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