"'The programme is very ambitious, and there is a clear deadline that nobody is going to be able to miss. You have got some very complex engineering, as you effectively have three very big networks.'
'That is going to affect the way the work is procured almost certainly, because we have heard that they need to tender these contracts almost immediately. It is all coming up very quickly,' said [Hyder Consulting regional rail director Geoff] Leffek.
Another major challenge is logistics, as 'the vast majority of labour and material will need to be imported'."
The city's central business district is expected to be the most difficult area to build, and Leffek says completing the system in time for the event will be a challenge.