In project management, you can never underestimate the value of good estimation, especially when it comes to managing expectations with respect to timing and the completion of projects. Take for example the process of electrifying a railway line.
The East Coast Main Line (ECML) is an electrified, high-speed railway line that runs between London in the United Kingdom and Edinburgh in Scotland. The line is 632 kilometres long and runs through several districts.
The ECML was not always electrified, however, and in 1985 the UK government sponsored a massive electrification project. This project impacted on signal systems along all 632 kilometres of railway track. The project managers working on this project had never had to test that many signals, going through so many different districts.