Very common. Having read a lot of branch line histories I have frequently come across pictures of a group done up in their best togs with an engraved spade and often a decorated wheelbarrow. The wife or daughter of the chairman would delicately lift a small amount of earth, everyone would cheer and then they would all go for a massive blow-out.
It was probably slightly more common with branch lines as that was a source of local pride and local politicking. For an extension of a larger company or line it would probably be a bit more low-key, with one of the company’s senior staff and a couple of others using a new spade, but there was still a certain amount of publicity to be gained with having the ‘Deputy Chief Civil Engineer turning the first sod of the Buggleskelly Extension’. A large project, such as a drive to a new area, might still get the full treatment even with a major company.