1. Ph.D. Candidate, School of Engineering, College of Engineering and Physical Sciences, Univ. of Birmingham, Edgbaston B15 2TT, UK (corresponding author). ORCID: .
2. Reader in Infrastructure Asset Management, School of Engineering, College of Engineering and Physical Sciences, Univ. of Birmingham, Edgbaston B15 2TT, UK. ORCID: .
3. Honorary Senior Research Fellow, School of Engineering, College of Engineering and Physical Sciences, Univ. of Birmingham, Edgbaston B15 2TT, UK. ORCID: .
4. Lecturer in Infrastructure Asset Management, School of Engineering, College of Engineering and Physical Sciences, Univ. of Birmingham, Edgbaston B15 2TT, UK. ORCID: .
5. Principal Engineer, Network Rail, Elder Gate, Milton Keynes MK9 1EN, UK.