Cab control through rotary switches that is not interlocked to a signaling or other safe working system results in frequent mistakes being made. Also the more cabs you need, the more difficult it becomes to wire and run. My web page gives examples of better ways to wire your manually switched DC layout.
When I used to operate an exhibition layout using DC, I would only run each train around ounce. With one rotary switch to operate the storage yard, it was easy to change trains. More interesting for the viewing public, not much interest for the layout operator.
See my web page for details of my old layout. There was plenty of operational variety.
Terry Flynn
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HO wagon weight and locomotive tractive effort estimates
One train!? It takes twenty minutes to run a train around the layout NOW THAT'S BORING!! A train will be by every twenty minutes please come back in 19 minutes!! GREAT!!
in article 44ede16f$0$15487$ snipped-for-privacy@news.adtechcomputers.com, David Nebenzahl at snipped-for-privacy@but.us.chickens wrote on 8/24/06 10:31 AM:
Yeah! We audiophiles and guitar geeks really like tubes for their warm even harmonic distortions. Will such vacuum tube DCC (VTDCC?) make the annoying address zero buzz sound better? Maybe those square wave shoulders will be rounder and closer to a sine wave for a nice smooth beep rather than a fuzz tone zzzzzzzzzz. (100% in jest...).
I have seen manually switched DC cab control layouts were the dispatcher controls the cab selection switches. That's an example of bad DC layout design in my view. On the prototype drivers do not control blocks, therefore manually switched DC layouts that do this are another poor design. However if the cab selection also operates the signals, then you have a prototype result for your action of cab selection. Operating the cab switch is now part of a safe working procedure of a signalman for example. If your layout has a dispatcher controlling turnouts, you have CTC. If you do not have track detection expecting the dispatcher to control turnouts is a layout operation design mistake. If your DC control system has detectors, then the extra to make block selection automatic for DC block control is easy to do. A low tech non computer system only requires one relay per block.
I'm sure the DCC supporters here know of the 'who has my train' DC cab control call. That's why I prefer my DC block control over DC cab control for most layouts. DC block control is more suited for large layouts compared to DC cab control and if you build your own system, you can customise it to to simulate a specific prototypes safe working procedures.
Terry Flynn
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HO wagon weight and locomotive tractive effort estimates
It has it's limitations, one limit is the different top speeds of models, especially now we have DC sound equipped models on the market. It was designed to be a quick and easy way to get trains running while construction and wiring of the final system continues. The final system will have about 10 main line walk around controllers with in cab signals (one green and one red led). No serial communication is used between the layout and PLC's. All logic is done at the PLC software level. Signaling will follow our local prototypes block system which includes 5 and 6 lamp signals. It will have a central traffic controller who will control the main line turnouts and allocation of main line controllers. It's not my design so I am not familiar with all the details though it appears to be a automatic cab selection system. I do know the layout probably has about 3 times as many blocks than I think are necessary. I am told the number of blocks will be about 100.
6 yards associated with the main line will have a control panel which will have push button route selection. These yards will have one or 2 local controllers which can be locally switched in by holding on a button on the hand controller when selecting the route in the yard. There are a number of electrical tradesmen in control of the layout wiring, so it's done by the book, every wire is identified and numbered at each terminal point, and the documentation rivals the thickest manuals that come with DCC systems. There is allot of wiring on this system compared to most alternatives, DC or DCC. The final method of DC control of the branch lines is not decided yet.
Give me a no software DC progressive block control system any day.
Terry Flynn
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HO wagon weight and locomotive tractive effort estimates
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