AlvinofDiaspar
Moderator
Look at the whole Scarborough RT fiasco right now. We are talking about replacing the deteriorating SRT with a costly subway, which is politically difficult.
Wasting a billion to build the Sheppard LRT then replacing it with a subway 20 years later when it becomes overcrowded (which would require closing the LRT during construction because of the plan to put the Don Mills end of the LRT underground) is a lot more expensive than simply building the Sheppard subway extension to begin with. The difference with replacing the old streetcar system with the Yonge and Bloor subways is that the old streetcar lines were built in the 19th century when Toronto was not a very big city and then was replaced with a subway almost 100 years later.
Except that a) there is no evidence your line will be overcrowded in 20 years for one, b) the whole SRT fiasco has to do with the use of non-standard technologies with no economies of scale with the rest of the system, and not the lack of capacity per se.
The issue isn't the age of the old streetcar lines - it is, and should always be whether ridership justifies replacing it.
AoD