Something may have changed more recently. The first stage of the Eglinton Crosstown LRT line in Toronto looks like it will come in at around (converting currency and distances) 9B for 12 miles. Locals generally don't seem to think this represents a success. (Despite being light rail, about 2/3 of this first stage will run underground.)

(The REM in Montreal - https://www.cdpqinfra.com/en/projects/rem - is doing much better than that, despite going over budget and being delayed quite a bit.)