A journal following the history, design, construction and operation of Bernard Kempinski's O Scale model railroad depicting the U. S. Military Railroad (USMRR) Aquia-Falmouth line in 1863, and other model railroad projects.
©Bernard Kempinski All text and images, except as noted, on this blog are copyrighted by the author and may not be used without permission.

September 26, 2010

Houston, we are DCC!

Thanks to some expert help from Paul Dolkos and Mitch Oldham, the USMRR Aquia line is  now running on DCC.  I was able to get most of the wiring done from Falmouth to Aquia Landing, but that is getting ahead of the story.

Paul installed the Easy DCC command station in a
temporary spot on the benchwork until I decide where
it should go permanently.
Paul is an owner of the Easy DCC system for his HO layout, so he was able to immediately open the boxes and begin connecting the components without any delay. Well, there was one delay. It seems I had forgotten to disconnect the DC power pack from the rails.  When Paul went to fire up the DCC system, the start-up sequence was not what he normally sees on his system. After a few perplexing moments wondering why the Easy DCC was not going through its normal start up procedure, I smelled smoke. Sure enough, the DC power pack was beginning to put out a serious amount of smoke. I disconnected the smoking power pack, and the Easy DCC system fired right up. Whew! I am glad the Easy DCC didn't fry.

Mitch at the workbench installed a decoder
In the meantime, Mitch was installing a decoder in the 4-4-0 Haupt, one of my SMR Masons in the work shop. Mitch used to run a DCC business and he came prepared with all manner of cool specialized DCC diagnostic tools. He methodically disassembled the Haupt and identified pickups, grounds etc. Then he went ahead and installed a Digitrax DH123D that I had previously purchased. This is a non-sound, economy decoder. I also had a Dallee Sound System sound chip, but we decided not to install it as it is pretty large and probably would not fit in the tender or boiler.

The Haupt crossing Potomac Creek under DCC.  Note
the bright headlight.
With the decoder installed the engine ran very well. However, I don't think this decoder features back-EMF as the engine speed varies as the loco moves across the tighter curves on the layout.

The loco's headlight light is always on when DCC power is on the track and is running quite bright. That must be addressed before it burns out by adding a resistor in line with the bulb. This will require running wires from the decoder to the headlight, but it looks easy thanks to the removable smoke box, a nice feature of the SMR Masons.

We learned a lot from Mitch's surgery on the Haupt. The removable smoke box and head light assembly will simplify many of the tasks needed to add sound and controllable headlight. We decided that on this loco the best place for the sound speaker will be in the smoke stack. Again this will require wires from the tender to the engine, but it shouldn't be too hard.  We also learned that the tender trucks have a split frame, so adding a second set of pickups on the tender axles will be relatively simple. (Note the McCallum already has these wires factory installed.) I will replace the DH123D with a Soundtraxx Tsumani decoder so that sound is integrated right in the DCC decoder. In fact I need to order five of them ASAP.

Mitch took the McCallum home with him to try to find why it is shorting on curves. He plans to get one too, so this will be win-win as he gets to study the loco before he buys it. He is making the switch from HO to O Scale ACW -  Huzzah!

The Tam Valley Hex Frog Juicer on the left lights up like a
Christmas tree.  The yellow wires run to the various frogs.
The outlet strip on the right has the bus lines to the
power districts. For now they are daisy chained into one district.
After Paul and Mitch headed home, I finished running bus lines, soldering feeders and installing the Hex Frog  Juicer. Tam Valley Depot makes the Hex Frog  Juicer and it is an absolute delight to install. No more fiddling with balky Tortoises or finicky mechanical linkages underneath the benchwork. This has to be the easiest way to power frogs. I have four frogs wired to it so far and it works as advertised. Thanks Duncan!

Terminal strip to allow smaller wires to be used on the HFJ sockets.
 Another half day of wiring and two thirds of the layout will be operational. Running with wireless throttles is really a pleasure that I had nearly forgotten.

I decided to rewire the HFJ to use smaller wires than the 18 gauge into the sockets. I added a terminal strip. This acts as an intermediate between the 18 gauge wires and 24 gauge wires. The holes on the HFJ sockets are very small. Thelast two FJs power the double crossover in Falmouth.

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