But that's not quite right, since it contradicts the previous announcement that the groundbreaking for 535 Carlton would be on Monday, December 15. Indeed, a Forest City spokesman confirmed in response to my query that it's still scheduled for that day.
Update: a revised alert was sent out, noting:
The ground breaking ceremony for 535 Carlton will take place on December 15th and the construction of 535 Carlton and 550 Vanderbilt will commence on December 16th.Over the next two weeks, "[s]ubject to construction activities, the contractor will begin mobilization of trailers" to that site, aka B14.
Other parts of the Construction Update indicate that steel deliveries for the arena green roof will continue to the B3 and Atlantic Avenue crane locations.
Regarding the Vanderbilt Yard, drilling of support of excavation (SOE) piles on the eastern side of Sixth Avenue will continue and it "is not currently anticipated that this work will take place at night."
LIRR trailers currently located near the Vanderbilt Avenue end of the block will be removed during this reporting period.