DCC is the future

But you still need to purchase a decoder, fit it in, and often the circuit board needs modification, not really DCC ready. 'DCC ready' is a misleading advertising slogan, nothing more.

The cost of RTR DC/DCC sound decoders in locomotives still makes the model more expensive, and so I expect these models to be in the minority for some time. Also space to fit speakers is limited, and the sound is not that good because of the small speakers.

consequences."

Depends on the prototype, most I know of using automatic signals use track circuits. Optical detectors have a number of disadvantages compared to track detectors, one is changing light conditions, people casting a shadow ect. Then there is the extra work to mount the detector and in many cases a light source. An unprototypical device which needs to be hidden. After this extra hardware comes the extra wiring required, unlike track detection which uses the necessary track feeders. Finally position detectors need extra logic to remember if a section is occupied, making hardware solutions more expensive compared to track detection circuits.

The VR locos have outside frames.

Mark.

"John Dennis" wrote

I also have one somewhere in VR (Victoria Railways) blue/yellow livery, but this quite clearly has the VR initials on the side. I can't readily lay my hands on either of the Aussie 08s, but I am 90% certain that the box for the tuscan red/yellow version is marked NSWR on the box.

John.

"Mark Newton" wrote

Yes, so did the ones which worked in the UK but that didn't stop Tri-ang/Hornby representing both with inside framed models.

John.

I haven't seen either model, but it sounds as though Triang simply used an existing mechanism for their 08s?

Mark.

"Mark Newton" wrote

Yes, basically the Jinty 0-6-0T chassis.

John.

In message , Terry Flynn writes

Another is the length of the section that the detector is able to cover. If your sections are 30 feet long (as mine are) then your optical detector is not going to be able to cover all of that.

I have the ideal light source for my layout. Unfortunately it is only available during daylight hours ;-)

??

If a section was occupied, but the train was shunted into the goods yard and the points reset to the main line, it is now no longer occupied. Where do you put the detector that detects this?

Track detection circuits are not the be-all and end-all: you need to be aware of conflicting movements signalled across diamond crossings, etc.

It was the frame from their "Jinty" LMS 0-6-0t . The "08" appeared about

Greg.P.

More detectors - even more logic. Alternatively, remove the goods yard!

My hidden sidings have both - track detection to tell me/the computer that the train is there and position detectors for precise position and clearance.

Regards, Greg.P.

It is if you use a cheap laserpointer as the light source and zig-zag the path over the tracks. This is for hidden staging tracks, though... unless you don't mind red spots on your equipment...

=>I was refering to the socket and plug for installing decoders in locos. =>

=>I've written to Lenz, NCE and MR about decoders to suit DC operation, but received no =>response - oh well, obviously they're still busy with DCC production.

Atlas's decoder is "dual mode": move a jumper to switch DC DCC. Digital Plus/Lenz decoders have "autiomatic DC conversion", which can be deactivated. Both above permit a DCC locomotive to run on plain analog DC.

All DCC systems place a high frequency AC current on the track for the signals (the track in fact becomes a network cable). Power for the locomotive is 16-18V AC, which is rectified by the decoder.

AFAIK, you can't run DC and DCC on the same layout.

Wolf Kirchmeir ................................. If you didn't want to go to Chicago, why did you get on this train? (Garrison Keillor)

In article , Wolf Kirchmeir wrote: (snipped)

ZTC and Lenz and LGB decoders have 'automatic dc changeover mode' unless specifically disabled by the user in recoding CV29. SOME but not all ZTC decoders will ALSO switch to Zero-1 mode if they detect that data pattern on the track.

The track power is effectively a constant voltage amplitude ; but its polarity is changed at the data-rate (ie it is the data carrier) as you suggest (shaped to limit high frequencies), however, re below.....

a/ Obviously a sectionalised ('cab control') layout can use both dc and dcc sections b/ it is an operating feature that a dcc loco can pass from a dcc to a dc area. ( the decoder will switch back to 'dc mode' ). This is an early method of automatically braking a loco at a stop signal.

(There is also a system of applying breaking using a dc-offset to the waveform which is recognised by some decoders!)

C/ On ANY dcc layout, it is possible to operate ONE unconverted (ie dc) locomotive - code is loco 0: (This mode has to be specifically enabled on the LGB MTS) IN THIS MODE, the data has a modified number of zeroes and ones sent, over and above that required to talk to the dcc locomotives, so that the AVERAGE VOLTAGE present on the track is no longer zero: as a result, the unmodified loco (which was probably singing merrily to itself 8-) ) will move under control in the required direction. (It is not a preferred method, but may be the only option with some locos or for a quick test prior to installing a decoder in a new loco).

It should be noted however, that the 'dc mode' of a dcc decoder is NOT THE SAME AS HAVING NO DECODER- ie a steady-dc, not pulsed output should be applied to the track )The decoder may well convert it to pulse-width drive internally)

Phil

Snipped

The ZTC 511 controller can be converted back to a pure DC controller with 4 key depressions which makes it very useful for running-in or testing locos without decoders fitted. (A similar procedure converts it to Hornby Zero-1 mode) Obviously other locos have to be isolated or removed but I find this a lot quicker and easier than physically disconnecting the ZTC unit and connecting up the old H & M.

As far as I am aware, this is the only DCC system with this feature.

Dave W.

Does this change the operating mode or bypass the decoder?

I don't use "plain analogue DC" - variable voltage PWM plus 30 kHz AC for lighting. (pulse voltages over 15v turn on coach lighting)

You can - horrible stretching of one polarity of zeros so that the 20 odd volts becomes biased to one polarity or the other. Your DC motor still has to cope with 20 volts of disipation while operating at 0-12 volts. I fried one motor that way! The frequency is

Regards, Greg.P.

In message , Wolf Kirchmeir writes

Oh yes you can. You use switches on the control panel and they switch each section to DCC one way and DC the other. So DCC becomes just another controller on a multi-controller system.

=>> Atlas's decoder is "dual mode": move a jumper to switch DC DCC. =>

=>Does this change the operating mode or bypass the decoder?

I don't know, but since jumpers are involved, I suspect it bypasses the decoder. Atlas claims that its dual mode decoder prevents the "higher speeds" seen when locomotives equipped with other decoders are set to DC mode -- that suggests bypass to me.

AFAIK, your particular power system would be incompatible with DCC. Any form of pulsed DC is seen as AC power current by the decoder (the power current is plain old 50/60Hz AC @ 16-20V) What's more, decoders supply PWM DC to the motor. However, at least one mfr is claiming their decoder supplies continuous, voltage regulated DC. Can't lay my hands on the advt at the moment.

And compared to 60Hz, 4.5 - 9KHz is high frequency, IMO - it's high enough to cause radio interference, anyhow.

Wolf Kirchmeir ................................. If you didn't want to go to Chicago, why did you get on this train? (Garrison Keillor)

=>In message , =>Wolf Kirchmeir writes =>>AFAIK, you can't run DC and DCC on the same layout. =>

=>Oh yes you can. You use switches on the control panel and they switch =>each section to DCC one way and DC the other. So DCC becomes just =>another controller on a multi-controller system.

Granted, and sorry for poor expression on my part. I meant, DC and DCC simultaneously, and in the same block, and should have said so. That AFAIK can't be one.

Wolf Kirchmeir ................................. If you didn't want to go to Chicago, why did you get on this train? (Garrison Keillor)