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Turing Trains


computational train track layouts


Count Up/Down

The Count register (C) is incremented, one step at a time, until its value is a maximum '111'. It is then decremented back down to zero '000'. The Count register ramps up and down in a continuous cycle.

The overflow line from each Counter sends the train to the other function to reverse the Count process.

This circuit comprises a Count Up and a Count Down function. No need to clear points, just run!

Up/Down Counter
ramp up down layout
Click layout to pause/run train Click points to switch 0/1 Click start circle to reset train/points
lazy point Lazy points switch between upper 0 or lower 1 branch lines
Trains arriving on a branch line switch the point to that line
sprung point Sprung points allow branch line trains to join the main line
All main line trains go straight ahead and never 'branch off'


  1. Start train running from station.
  2. The Count register will increase (count up) and then decrease (count down), one step at a time.

Linked Functions

Note that the points in the two registers are linked together vertically. Linking points allows data to be shared between the Count Up and the Count Down functions.



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