PR S 40006 Flashcards
Releases
what are the three types of locking in interlockings
Approach Locking, Route holding, indication locking (NI and RI)
what are types of manual releases
momentary bridging, lifting of electric locks or mechanical locks.
What can you not release
locking between conflicting signals, points and level crossings
can you provide a release for mechanical interlockings
no, authority must be granted by a signal engineering manager
Relay interlocking releases
ASLR (approach locking), Signal NI relays, points lock relays, USR (route holding relays)
Route control interlocking releases
ALSR (approach locking), Signal route normal NLR, relays, Route holding in NLR/RLR points lock relay, Route holding in route stick relays (USR)
manual release methods
Lifting of electric lock on levers, lifting of lock on release switches, false feeding relay, bridging stick contact of relay, bridging track circuit relay contact.
momentary bridge requirements
at least one end is handheld, suitable for use, can be improvised or registered for further use. must be destroyed after use if improvised.
how do you document a release
all details of the release including the assurances must be documented on and IBA NRF 003
can you use the same IBA for multiple releases
No, each release must require a new seperate IBA
what are the main two assurances required for a release.
the protecting signal is at stop with blocking facilities applied and the trainstop proved to be in the raised position.
any trains on approach to be brought to a stand and will remain so.
how many types of releases are there
13 releases
which releases require engineers approval
USR releases, Points locking releases, CBI (computer based interlocking releases)
