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Yes. Sorry if "I have a separate PCP in a box to feed it, the NCE PowerCab is physically disconnected from the layout and connected to this entirely separate track." wasn't clear. Obviously the way you do it and the way I do it is completely different, and from what you are saying you get what Nigel expects. I am going to try to see if I can set things up so that I get what Nigel says I should get - but I don't see how at the moment. Indeed Harold. I hope that that is what they will offer to do. But they haven't yet. I cannot just send them the chip unless they agree to accept it.

The NCE web pages say as follows: If you want a dedicated programming track to use with you Powercab we have the AutoSW for that purpose. The AutoSW is a smart relay board with one input (two wires from powercab output) and two outputs. One output for the main layout and a second output for a programming track. The Auto_ SW senses when you put the PC into program track mode and energizes a relay that disconnects layout track power and connects a dedicated program track. The auto sw is designed to detect packets on the DCC track bus that initialize service mode programming aka- programming track mode. When it sees those packets it throws a relay disabling one set of outputs and activating the other. How does that do what you say it should, i.e. provide no power to the program track? I have a further problem in that this seems to assume that the program track is an integral part of the whole layout and that you wish in some way to isolate it when you want to do programming. If that's right - then since I have a completely separate piece of rail how does the switch help me? Currently I have a separate PCP which is wired to a separate piece of rail, so I don't need to isolate it from the layout (presumable so I don't accidentally reprogram some other loco) since it stands by itself anyway. I am sure that it would be really helpful if I could get my simple mind round this!

Thank you. Yes I do know about it and mentioned the decoder tester in earlier posts. It's really a case of I have never had any trouble before nor do I expect any more. I have 36 DCC loco's (many with sound) with no problems and this particular Zen chip has misbehaved/been fried and I think I shall just cut my losses. Either the manufacturer will replace it or not, but the decoder-tester costs the equivalent of 2 new chips with stay alive and so I would think it not likely to offer me much return for the money.

Well thank you for all your attempts to help me. This is what I have tried: 1) un-solder grey wire from Class 37 motor, put Zen chip in socket of Class 37, put PowerCab into PCP socket, set Program Track, try to reprogram but cannot read CVs 2) place Class 55 with chip on program track as well as Class 37 as an attempt to provide "ballast" for the process, repeat 1 above, still couldnt read CVs on 37 but could on 55, managed to cause short address of 37 to go to 3, but setting CV 8 to 8 seemed not to do anything. 3) re-soldered grey wire, moved Class 55 (Hatton) chip to Class 37 chassis checked that DCC control and reprogramming worked OK on that chip on the 37 chassis. 4) removed Hatton chip and inserted Zen chip, put heavy weight on wooden box at end of track, connected Power Cab, 37 chassis with Zen chip, chassis pushed wildly against box, tried setting "program track mode" it reported "short circuit present" so ceased the experiment. It seems to me that there is a short within the Zen chip - since the Hattons one works properly - and that it is therefore unusable. I am not doing anything more. Either DCC-C accept that there is a problem and hopefully replace the chip or I am £17 out of pocket and I'll buy a chip that works. I am in contact with DCC Concepts and will pass the current progress to them.

I dare say it is but I'd rather like to do this without completely dismantling the chassis. IF that's the only way to reset this chip I think I don't want it!

Thank you. It's obvious when you stop panicking and think! Which is why I asked on here, cos I was doing the panicking. I'll try that when I get some time this weekend.

Yes I do know that. Believe me I'd really like to, and if you have any ideas on how to stop the loco shooting off so I can establish control for long enough to do anything I'd be most grateful.

Sure is a problem of understanding - mainly mine but I am trying to catch up. I put the PowerCab into "set program track mode" and my trusty multimeter assures me that there is 13.5 volts AC there. It's only a cheap Maplin one so it probably isn't very accurate, but there is AC power there. "Normally" behaving locos of course just sit there - the duff Zen chip likes the power and goes wild. Sorry but you are possibly in error or my PowerCab doesn't work properly. It is possible but it seems to do everything else right? Anyway I think I have proved the chip is duff - see posts 13 and 17 above. Happy for any other comments from you - I NEED to learn these things.

