This is the Hamm HD 12 VV articulated roller.
It is in the process of compressing the ground beneath what will become a cycle track.
It's 'an unexpectedly manoeuvrable piece of kit' as one of the workers correctly observed.
Skilfully driven, it could certainly climb steeper gradients than I would have predicted.
Although, at one point the excavator had to create a gentler incline so that the roller could regain the road level.