To correct your statement, Bombardier caused the vehicle issue, thus they caused the delay.
If you really want to get technical, it's entirely a Metrolinx caused issue at the time they wrote/signed two different contracts with zero consideration as to how they interact until a couple years after they signed them.
The penalties Metrolinx agreed to pay on Eglinton for non-delivery of vehicles (as a subcontractor responsible for that task) is high. The penalties they wrote into the Bombardier agreement for non-delivery of vehicles is low. The gap between these 2 penalty fees is about $500k per day. Keep in mind, Metrolinx agreed to Eglinton penalties in 2015; Bombarder was already quite behind on the TTC order.
In short, Metrolinx took on financial responsibility for actions of a 3rd party. That was a really poor judgment call by the Metrolinx (or IO) legal department. Bombardier delivery delays wouldn't be an issue if Bombardier was paying the penalty fees. Metrolinx has zero interest in opening Eglinton on time; they're trying to avoid the $182M/year penalty fees when they're late delivering their piece of it.
And none of that has anything to do with Finch (or Hurontario). Metrolinx is screwing over Finch trying to fix their fairly significant Eglinton fuckup.
As a bonus, this is all after they shit on the TTC procurement process due to Spadina cost-overruns which involved a death and a federal investigation. Seems Metrolinx didn't exactly dot their i's and cross their t's either. Eglinton will be over budget by the hundreds of millions too (double procurement of vehicles guarantees it, especially if Bombardier actually delivers).
A less risky alternative would have been tendering a Design+Build contract in 2015 when they did, and a separate Maintenance contract around 2020 after they see everything (both the build and the vehicle delivery) is on time. Or, a D+B+M but left open the option of determining the start date of the M portion.
Either the Metrolinx legal department messed up and didn't notice this as a massive red flag (agreeing to something you have no control over is generally frowned upon) or some executive (maybe even the board?) approved it despite that problem being raised as a risk.
