|Back of the machine:
The 504C Line-Coding (LC) unit is at the top,
with the office P-4 relay mounted next to it.
Below it are two storage cabinets for the 9 stations.
These were all re-wired from some KCS cabinets.
There are Amp CPC connectors on all wiring to
the cabinets, in case they need to be removed.
|Field Location for Blair Interlocking:
504C Line-Code-Storage (LCS) unit upper left, pup in the middle, and P-4 field line relay right. Stations are 234 and 235 - a PLC is mounted below.
Some shelf relays are provided to control some of the signals that I have outside.
|Office Code Unit &
P-4 Office Line Relay
|Field Code Unit &|
P-4 Field Line Relay
|Field Storage Unit or "Pup"
This allows another station of 7 controls and 7 indications
to share the same field code unit (pictured above).
Click here to listen to this equipment operating
The first set of clicks (16 counts) is the office unit sending out a control request.
The second set of clicks (16 more) is the field unit reporting an indication back to the office.
|504C Test Set
This is used to test
office and field
units to make sure
they are functioning
All station, control,
and indication cycles
can be tested, along
with voltage and