EP circuits and points Flashcards
What is the purpose of the auto drain/filter
It filters moisture out from the mains air when it enters into the a unit and drains it automatically
Label the 10 parts of an A unit
Label the 10 parts of signal branch points
When correspondence/out of correspondence testing what additional action must be taken for and why
- A units
-Facing signal branch points
a. The pressure switches on the detection side must be bridged in accordance with PR S 40002. This is to ensure any error when testing is identified
b. For correspondence testing, the indication box contacts and plunger lock inhibit the points when opened. This is because these contacts, are included in the detection circuit and must be able to effectively make and break detection
what is the purpose of the pressure switches on an A unit
What are the solenoid valves N/R used for in the A unit
What circuits are broken by the removal of the ESML handle
What is the purpose of the slide valves on an A unit
What is the purpose of the spool valve on A units
What is the purpose of the Economical movement
What points don’t use a plunger lock
claw lock, spherolock and points with internal locking such as m3a, nippon.
What is the purpose of the plunger lock.
What is the difference between pilot and mains air
What is Heavy detection
Heavy detection is where the adjustment of detection is above the specified range allowing the switch to open an undesirable amount before detection is lost leading to the potential to derail a train before the interlocking can prevent it.
What is Light detection
Light detection is where the adjustment of detection is below the specified range allowing detection to be lost even while the switch is effectively against the stock rail due to small movements/vibrations in the rail under passage of a train.
