Just to temper expectations, as far as I know, no active construction is occurring on the Kitchener Line west of Bramalea right now.
The RfP for construction of Work Package 2A of the Guelph Subdivision upgrades is scheduled for release this month:
"Kitchener Extension | Guelph Subdivision
Package 2A: Track and signals work, grading, drainage, and utility relocations in the Town of Halton Hills (Acton) in support of Kitchener GO service extension."
The RfP for construction of Work Package 4 of the Guelph Subdivision upgrades is scheduled for release 4Q2024 (Oct - Dec 2024):
"Kitchener Line Extension | Guelph Subdivision
Package 4: Track and signals work, platform work, grading, drainage, and utility relocations in support of Kitchener GO service extension." Thought to be the tie in of track to the new platform at Guelph Central Station.
I think this corresponds to the new infrastructure needed to support hourly counter peak / off-peak service described by reaperexpress above. Allowing time to award the work and for construction, perhaps we will see hourly service to Kitchener in 2026.
There are other work packages listed for the Kitchener line, including: an island platform at Georgetown Station, removal of the north platform at Mt Pleasant to make room for a 4th track, and construction of a new layover yard between Winston Churchill Boulevard & Heritage Road. It was also noted in a Metrolinx Board Mtg that CN has requested proposals for the design of upgrades to the Halton Subdivision (Georgetown to Bramalea), which may include the grade separated junction located between the Credit River bridge and Winston Churchill Boulevard and additional tracks (3rd track at Brampton Station, 4th track elsewhere). These would support even better service but will take 4 years at least to deliver at the current investment level.