ALRT technology can be retrofitted into the Sheppard Subway much more cheaply than low-floor LRT. ALRT cars are high-floor, like subway cars, but with smaller wheels, so ALRT can be fitted inside the existing tunnels without major modifications. Costs should be in the order of $20 million per km, or $50 million to convert the line. We allow $100 million, including construction of a portal (ramp) exit east of Don Mills Road.
This new line would be about half as long, and have fewer than half as many stations, as Vancouver's Evergreen Line. On this basis, it should be deliverable for about $700 million. We allow a further $200 million to refurbish the existing Scarborough RT for use by larger ALRT cars, including reconstruction of the Kennedy terminal to provide better interchange with GO Rail as well as with the subway and Eglinton line.
Extending the line 3.5 km from McCowan to Sheppard is equivalent in scale to about one-third of Vancouver's Evergreen Line, and so should cost about $500 million.
Development of the Scarborough Wye would displace about 20 subway cars currently operating on the Sheppard Subway Line. These may have a use elsewhere on the system; however we assume, pessimistically, that they are scrapped. We also assume replacement of the entire Scarborough RT fleet.
Total cost to integrate the existing Sheppard and Scarborough lines and extend them through to Sheppard east of Markham would be about $1.8 billion NPV, or $2.3 billion NPV including incremental operating costs, about 15% more than it will cost just to convert the Scarborough RT to LRT technology and almost certainly less than the cost to extend the Bloor Danforth subway.
Our estimates of costs are summarized in Table A12 in the Appendix.