DC TC FAULT (SOWC) FLOWCHART v1.3
THE FAILURE IS NOT A WSF. FOLLOW WSF TEST PLAN IF PROVEN TO BE A GENUINE WSF. DO NOT FOLLOW THIS GUIDE.
Main Decision
CAN SIGNALLER CLEAR SIGNAL OVER THE FAILED TRACK CIRCUIT?
YES → INDICATION ONLY FAULT
→ CHECK TKR CIRCUIT IN SIGNALBOX
→ CHECK TKR CIRCUIT IN SIGNALBOX
NO → ACTUAL TRACK FAULT OR TPR FAULT
→ GO TO FEED END OR RELAY END
→ GO TO FEED END OR RELAY END
Feed End Checks
CHECK VOLTAGE ON RAILS (METER ON DC)
NO VOLTAGE → PARTIAL SHORT © → SEE PAGE A
PARTIAL/LOW → TC PROBABLY OK ©
HIGHER THAN NORMAL → TPR FAULT
FULL VOLTAGE → CHECK TR RELAY
Relay End Checks
CHECK TR RELAY IF AT LOC FIRST
CHECK VOLTAGE IF AT TRACK ENDS FIRST
FULL VOLTAGE →
- CHECK TR CONTACTS
- HIGH RESISTANCE → REPLACE RELAY ©
- CONTACTS OK → CHECK NEXT TPR (TIPR)
PARTIAL VOLTAGE →
- CHECK LOC & RAIL CONNECTIONS
- IF ALL OK → TPR FAULT
CHECK TPR FEED FUSE
- BLOWN → CHECK FOR BROKEN RAIL & CONNECTIONS
- OK → CHECK CURRENT DRAWN & REPLACE FUSE
From Page One (A)
CHECK OUTPUT VOLTAGE ON TFU
- OUTPUT OK
- NO VOLTAGE →
- WIRE OFF BETWEEN TFU & RAILS
- TFU SUPPLY FUSE BLOWN
- CHECK CURRENT & REPLACE FUSE
- FULLY TEST TC ©
From Page One (B)
WALK TRACK, CHECK VOLTAGE EVERY 10m
- CHECK PWAY INSULATIONS
- CHECK IBJs
- NOTHING FOUND → CONTINUE
- INSULATIONS/IBJs FAIL →
- TEST WITH K9
- FOLLOW R.O.A CHECKS
- PWAY TO REPAIR
From Page One (C)
TPR B50 FUSE BLOWN OR WIRE OFF
- CHECK & RECTIFY
- NO NEED TO TREAT TC AS FAILURE
From Page One (D)
FAULT IN TPR CIRCUIT IN FURTHER LOCS
- CHECK ALL TPRs
- CHECK 50v SUPPLY (45–55v)
- IF HIGH → POSSIBLE DIS BETWEEN LOCS
- RELAYS WON’T ENERGISE BELOW 37v
- CHECK PREVIOUS RELAY CONTACTS
- TEST CABLE CONTINUITY IF NEEDED
- IF TC CLEARS → CONTINUE INVESTIGATION