PR S 47114

Question 1

what is inspection and testing for

Answer 1

to ensure the installation is
-physically and functionally in accordance with design.
-failsafe

Question 2

Minimum insulation values for brand new cables

Answer 2

60 Mega ohm/ kilometre - core to core/core to earth
5 Mega ohm/ kilometre - sheath to earth

Question 3

Preference for testing circuits

Answer 3

testing as a complete circuit

Question 4

What test is done first Insulation resistance or continuity

Answer 4

continuity is conducted first to ensure the correct wire is being tested and terminated correctly

Question 5

How do you prove the integrity of the test earth

Answer 5

by connecting the IR tester to one end of the cable and to the test earth, and connecting the other end to a remote earth.

Question 6

How to conduct a bell continuity test

Answer 6

remove fuse and negative pin
remove all relays
bell each wire individually from both ends
follow series paths before doing parallel paths
conduct a wire count at the same time

Question 7

what is usually carried out with a continuity test

Answer 7

a wire count

Question 8

when is the null count conducted and what is its purpose

Answer 8

when the bell continuity and wire count has been completed.
to find any rouge connnections

Question 9

what is the purpose of the circuit function test

Answer 9

to verify that fuses, links and controlling devices are effective in controlling the circuit function

Question 10

what is the superior version of a circuit function test and why

Answer 10

a strap and function test. it proves the specific contacts of controlling devices in the circuit

Question 11

requirements of a strap for strap and function testing

Answer 11

450mm minimum length
brightly coloured preferably orange
registered and labelled in sets
kept in a locked box

Question 12

What are the exceptions to conducting an out of correspondence check on points

Answer 12

when there are separate inputs for each end in CBI installations
where the points are physically connected mechanically.

Question 13

Communication protocols for testing

Answer 13

contacts - front or back, open or closed
relays - up or down
points - LH switch open, RH switch closed and vice versa
trainstops - up or down
signals - name and colour over colour, trainstop up or down
rail vehicle detection - occupied, clear
ask non leading questions, be clear and confirm message