01/11/12- The following is AS IT WAS with analog power and DCC mixed. This page contains some very useful info if you use such a system. Today we are " 100% DCC integrated with CMRI for signals and CTC"
Prior to our big move to the UP building in 1999, the club layout was in a long narrow store in the old Pocatello Mall. Still a "modular" group, we had poor "operations" i.e. trains ran well for public display, but realistic operations were lacking. One goal of the new configuration would be to migrate toward a railroad that could be enjoyed with what we call "operations". Trains have a reason to exist and that means picking up loads from shippers and delivering to consignees.
We were using Aristo radio control with one unit for each mainline plus some stationary cabs for train makeup, and some modules had local cabs. That's pretty darn limiting, so the new configuration would include sorting, staging and holding yards and scads of electrical switches to route cab power to selected tracks and to be able to disable some locos while others were powered. Fancy graphic panels were fabricated so club members could keep their cab power routed where desired- - IT WAS A FAILURE !
It would take nearly six years before the club voted unanamously to commit to 100% DCC. In the meantime we were successful in mixing the primitive analog, now with three Aristo radio cabs, and the new DCC. Local, non-radio analog cabs gradually faded away.
For those that are mixing systems, we'll share this.
It is a well known fact that when multiple track power sources are in use whether they be analog, separately powered DCC boosters or combinations, situations will arise where two sources will sum together and damage a pricey DCC decoder. This is not a new fact and has existed in previous years in the analog world but the only risk was perhaps a burned out light bulb on the loco or coaches and it went unexplained. We were aware of this risk, having debated it publicly in DCC forums, and safely mixed the systems by insuring that the NEGATIVE terminal of every power supply, whether Analog or DCC was tied to a COMMON point. Do not confuse this with "common rail wiring"! Voltage summing is no longer possible, only voltage differentials can exist. We ran this way for six years and never harmed a single decoder or burned out a lamp!
Without going into the details, the result is this: There is a slightly higher risk of booster damage with its easily replaceable 50 cent transistors while reducing the damage risk to pricey, unrepairable decoders to zilch.
Its Feb, 2008 and we are 100% DCC. Our five boosters have been de-centralized Four are spread around the double mainline loop of about 240 feet. A booster is centered in a 60 foot section and reaches out about 30 feet each way. The fifth booster serves the staging, holding and terminal yards. The EasyDCC command station simply sends low-energy data to each booster via economical telephone type wiring. along with a sixteen gauge COMMON wire as described above. Sixteen gauge is adequate because it does not normally carry current. It's purpose is fault protection only. Each booster is mounted on a subpanel with CVP's new 120 watt DC switching power supply set at 18 volts. The DC power suppy gets its raw 120 VAC from a nearby outlet. Our CVP "three-amp" boosters can put out a tad over four Amps so there is capacity left over that can be used for accessories such as switch machines. A conventional LM317 voltage regulator will provide reduced voltage and current limiting for this use.
The sub panel with the booster for the staging yard wye and balloon track is equipped with PSX auto-reverser. All of the new sub-panels include provision for future CMRI SMINI's for signalling and CTC. Now all we need is money-
The radio receiver along with the command station is somewhere near the center of the layout. The receiver is set high inside a multi-story plastic industrial building with the antenna concealed with roof appertenances. There are no dead spots in the 3000 square feet. The cab count is up to six and we are searching for money to add more. EasyDCC is unique, with two more non-mobile cabs on the command station. We're looking at using the old Aristo's to control them.
The whole layout is a lot more fun to operate and it's not a bit unusual to have two or three trains on each mainline for open house days. The yards that were shied away from are now in use for switching and train makeup. Most of the old power routing panel switches are gone, with only a few retained for quick fault isolation when someone goes "on the ground" or to shut down a loco sound system.
Return to Pocatello Model Railroad and Historical Society home page