Well that's that then. Having proved that it works in DC mode, I have taken the DCC Concepts Zen 360 out of the 8 pin socket and recovered a simple Hattons 8 pin chip from a Class 55. Doesn't go like the splendid Zen did, but at least it performs properly and proves I hadn't done anything wrong anyway. The conversion is correct and works in either DC (with blanking plate) or DCC with the Hattons chip. I then put the Zen into the Class 55 and it showed the same symptoms - trying to rush of the track. As a final test I cut off the stay alive and again tried the Zen in the Class 55 - and it still did it's flying rush. The Zen has failed - but why I don't know. I have contacted DCC Concepts to see if they have any suggestions - but await a reply. When I get one I'll let you know. Great relief - I DIDN'T cock up the conversion after all!

Well, just to prove one thing I have just removed the chip, inserted a blanking plate, attached my DC controller to the "programming track" and driven the chassis back and forward in DC mode. It works fine. If I put the chip back in and set up the DCC controller it flies off the end of the rail - just caught it! - before I can do anything (such as set the rail in "set program track" mode or even put the loco address in).

This is the nub of my problem. The program track is a piece of Peco ST-204 (about 650 mm?), I have a separate PCP in a box to feed it, the NCE PowerCab is physically disconnected from the layout and connected to this entirely separate track. Other locos perform properly (i.e. sit there and do nowt until given a command). This loco when put on the powered programming track - but without the NCE POwerCab having its loco number set or any accelleration set - goes wild.

That's exactly what I thought too. BUT IT DOES hence my initial belief that this was a damaged chip - since I believe that the only power to the motor (orange and grey wires) gets there via the chip (unless I have something horrible wrong). Maybe I'm confusing people by calling something a programming track. Mine is not in a "use program track" mode unless selected by the PowerCab, its just a DCC (AC) powered piece of rail entirely separate from my layout.

Unfortunately not. The moment the wheels hit the rails it goes into flat out running. I cannot do anything with it for fear of the motor overheating. Both bogies need to be on the track as the left line feed only comes from the rear bogie - so no way to read anything!

Thanks Phil. Yes the suppressor is out, has been from square 1. Do you mean something like an ESU 51900? I don't have anything but other locos, and I'm a bit scared of putting the chip in another loco! As you will understand I have no way of interrogating the chip in it's current location.

I have just started doing my own chip fitting, and am moving on to non-DCC ready locos. So this was an experiment and as such no big deal BUT..... I really need to try and find out what went wrong to prevent recurrence. It's a Lima 37 chassis so nothing special, one of the two wires to the rear bogie sort (some have only one - I have one of those too) ideal for a low cost experiment. I cleaned the wheels (old and filthy) to make sure it ran on DC (on my programming track with a DC controller attached), it did. I wired in an 8 pin female socket with a pre-attached loom. Put in a blanking plate to make sure it still worked on DC on the programming track, it did. Put in cheap generic Hattons 8pin chip to see if that worked, attached NCE PowerCab to programming track and it worked fine. Moved on to DCC Concepts Zen 360 with stay alive. Result was wonderful, got a slow crawl, ran well on the full layout after fiddling with the back to backs. Really amazed and really pleased. Pride went before a fall! There were two things left to do: cut off old large tension locks and replace with NEM pockets for Kadees and "ease" the chassis so that a Hornby Class 37 body would fit. The NEM fitting required a lot of mucking around with the chassis upside down. When I came to fit it all back together with the body on and put it on the track the motor ran at full speed and had to be taken off the track rapidly. This is a fixed performance, I cannot put the loco on the track it seems to be at full power. I assume therefore that putting it on the track again shorted something in the chip resulting is this aberrant performance. All wires are still soldered, all shrink wraps are still in place. I can find no bare or worn wires. So it went from a wizzo DCC chassis to a useless completed loco via being upside down for a while whilst bits were cut off and others filed so pockets could be stuck on the bogies. I changed nothing electrically deliberately. Maybe something in one or other of the bogies shifted? Any ideas? Help in where to look would be appreciated.

The shunt was not actually blocking the line at the time the train was accepted past the Home signal up to the Section signal. The train is now standing at signal 3 (Section signal) and the shunt is taking place across its rear (which is why the distance from the safe overlap to the Section signal must be > the length of the longest train) but protected by the (locked) Home signal. Mike said that if the shunt were to take place, then the Section signal would be locked. I said I could understand the Home signal being locked but not the Section signal.

