The TBMs from Sheppard Line 4 were sold to Moscow for $2.5 million each for their subway. If they can be shipped and used halfway across the world, I wonder what geological differences would necessitate different TBMs a mere 25 to 30 km away. If refurbishment was an issue, it would've been an issue for Moscow as well but they made it work somehow.
TBMs have a design life of 20 kms and most of our projects are well below that, so we buy top of the line brand new TBMs and sell them for pennies on the dollar after using them for around 20% to 30% of their design life.
These aren't cheap purchases for Toronto, ranging around $20 million per TBMs these days. Why do we not buy used? Why can't we reuse them between our projects?
More info can be found here:
National Post Article
And here:
Another article
The second article mentions newer TBMs have the potential to be faster but this is grasping at straws. The TBMs of the different projects all tunnel at relatively same speeds for the past 20 years.