, particularly when re-quoting my long replies.

[Bigmandanc]

Noted Chris lol. Not the most user friendly forum is it haha.

Thanks again

Dan

[Chrissaf]

I have had a re-think on the RLM design and I have a Plan B design that will allow you to keep all your centre area cross-overs with minimal operational issues.

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It will mean increasing the number of RLMs from two to four, but it is a more elegant design that still allows you to keep your multiple centre area cross-overs.

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In order to make this RLM plan work, it is necessary to maintain complete rail polarity consistency for all the power connections to tracks in the horizontal plane. To help visualise what I mean by this, I have added a conceptual and simplified drawing that represents (at a basic level) your track plan, with individual track rails colour coded as brown and blue. The red bars represent the IRJs from the drawing above. Only one oval loop shown for simplicity of creating the drawing.

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Notice that only Blue rails connect to Blue rails AND only Brown rails connect to Brown rails as you move up and down all the horizontal tracks. Normally in a tail chasing oval design, the upper half of the oval would have the Brown and Blue rails reversed on the the top half of the drawing. It is your central area track cross-overs that prevent this from being possible. You can see that if the outer tracks of this drawing were extended round to join together (the black dotted lines), you would have a 'short circuit' via the Blue rails and Brown rails meeting together on the ends of the loops. This is where the four RLMs come into play.

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As trains leave the central area represented by the Brown/Blue drawing to traverse onto the end loops, the RLM reverse the track connections to remove the short circuit condition. Not only that, but with four RLMs, with one each dedicated to protecting an individual end loop, the chances of two trains crossing both ends of a RLM protected section simultaneously are very much reduced. Trains can be left circling round the ovals under autonomous RLM control whilst you move your trains and locos within the central area to your hearts content without needing to consider what the trains on the loops are doing.

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IMPORTANT NOTES:

When putting in extra power feeds and droppers it is very important that you maintain the rail polarity as indicated by the Brown and Blue rail colours. If only one single power feed is reversed you will get a short circuit. To be belt 'n' braces I would check for a short using a meter as you connect each individual track power connection to double check.

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Again as before, your controller must only directly connect to the central area and must not be connected to the four end loops protected by the four RLMs. All power to the end loops MUST go via the RLMs, else you will circumnavigate the RLM protection function, which may also damage the RLM.

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One other key RLM requirement to be aware of. The RLM protected end loops must ideally have track sections that are longer than your longest train (a train is a loco with all the hauled rolling stock included - because of the metal wheels). I don't see this as a problem on the Station end and it shouldn't be a problem on the left hand side either, but I have no idea what length of train you intend to run on the loops. What you can't have in an ideal world, is a train exiting a RLM protected track section, whilst the other end of the train is still in the process of entering the same RLM protected section. It confuses the RLM electronics and can cause switching instability.

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This Plan B design eliminates the short comings of my first design attempt, at the expense of needing two additional RLMs.

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Note that the R070 TT still needs the DCC modification in this design. The R070 TT would need to be DCC modified even if you had no reverse loops in your layout at all.

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Just as an aside, this track design would be nearly impossible to achieve on a DC Analogue layout. There are no automated RLM products for DC Analogue. Think about it, on DC Analogue you reverse the track polarity to reverse the train direction. If this layout design was DC Analogue you would have to have a very complicated manual track section switching arrangement, with lots of toggle switches and extensive track power reversal wiring.

[Bigmandanc]

Wow, you rock! I'm very happy now. I'll just make my trains shorter that the left hand loop, or I will buy plastic bogeys for all the rolling stock, that's no issue. I will DCC proof the TT, definitely. And I will definitely be testing it as I install. I briefly thought about doing it dc, but after about 3 seconds I realised it was impossible, just on the controllers alone. Too much needed. Once it is ready, I will be converting the locos that I have to DCC, so that'll be interesting.

Kind regards

Dan

P.s.

I assume if the train is long enough( say intercity, with coaches on plastic bogeys,) that the power car crosses out of the rlm before the dummy comes in, that will be fine? Also where would you recommend I put the power piece? Cheers

 

P.s.s

Before I purchase to much track, I'm currently using hornby, but I've heard alot of praise for peco track. Is there really a great deal of difference?