Pulling power

Hard cash might shut me up - but only for a short time.

Anyway dont rewire, just have the ability to switch everything (except above complex things) live. Then you have a choice of DC and DCC. I dont plan DCC'ing all locos, too time consuming, too expensive in one go and as chips/systems evolve over the years may upgrade some locos and move lesser chips to others. Also sometimes want to play roundy, roundy. Dont need DCC for that !

Cheers, Simon

How do you do train detection with DCC ?

Simon

Greg Procter wrote in news: snipped-for-privacy@ihug.co.nz:

Enough already isn't it enough that I have agreed to vegitate my brain and try dcc without talking me in to changing my existing layout with it's (if I may say) perfect for my purposes DC wiring?

There are two separate things to be detected:

- rolling stock at a specific point on the layout. I use an LDR plus home made circuit.

- rolling stock in block. I use a diode bridge in the block wiring to detect current draw.

- On an earlier layout I simply used a small bulb wired across the block on/off switch to show a parked loco. Mk II used the same bulb but also a PWM controller and bipolar capacitor so that the bulb lit with (almost) constant brightness whatever controller setting above "0" was used.

Both work with DC or DCC.

Regards, Greg.P.

a:- I'm arguing _for_ DCC, that's gotta make someone somewhere splutter into their cuppa tea! b:- just wire in your DCC controller as if it is one more cab-control controller, NO other changes to your perfect wiring are needed. I can talk you through that step if required. How else can you honestly reject DCC if you don't give it a fair trial =8^) (other than spending the money on another loco that you desperately need)

Regards, Greg.P.

Greg Procter wrote in news: snipped-for-privacy@ihug.co.nz:

Strangely enough for a Pom I can't stand the stuff!

Why thank you, but whan you say "your DCC controller", I really ought to advise you that I have no DCC controller and as I'm just about to spend the best part of £500 on track I can assure you that I won't be in a position to dash out and buy one anytime soon.

So very true especially as most of the stock I'm looking to buy is only available in kit form. :-(

I am though slowly coming around to the idea of trying it on what will be the 009 section of my layout. I'll need a third controller for it in due course in any event.

In message , simon writes

Don't you believe it. The most exciting "roundy roundy" I've done was with four locos on the same track. These were all Bachmann 56XX 0-6-2Ts, which obviously all ran at different speeds. DCC was very useful to keep them apart, and the excitement came from trying to remember which hand controller was set for which locos.

I found to my surprise, feels quite light, the Q1 from Hornby can pull alot, much like the prototype. Much more than the unrebuilt BoB from the same manufacturer, the LN from Bachmann and a unrebuilt BoB from Wrenn (and that is heavy) as you can no doubt guess I have a Southern bias.

Chris

join them up logically as if double headed then only need 2 controllers! But until can annexe the loft theres only room for them to be light engine on a 6'*4' oval.

You can't be a Pom!

Ok, so wire in someone else's DCC controller, the wires don't care. ;-)

You start off on the right track.

Yes.

These can easily be switched automatically.

These are not *switched* blocks.

Plus all the other blocks typically found on a DC layout for route setting.

MBQ

snipped-for-privacy@ihug.co.nz...

Optically - can be error prone. Modulated Infra-red is probably best. - DC or DCC

On train Transmitters such as Uhlenbrocks LISSY - DC or DCC

Proprietary bidirectional communications such as Lenz Railcom or Digitrax transponding - DCC only. Before anyone says anything, Railcomm is *not* yet an NMRA standard and so still is Lenz proprietary.

Current transformer - DCC is AC so you can pass one track dropper through a current transformer and detect the current when a train is in the section. Detector is isolated from the track supply.

Voltage drop across diode(s) in one track droppper. Remember DC is AC so you need "anti-parallel" diodes to allow the current to flow both ways. Detector circuit usually takes its power from the track so you need to be careful with isolation (use opto-isolators on the output). Non-detected sections need the diodes as well to balance the voltage drops.

To detect stock other than locos, the same "resistor wheelset" technique as used for DC can be employed.

MBQ

Chris wrote in news:5_2dnQ_knvj7m snipped-for-privacy@bt.com:

Thanks, it's about 20 years to young and 200 miles to south :-) but certainly worth baring in mind.

They are just as easily switched with a relay or add on point motor switches and at a much lower cost.

They need to be isolated blocks for train detection.

Those are all required for DCC and proper signal/block operation.

messagenews: snipped-for-privacy@ihug.co.nz...

That gives you detection at a fixed position or of a train passing but will not detect an entire train stopped 1 cm from the detector.

Those tell you the identity of a loco on the layout - they don't tell you where it is.

In that case you need blocks. (unless of course you only want to detect whether there is any train on the entire layout.

Indeed. There's always a decision to be made as to whether you want to know that theres any train or a specific train anywhere or in a specific place. The answer to that question will influence your choice of detection method. You can also combine detection with dead reckoning and a description of the track plan in software.

Wrong. LISSY is an IR system and localises the trains position by knowing which detector picked it up.

The same is true of any detection system. You can only localise it to a particular point on the layout by sectioning the layout into detection zones.

MBQ

Agreed. But this is local switching. I was thinking of blocks switched from a control panel.

Not switched blocks then. A few insulating rail joiners with detectors in the local track droppers.

No.

I'm thinking of a fairly comples station throat and the way it would need to be broken into small blocks to allow two simultaneous routes to be set controlled by different controllers. Each block wired back to the control panel. With DCC it's all connected together and you drive the trains, not the layout.

Proper Signalling and block operation does not _require_ the layout to be split into blocks.

The only place you _need_ blocks with DCC is for power management, return loops/wyes and detection zones.

MBQ

The blocks don't need to be switched for detection, either for DC or DCC. Switching is very handy for fault finding.

OK. Your choice.

Sure - In my modelling I try to simulate a busy section of railway. I can't possibly drive all the trains, one is quite enough. DCC and driving the trains isn't an advantage to me as my layout works in blocks.

I'll agree that there are various ways to operate one's trains. I tried DCC and found that costs were going to escalate to extremes for no great advantage, so reverted to analogue control. The downside of my particular system is that the wiring overall is relatively complex (made up of basic wiring modules) but the cost is much lower and I can achieve more.

Exactly. However, those are the same places that electrical blocks are required for analogue control.

Regards, Greg.P.

tection, either for DC or

usy section of railway. I

I think we'll have to agree to disagree ;-)

MBQ