Sorry to be asking questions from a few posts back. Mike, please bear with me, but I don't understand that one. I understand that in the "typical station layout" that the Block Section/Station Limits for this Block Post run from signal 2 to 3 UP and from 12 to 11 Down. I quite understand that railway signals are not traffic lights, so a train running to WTT may stop at a passenger platform for passengers to alight/join regardless of what signals are there and where the platform might be in a Section, and that because a signal at or near the end of a platform is "clear" it merely means that the line ahead has been set clear in conjunction with the box ahead and does not mean that a train due to stop should simply pass through the station. This is emphasized by the down platform where the signal is considerably in advance of the marked passenger platform end. SO we now have the situation that an UP train which has been accepted into the Block after passengers have alighted etc. has been held at signal 3 because clearance has not been obtained from the Block Post ahead. I presume this would be in order, since that move into this block (station limits) would allow the preceding block to be cleared for a following train. It was being suggested that a shunting move could take place from the Up yard to the Down line as controlled by ground signal 10 whilst this train was held at 3. You said this would be OK BUT that signal 3 would be locked by that move, and would be unable to be released until the shunt move was complete (and points/signals reset). NOW I can understand that 2 would be locked since any approaching train would otherwise run into the shunting move (or move off from the platform into the shunting move). But why 3? It would only be cleared when the next block was clear. Or is it the case that a train would not be accepted into this block unless the next block were clear - hence both 3 and then 2 would be cleared, so the train would rest at the platform when there had been no acceptance from the block ahead. I am running to get behind the sofa right now .............!

Thank you so much for that link. I won't understand it all - but I will have many hours of happy reading!

Try typing "loading milk tankers" into the search box top right, it will give you a list of threads all about the things you want to know.

Thank you. I of course recognise the layout now. I'm sorry I bothered you - but the sketch seemed full of potential disasters and I just hate it when people fall flat on their faces having spent a pile of money. The radii are not a problem since you have laid everything out in reality - since the board is only 4' wide they must be well under 2' radius so I hope you have checked your stock goes round it?. However there does seem to be a problem where the return loop meets the main - or is that just my eyesight? I haven't looked back - I presume you did check out the gradient as well?

I don't know your level of knowledge and experience in railway modelling - so I hope this isn't too basic. Please may I make some suggestions on your layout plan? To signal it in a prototypical way you need to think about making it look like the prototype. Your plan looks nice - will give play value but may have a few problems in execution: 1) is the station intended to be on top of the tunnels? If so have you thought how you are going to put in the climb up from the main loop? Since the plan is dimensionless I cannot tell how much space you have for it. If you're not putting one on top of the other how are you going to build a station between two mounds? 2) the idea of a reversing loop to get trains back to the station is good. How about the size of the curve? It needs to be at least 2nd radius if you are using Setrack (Hornby/Peco). The geometry could be a problem with the space you have. Why not use a design package like Scarm or Anyrail to see what fits? 3) you really should not have a point just outside a tunnel like in the middle of your layout, how are you to shunt the siding - the loco is in the tunnel! Maybe think of running that line from the yard upwards across the return loop? 4) your sidings in the middle are a good idea, and you have a run-round to allow the engine to pull out the train for shunting. But - in order to shunt you will have to go onto the main line and block it. How big do you want your trains to be? 3 coaches, 4? For 3 coaches and a loco you need at least 3'6" of platform length. Your crossover between the platforms is prototypical but will only work if the platforms are long enough for the engine to run round the stock in use. PLEASE don't think that I am just being negative for the sake of it. There is nothing worse than having a scheme that works in your head and finding it is impractical. If this is under 8 feet by 5 feet I don't think it will work in reality, and boards that big are very difficult to put up and take down. You may find it helpful to look at example plans in books to get a better idea of what is achievable in the space you have available.

I seem to have hijacked the topic - for which I apologise. Thank you to the Signal Engineer and Clive Mortimore. that was most useful: to me at any rate.

So 4'6" from running rail in old money? 18mm in 00 gauge? Does this go for GPLS too? Thanks.

I can only respond from my youthful recollection - but there was a guard and guards van at the end of the passenger carrying portion of the car carrying train. I know because bicycles and other extra luggage went in there (to be put on back on the car roof after arrival). It was checked in and out by the guard. The car carrying CCTs were always shunted on after we had boarded. I don't think I remember a guards van at the back of that - but then I was young and didn't think about those things.

I have been fascinated by the information made available in this thread. The knowledge and expertise available here never fails to impress. May I ask a question (that simply reveals my ignorance) please? I am used to the "structure clearances" diagrams that are around for various scales - showing clearances for bridges, tunnels, platforms etc. They don't show signals, or other line side gear (except by implication). The diagrams in this thread seem to imply that (modern?) dimensions centre rail to centre signal must be a minimum of 2 metres (unless I have misread). Is this advisory or hard requirement? I am sure I have seen signals MUCH closer to the rail that 6ft ????