Controllers For Model Trains

the past 100 years several methods of controlling				loss and in ensuring that all components of the
electric model trains have developed.				model train layout operated properly. All this
The first and simplest method was the use a				additional equipment however added to the cost,
simple variable transformer as introduced by				the complexity, and the maintenance for the
Lionel in 1906 to lower the Alternating Current				model train operator.
[AC] voltage from the wall to a lower, safer value				Model train manufacturers have, over the years,
and allow the user to control the speed of a				introduced different methods of applying high
model electric train by changing the amount of				frequency signals to the model train track to
AC power applied to the track. In the 1920's,				increase the remote control capabilities including
Lionel included remote control reversing switches				independent train control which means that the
to allow the user to control the direction of the				operator can control the speed, direction and
model train.				features of a number of different engines all on
When Direct Current [DC] powered trains with				the same powered track section. With most DC
permanent magnet motors were introduced, a				and AC systems however, the biggest problem is
different standard was developed for most two				that there are only a limited number of remote
rail train tracks where the direction of trains were				control signals possible and their application is slow
controlled by the polarity of the DC track power				by modern digital standards.
applied to the track.				The application of digital technology uses remote
In the late 1940's Lionel added a new concept of				control signals to carry digital signals to decoders
applying DC on top of the AC track voltage to				in the engine for digital command control of
turn on and off an on-board whistle by remote				locomotives and other accessories.
control. This concept of high frequency				Digital Command Control (DCC) is a method of
transmission was introduced in the Lionel Electronic				controlling individual engines, rail cars and
Train Control. This system supplied ten different				accessories by transmitting digital remote control
signals that would control ten different remote				signals down the track to on-board digital
control effects. The different high frequency				receivers and decoders in the locomotives,
signals were superimposed on the standard AC				wagons and other rolling stock and accessories.
power when selected buttons were pressed at				DCC has been around since the 1970's but had
the control center. Each remote engine or rail car				not received wide acceptance because of the
was equipped with a receiver unit that was tuned				limited technology at the time and the difficulty
to the individual frequencies. When the correct				and expense of installing receivers in each engine.
high frequency signal was transmitted, the				With developments in digital technology these
corresponding receiver would toggle or turn-on				problems have diminished and over the last ten to
some remote effect.				fifteen years major model train manufacturers
These high frequency signals increase the ability				have produced several different versions of DCC.
to remotely control various effects but they had				So many that unfortunately customers have
other problems. Transmission losses were usually				been confused about which system is best.
high and it was critically important to keep the				Fortunately, in recent times, the National Model
track, the track joints and the wheels of the				Railroad Association [NMRA] has established a
receiving car or locomotive extremely clean.				preferred method of transmitting and receiving
However extra feeder wires to different parts of				digital transmissions on model train layouts, based
the track were used to prevent signal losses and				on the Lenz system developed in Germany and
placing capacitors across the track joints and				this is recognized as the accepted standard for
adding inductors at the power supply and on each				DCC.
accessory being used assisted in reducing signal