According to the Auditor General of Ontario:
https://www.auditor.on.ca/en/content/annualreports/arreports/en20/20VFM_06metrolinxgov.pdf Pages 5-6
"The Ministry was aware as early as 2016 that the total cost estimate for the Hamilton LRT would be higher than the $1 billion in capital costs that the province had publicly committed to funding in 2015, but it did not make this fact public. The $1 billion was sufficient to cover only the project’s initially estimated construction cost. Subsequently, in December 2016, Treasury Board approved a budget of $2.981 billion for the project, based on estimated costs that 6 included $823 million in construction costs. In March 2018, Treasury Board approved a revised cost estimate of $3.659 billion, including construction costs of $1.083 billion, because the LRT’s estimated length had increased. We found that the 2016 and 2018 estimates did not represent the full cost of the LRT and were significantly understated. These estimates were not made public at those times.
Based on a detailed review, we found that the $5.5-billion cost estimate reported by the Minister of Transportation in December 2019, when the project was cancelled, was reasonable."
So no, this wasn't a case of the PCs spinning stuff.