Creating building pads along a polyline trajectory

Canal Trajectory.rvt (4.8 MB)
Need to create multiple bulding pads along a trajectory. It is simpler to create a single pad as in screenshot

However in that case, quantitative details at intervals cant be derived, only overall excavation volumes.
Please help if possible, I was hoping for some dynamo code to offset the polylines and generate pads at 50m intervals.