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ABC-1
2. Operation overview
The ABC (Automatic Break Control) method is based on the fact that
the ABC brake module reduces either the positive or the negative part of the digital voltage
for the braking section and thus generates an asymmetrical track voltage and
the locomotive decoders detect this asymmetrical track voltage when entering an ABC
braking section and thereupon automatically reduce the driving speed with the set braking
deceleration or the set braking distance. By setting a constant braking distance, an exact
(signal) stop can be realised for all locomotives, regardless of the speed level with which
the locomotives enter the braking section.
The normally symmetrical
digital voltage is reduced on
one side in the braking
section by the ABC brake
module, by default on the
right rail as seen in the
direction of travel.
Symmetrical track voltage
at the normal section
Asymmetrical track voltage
at the ABC braking section
In principle, the braking section is only effective for one direction of travel at a time. When
travelling in the opposite direction, the locomotive does not react to the braking section.
While the locomotive is in the braking section,
the functions can be switched,
the CVs of the decoder can be changed by means of main track programming (PoM),
the direction of travel of the locomotive can be changed and thus the locomotive can be
shunted or driven out of the braking section in the opposite direction.
As soon as the braking distance is released or the locomotive leaves the braking section, it
accelerates with the set starting deceleration up to the set speed level. No short-circuits occur
when driving over the separation point between the normal section and the ABC braking
section.
In order to be able to use the ABC braking method, the booster must provide an output
voltage at the track output that is as symmetrical as possible. When using boosters that do not
provide a symmetrical voltage at the output due to their design, the locomotive decoders may
not brake reliably when entering the braking section.
Operation overview | 5
