"The largest of the retaining walls is alongside the railway, [which is] some 330m-long and an average height of around 5m," the New Zealand Transport Agency project manager, Simon Underwood, said this week.
The installation of panels for a retaining wall in Bridge St was nearing completion, while the "South Rd wall" was expected to be completed by August. The railway wall is to be built up progressively, with construction work starting in July and continuing until September.
The "challenging weather" in February and March, that brought above average rainfall and affected some construction timelines, had been balanced by fine weather in May, allowing contractors to catch up on work schedules.
A duplicate Glen bridge overpass is about to be constructed, which would involve a piling rig in South Rd to establish two 13m-long pile casings in the ground using a vibration technique, Mr Underwood said.
Although this would involve less impact than hammer-driven piles, noticeable vibrations would be likely.
