That’s a “GT” on the milestone, as in 10 miles north of Grahamstown South Africa. Milestones were originally stone markers used by Roman road builders as a series of numbered markers provide reference points along the road. Milestones can be used to reassure travelers that the proper path is being followed, and to indicate either distance traveled or the remaining distance to a destination.
Funny story – on Nantucket Island, located off the coast of Cape Cod in Massachusetts, USA the road from town to Siasconset is named the Milestone Road. They have a Pi Milestone at 3.14 miles from town.
In a plant maintenance turnaround keeping track of the outage events and issues is a vital way for the organization to learn where they are and where they are going. Its almost impossible to reconstruct the battle after the fact; memories fade, rationalizations creep in. If you aren’t paying attention to the road markers and something happens how do you know where you are?
When all you measure is when the shutdown started and when it ended all you know is the total lost production time. When key steps along the way are planned and recorded you can learn where the time goes, and then take steps to attack the biggest deviations.