2018 Mock Exam Paper for mod 1 & 7

[PJW]

Selected (and sometimes slightly amended) past questions for a composite mod 1 / 7 exam paper which is included under the mod 1 heading.

There were 5 candidates,

• 3 of whom opted for a mod 1 question (posted in that thread) and
  
• 2 of whom opted for a mod 7 question (posted below)
  

Please feel free to post feedback for them

[PJW]

Candidate 3's attempt

Question B6
Describe three distinctly different  ways in which human error can affect the integrity of signalling or telecommunication systems, and hence influence the safety of the railway.              [9 marks]
For each example above, describe how procedures, training and technology can each be used to minimise the risk of human error leading to an unsafe event.                                                                   [16 marks]

[PJW]

Candidate 5's attempt.

Question B1
 
A piece of equipment is used to prevent an unsafe action being implemented on a railway. It fails, on average, 80% right side and 20% wrong side, with a mean time between all failures of 10,000 hours. It has a mean time to repair of ten hours.
 
Three identical sets of this equipment are configured in a two-out-of-three voting system. The voting activity has a response time of one second. If the failure rate of the voting subsystem is ignored, calculate:

1. how often a technician is required to attend to repair the triplicated system;
   
2. the proportion of time that, through multiple failure, the system unnecessarily prevents operation of the railway;
   
3. the mean time of the system being in a state where it would not prevent an unsafe action.              [25 Marks]