A tunnel boring machine was built and certified for tunneling service in 2007 and then in 2014, it was decertified for tunneling service because it was no longer working and was disposed of.
The tunnel boring machine was certified and used for service for a total of 12 years.
How is that possible?
See Answer
It was built and certified for service in section 2007 and decertified and disposed of in section 2014 of the same factory.