The closest I can get to clarity on the BRT number comes from Metrolinx's 2010 report Hamilton King-Main Rapid Transit Benefits Case
, where the short list of options is broken down in 2008 dollars.
Option 1 (Full BRT) = $218m capital costs [~$238m 2012]
Option 2 (Full LRT) = $829m capital costs [~$905m 2012]
Option 3 (Phased LRT) = $605m capital costs [~$660m 2012]
Phased LRT would run from McMaster to Ottawa Street, "deferring some of the costs and benefits attributable to the full LRT to provide an opportunity for the eastern section of the corridor to mature to a point where such an extension could generate greater benefits and re-development up-lift from the LRT investment." Metrolinx assumed a 15-year lag for that to take place.