You're talking about the obsolete TBMs that were used on the Spadina subway extension, right?  And the Chinese have better, more efficient ones.  Thanks for the info as I didn't know about that before today.
If I understand your argument, a Chinese-owned Aecon could use Chinese TBMs to reduce the cost of building subways.  Ok. What I don't understand, is why a Canadian-owned Aecon, or an Elbonian-owned Aecon for that matter, couldn't buy the same efficient TBMs?   Hopefully, you're not saying that we need special channels in order to buy the latest technology from the Chinese.