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 |
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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 correctly. All station, control, and indication cycles can be tested, along with voltage and timing tests. |