Controllers For Model Trains

Over the past 100 years several methods ofreducing signal loss and in ensuring that all
controlling electric model trains have developed.components of the model train layout operated
The first and simplest method was the use a simpleproperly. All this additional equipment however added
variable transformer as introduced by Lionel in 1906to the cost, the complexity, and the maintenance for
to lower the Alternating Current [AC] voltage fromthe model train operator.
the wall to a lower, safer value and allow the user toModel train manufacturers have, over the years,
control the speed of a model electric train byintroduced different methods of applying high
changing the amount of AC power applied to thefrequency signals to the model train track to increase
track. In the 1920's, Lionel included remote controlthe remote control capabilities including independent
reversing switches to allow the user to control thetrain control which means that the operator can
direction of the model train.control the speed, direction and features of a number
When Direct Current [DC] powered trains withof different engines all on the same powered track
permanent magnet motors were introduced, asection. With most DC and AC systems however,
different standard was developed for most two railthe biggest problem is that there are only a limited
train tracks where the direction of trains werenumber of remote control signals possible and their
controlled by the polarity of the DC track powerapplication is slow 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 ofcontrol signals to carry digital signals to decoders in
applying DC on top of the AC track voltage to turnthe engine for digital command control of locomotives
on and off an on-board whistle by remote control.and other accessories.
This concept of high frequency transmission wasDigital Command Control (DCC) is a method of
introduced in the Lionel Electronic Train Control. Thiscontrolling individual engines, rail cars and accessories
system supplied ten different signals that wouldby transmitting digital remote control signals down
control ten different remote control effects. Thethe track to on-board digital receivers and decoders
different high frequency signals were superimposedin the locomotives, wagons and other rolling stock
on the standard AC power when selected buttonsand accessories.
were pressed at the control center. Each remoteDCC has been around since the 1970's but had not
engine or rail car was equipped with a receiver unitreceived wide acceptance because of the limited
that was tuned to the individual frequencies. Whentechnology at the time and the difficulty and
the correct high frequency signal was transmitted,expense of installing receivers in each engine. With
the corresponding receiver would toggle or turn-ondevelopments in digital technology these problems
some remote effect.have diminished and over the last ten to fifteen
These high frequency signals increase the ability toyears major model train manufacturers have
remotely control various effects but they had otherproduced several different versions of DCC. So many
problems. Transmission losses were usually high and itthat unfortunately customers have been confused
was critically important to keep the track, the trackabout which system is best.
joints and the wheels of the receiving car orFortunately, in recent times, the National Model
locomotive extremely clean. However extra feederRailroad Association [NMRA] has established a
wires to different parts of the track were used topreferred method of transmitting and receiving digital
prevent signal losses and placing capacitors acrosstransmissions on model train layouts, based on the
the track joints and adding inductors at the powerLenz system developed in Germany and this is
supply and on each accessory being used assisted inrecognized as the accepted standard for DCC.