Is it? That doesn't include any of the design/vehicle/property aquisition cost. That's the kind of costs where tunnels are $50-million per kilometre. An extra $20 million/km to elevate Eglinton East? That doesn't even pay for the extra cost of the elevated stations - let alone the track!
The vehicle cost for the ARL is $75 million. Factor that in to the 3km spur cost (which would inflate it even higher than what it should be), that's still only $67 million/km. That construction contract also includes the station at Pearson.
And besides, things like vehicles, design, and property acquisition costs would already be factored into the ~$60 million cost of the at-grade LRT. It's not like you're going to need any extra vehicles, or any additional property acquisition because you decide to build it above the centre of the road instead of in the centre of the road.
As for the additional costs of elevated stations, I found this from Wikipedia about the Canada Line: "A future station at Capstan Way (No. 3 Road and Capstan Way) in Richmond was originally planned, but was cancelled in March 2009. Pinnacle International and Concord Pacific, the developers of the Sun Tech City project couldn't fund the $15 million required to build the station."
By my count there would be 5 elevated stations on Eglinton East (Wynford, Bermondsey, Victoria Park, Warden, and Birchmount). Assume $20 million/station (a generous inflation based on what's above), and that's an extra $100 million. It's 5.75km from Kennedy to where it would go underground just east of Don Mills. That's $17.4 million/km in added cost to build the 5 elevated stations. Of course, then you need to factor in the money saved by not building 9 at-grade stops. Not sure exactly what an at-grade stop costs.
Given how much it's costing to build the elevated guideway into Pearson, it's reasonable to assume $20-30 million more per km than at-grade LRT is a pretty reasonable estimate.
