A partial subway closure on TTC Line 2 could last 'a few days' after a fire

 https://toronto.ctvnews.ca/partial-subway-closure-on-line-2-could-last-a-few-days-after-fire-ttc-says-1.6862790

There can always be better redundancy by having enough parallel bus routes.

https://www.cp24.com/news/partial-subway-closure-on-line-2-could-last-a-few-days-after-fire-ttc-says-1.6862785

So whenever a train line is out of service, the number of buses can be quickly increased.

https://www.cbc.ca/news/canada/toronto/ttc-subway-kipling-jane-closure-1.7185757

https://www.ttc.ca/service-advisories/subway-service#e=0