All --
I have been quite amused by all this chit-chat about how easy it is to convert
to DCC, and how turnouts don't have to be modified, etc., etc. I have no doubt
that those of you who have actually converted to DCC and expressed your
opinions speak the truth for your particular situations. But I have just
finished converting my layout to DCC and my experience is quite different.
I decided to convert because I often forgot how to run my railroad while
entertaining guests. Let me explain:
My layout is 12'x 43'. Its primary route is a double-track main line with one
staging yard serving both ends. There are also two single-track branches, both
served by second staging yard. I used two independent Aristo-Craft wireless
throttles to control each of the mains (one eastbound, one westbound). The
circuitry was such that the two could not become confused, and the two
throttles each had different frequencies.
Most junctions (yards, spurs) were wired such that the auxiliary contacts on
the switch machines routed current from one of the mainlines (either eastbound
or westbound) according to which way the turnouts were thrown. But there was
one section that required a rotary switch because switch-machine contacts were
not sufficient. This is where a branch line joins the eastbound main and must
nevertheless accommodate westbound trains coming off the branch prior to taking
the crossover some five feet west. OK. So I mastered that.
One of the two branch lines could have its power manually switched to a
separate power supply so the branch could be operated independently. This
created a situation in the two branch lines' shared staging yard that required
a selector switch for each of the four staging tracks to draw power from either
one branch or the other. This was because power from one would always be one
of the two wireless throttles, whereas power from the other could be any of
three alternates: The same wireless throttle, the other wireless throttle, or
the separate branch line power supply. OK. So I mastered that -- Sort of.
These two "features," taken together, sometimes made my life as a train
engineer difficult. But I had to face yet another electrical switching problem
when it became clear that a portion of one of my passenger-only westbound
tracks had to be converted to an industrial siding while the other joint-use
passenger/freight eastbound main had to handle westbound passenger trains.
(Got that?) That change would have required another rotary switch. Not only
that -- An operator would have to walk as much as 20' from his train to flip
the rotary switch, then walk back to his train. This I could not face. While
I had no doubt that I could figure out the circuitry, I had every doubt that I
could remember to perform all of these electrical-switching tasks properly
while operating my trains.
Now keep in mind that, except for the main line per se, all of my power was
routed/cascaded through sequential contacts on switch machines, in some places
as many as eight of these. There is tremendous potential for current loss
through all these contacts. It didn't matter as long as one throttle
controlled one locomotive, but with DCC, I've got to have five amps and 12
volts everywhere all the time. So the route-controlled power scheme had to go.
I could not simply disconnect my conventional power, replace it with a DCC
command station, and expect things to work.
In theory the rewiring is simple. Just strip out all the old wiring, install
12-gauge twisted-pair bus wires, drop feeders every six feet or so, and make
sure that all the turnout frogs are powered directly from the bus via just one
set of switch-machine contacts. But let me tell you, even if it were just this
simple, there is ample opportunity for error. I realized at some point that I
needed to have an ammeter and a voltmeter connected across the two bus wires at
all times (with power applied) as I was making all of these new connections.
With literally hundreds of new soldered wire connections, one WILL make an
occasional error.
The real fun began when I had to rewire complex trackage. My terminal throat
is a multi-track wye with two three-way turnouts, a simple crossing, and a
crossing that cuts right across a turnout. In the old wiring scheme I used
multiple switch-machine contacts to assure power in every rail segment
according to the route selected. The new scheme required complete re-thinking
of the throat wiring. I wound up with two auto-reverse units operating more or
less in sync to power the crossings,
There were other problem areas, but I won't go into them.
I am fortunate to have had the help of friend Roger Nulton, who did more
than his share of my under-the-layout soldering. He also lent me one
of his decoder-equipped locomotives to check out my rewiring.
Once the layout was short-free, I ran Roger's loco everywhere. Of course there
were some residual errors -- two types: Lack of power in certain rail
segments, and inconsistent power, like frogs drawing from the wrong bus wire.
For these I used little pieces of masking tape encoded with an "S" (for short
circuit) or a "D" (for dead), stuck on particular rail segments to tell me
what/how/where to trouble-shoot. As I worked off each one I removed the little
piece of tape.
I had also divided the layout up into four separate power districts. This
really helped -- I was never faced with tracing circuit problems throughout the
entire layout.
The end result is that there is now a lot less wire under my layout. The wire
I stripped out fills a large cardboard box. The surplussed electrical gadgets
(toggles, meters, throttles, etc.) fill another box.
A final note relating to benchwork design: My average track height is 58"
above the floor. Additionally, my main terminal area is hinged to tilt up,
much like the lid of a grand piano. These features, together with a
secretary's chair on five casters, saved two old men from possibly severe
strains and cramps while doing the rewiring task. And we wore denim pants,
which are impervious to drops of molten solder. Oh -- a hat or a huge mop of
hair really helps cut down on head dings. Guess which one of us depended on
which mode of protection?
Dick Karnes
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