What is the longest train line you have worked on?

Question: What is the longest train line you have worked on?
- Keywords:
  train
Asked by Esme_1xx to Andrew, Angela, Eleanor, Emma, Withdrawn on 8 Mar 2016. This question was also asked by Archie wwe beast 619.
- Andrew Pidgeon answered on 8 Mar 2016:
  
  Sadly I’ve never worked on one really.
- Eleanor Sherwen answered on 8 Mar 2016:
  
  I’ve helped my brother with some model trains. So maybe 2 metres. You want to ask @Emma this one!

Question: What is the longest train line you have worked on?