introduction to reliability centred maintenance · 2020-03-09 · introduction to reliability...

Introduction to Reliability Centred Maintenance

Keith Ashington

M.Eng CM.EngNZ C.Eng M.ICE

Summary

• Background

• What is RCM2?

• The RCM2 process

• Application to track assets

• Benefits

Background

Initial assumptions

• Every aircraft has a specific ‘life’

• Every major component has a specific ‘life’

• Servicing carried out just before ‘life’ reached

• Life can be predicted / defined

• Reducing service life increases reliability

Study findings

What is RCM2?

“A process used to determine what must be done to ensure that any physical asset

continues to do what is users want it to do in its present operating context”

Further publications

RCM2 in the UK rail network

• NR/L2/SIG/10662

• NR/L2/MTC/10662

The RCM2 Process

FMECA+

Workshop

RCM2

Facilitator

Engineering Supervisor

Operative

External specialist

Operator

Operations Supervisor

Operating Context

Stage 1 - Function

• “What are the functions and associated performance standards of the asset in its present operating context?”o “To…

o …Verb…

o …Noun…

o …Performance Standard”

• Primary Function

• Secondary function

Stage 2 - Functional Failure

• In what ways does it fail to fulfil its functions?

Stage 3 - Failure modes

• What causes each functional failure?

Stage 3 - Failure modes

Stage 4 - Failure effects

• What happens when each failure occurs?

• Identifies potential failure points

• Defect may not become observable

100% Capability

Starts to degrade

Defect becomes

observable

Further degradation

Failure

Stage 5 - Failure Consequences

• Hidden Consequence • Safety / Environmental consequence

Stage 5 - Failure Consequences

• Operational • Non-operational

Stage 6 - On-condition tasks

• Predictive / Preventative

• Defects lead to Faults

o P = potential for failure identified (Defect)

o F = failure identified (Fault)

o P-F = inspection interval + rectification period

Typical on-condition tasks

KiwiRail example – track geometry

• Rectification periodso P4 = 13 weeks

o P3 = 2 weeks

o P2 = 3 days

o P1 = 1 days

o U1 = FAIL

• BUT P2 requires TSR, so failure.

• Very little time to plan rectification

• Inspection Intervalso Class A(M) = 17 weeks

o Class A(NM) = 26 weeks

o Class B = 35 weeks

o Class C = 52 weeks

KiwiRail P-F Intervals

P4 P3 P2 P1 U1

Class A(M) 30 weeks 19 weeks 17.3 weeks 17.1 weeks 17.0 weeks

Class A(NM) 39 weeks 28 weeks 26.3 weeks 26.1 weeks 26 weeks

Class B 48 weeks 37 weeks 35.3 weeks 35.1 weeks 35 weeks

Class C 65 weeks 54 weeks 52.3 weeks 52.1 weeks 52 weeks

• P-F Interval = inspection interval + rectification period

• More time needed to rectify

o Reduce inspection interval

o Find P5

Stage 7 - Scheduled tasks

• On-condition tasks not possible

• Still a risk of failure

• Discard

• Restoration

Stage 8 - Default Actions

• Hidden Consequenceso Failure finding tasks

• Safety / Environmental consequenceso Compulsory re-design

• Operational / Non-operationalo Desirable re-design

o Do nothing

Implementation

• Improved Maintenance Regime

o On-condition Tasks

o Scheduled Tasks

o Re-designs

o Failure finding tasks

Improved Maintenance

Regime

Professional Head Approval

Implementation

Review

RCM2 analysis of track assets

• Exeter - Barnstaple

• Bristol - Exeter

• Euston – Rugby

• Bletchley – Bedford

• Paddington -Heathrow

• Etc

RCM2 analysis - findings

• Consequences o Hidden – Low (Buffer stops, guard rails)

o Safety / environmental - high (Wrong side failures)

o Operational – low (Right side failure, IBJ)

o Non-operational – low (Wheel squeal)

• On-condition taskso Already in place

o Changes in frequency

o Changes in rectification periods

Changes to on-condition tasks

• All inspections intervals and periods justified

Inspection Change

Patrolling Removed

SM(T) Inspections Replaced with verifications

TME Inspections Maintained (Assurance)

Track Geometry recording

Non-mandated AL faults became mandated

Ultrasonic inspections Non-mandated faults became mandated, all suspects verified

Structure Gauging No change (ORR mandated)

Grinding No change

Lubrication No change

Impact on traditional track

• On condition taskso Small P-F

o Worth doing?

• scheduled restorationso Screw tightening

o Lubrication

o Joint adjustment

o Fastening maintenance

• Default actionso Redesign (Modern track)

• Operating context

o Low tonnage

o Low speed

o Low spend!

Impact on modern track

• On-condition taskso Automated

o Fewer visual inspections

• Scheduled Restorationso Grinding

o Rail lubrication

• Scheduled Discardso Re-padding

• Default actionso Turnout redesigns

Results of RCM2 analysis

• Greater reliance on automated systems

• Targeted track patrolling / verifications

• Maintenance backlog reduced

• Opex reduction

• Risk reduction

Do we need to patrol at all?

• Safety risk on site

• Safety risk travelling to site

• Age / fitness

What can be achieved?

Thank you!

Questions?

Keith Ashington CM.EngNZ, C.Eng M.ICE