As had been pointed out a few times on UT, successful conversions of premetros to full metros had been vanishingly few. Pretty much the only examples are Lines 1 and 2 of Brussels, Lines U2 and U4 of Vienna, and Line 2 of Rio de Janeiro. Vienna's lines basically required a complete rebuild (which took 5 years each) so are not the most comparable examples. The Rio line already started out with high-platforms, partial third rail and a separate ROW with grade crossings, and had a very low service frequency, but the conversion to full metro (mainly by removing grade crossings) still took 3 years. The stations of Brussels' premetro lines all have partial high platforms so that only part of the platforms need to raised for conversion; line 1 (2 km, 6 stations) took 4 years, line 2 (3.5 km, 8 stations) took a miraculous 2 years (compare that to Eglinton's 8-10 km, 12-14 stations), and none of the other lines had since been converted in 30 years. None of the German and American premetros, many of which have built-in conversion-ready features, have ever been converted in the past 100 years. As I've said before, given the trackrecord of TTC (and Canadian transit in general), I do not see we'll do any better, and Eglinton is unlikely to ever see conversion in the next 1-2 centuries.