Occupation Detection using a |:| Marklin Track
Electrical 101 on |:| Track
the Marklin track uses 3 electrical connections. The 2 tracks itself
and a third one in the middle. This gets a symmetrical track which
avoids shortcuts on loops. The 2 tracks are usually connected. Also all
locos and cars have electrically connecting axles. This is the reason
that all axles need to be changed when a marklin car should be operated
on DC track.
STP monitors all sections on occupation, this is done via the MX9
section modules. To detect all cars it is necessary to have some little
load on the track. In DC world this is done via resistors on axles. The
|:| track offers a simpler solution.
Just separate the two track sides. One side is left to the track
power supply. The other side is insulated the same way as the middle
one. Then connect a resistor of about 5kohms between the middle one and
that rail. If a car is on the track left, for example a lost one, the
axle will connect the 2 tracks. so a small current runs from the middle
over the resistor to the insulated track, further on via the axle to the
other track. The MX9 is able to sense a small current and the occupation
is securely detected.