The summer holdays in January give an opportunity for major track works.
This summer it's Lygon St - from Elgin St in Carlton to Weston St in
Brunswick - around 2.5km.
See:
http://www.yarratrams.com.au/media-centre/news/articles/2017/tram-track-renewal-lygon-street-between-weston-street-and-elgin-street/
or https://tinyurl.com/y9syzfq6
Preliminary work has already begun, but the big push with 24 closure and
bustitution will happen over 2 weeks between January 3 and 17.
I attach the YT info sheet.
Mal Rowe - tempted to make comparisons with other construction timescales