• Build your track
  
• Connect your railroad transformer to the track
  
• connect your railroad transformer to the wall outlet
  
• Place the train on the track
  
• Rotate the speed knob on the transformer and see the train run
  
• You could also change the direction of the train running
  

 
 
Electricity, 
or "What did your Father get you for Christmas?"
Now here was a difference, depending on what your father had bought you for Christmas... Either you got a Märklin set which runs on AC (Alternating Current) at the same frequency as you household current, but stepped down to about maximum 16 volts by a transformer. Or you got something like a Fleischmann set which runs on DC (Direct Current) which was produced by the transformer (it also converted the transformed AC to DC). DC is the kind power you get out of a battery with 2 fixed poles, one marked "+" and the other marked "-". The AC current is "+ or - insensitive" at least in this context. 
  
"I got a Fleischmann, Roco or similar set..."  
On a DC layout, to reverse a loco you had to reverse the "+" and "-" to change the direction. This is why "speed zero" on DC train transformers was generally in the middle position of the transformer knob and if you turned it clockwise, the train went forward, and if you turned it counter-clockwise from the center position the train went backwards. Or there was a switch that enabled you to switch the direction. 

"I got a Märklin set..."
On a Märklin layout, this reversing method was not possible. Instead Märklin used a "device" between the motor and track current. This "device" was an electromagnetic relay. The Märklin transformers had a knob that only adjusted the speed clockwise, and you could produce a "voltage spike" about 20-24 volts by turning the transformer knob pass the "zero speed" counter-clockwise that activated the built-in relay. On some older transformers you could push the speed knob with the same result instead. This was fun and noisy... The loco lights went bright and the loco made a lot of noise or even jumped a little bit depending on how well the relay was adjusted (or not)... This voltage spike can very well be seen as a special "command" to the loco... 

Motors & running them
The good old Märklin-motor is conventionally driven by AC, which in practice means that if you run a loco forwards, lift the loco off the track and put it back on the track in the opposite direction, it will continue to run forwards. On other model railroads, with DC current & DC motors the same procedure gives you a loco that runs backwards in the direction where the nose was before. This has to do with the "+" and "-" characteristics of a DC motor and the 2-rail track. However, the good old Märklin motor can run with DC too if you feed the power to it correctly. This will be discussed later in the article series... 

"Märklin is more fun..."
As a child, this gave me more playing value than my neighbor who had a DC layout, since I could arrange head on crashes with my trains and he couldn't... This was a really important thing back then.... ;-) 

 
 
Summary of the learning issues in this chapter

• There are 2 kinds of motors, AC-driven and DC-driven. 
  
• The Märklin AC motor is really an "all current" motor can be driven by DC too. 
  
• There can be a "device" between the rail current and the motor
  
• A "command" can be given to the loco
  
  

Back to Digital for Dummies start page