User Manual

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H. APPROACH MODE OPERATION
On many prototype railroads, signals remain unlit until a train is approaching. The Atlas Model
RR Signal System has the capability to duplicate this operation. In the diagram found to the right,
Signal #1, which is connected to Block #2, will remain dark until a train enters Block #1. The
signal will then light for the approaching train.
For stand-alone signal operation, a wire from an insulated rail section in the block ahead of the
signal must be connected to the TO TRK terminal on the BDB. A wire is then run from the DET
terminal of the BDB to the J6 terminal strip “AIN” connection on the SCB. The wire must be
screwed to this connection. Also, a wire from the insulated rail section behind the signal must
be connected, through a BDB, to the YIN terminal of the J5 strip on the SCB. The enclosed
jumper plug must be installed across the JP1 pins, (see page 19 for ‘Setting the Jumper Plugs’).
The signal will now follow the pattern of "Off – Green – Red – Off". If a train is occupying Block
#2 and another train enters Block #1, the signal will be red. Similarly, if a train is occupying
Block #3 and another enters Block #1, the signal will have a yellow aspect.
If you are using a fully-integrated wiring scheme, and all of the signals are connected with the
Atlas Model Signal Cables, approach lighting is very easy. Only the jumper plugs across the JP1
pins on each of the SCBs are required. Separate wires and detectors for the J6 and YIN termi-
nals are not necessary.
APPROACH MODE