The EN range in UK was officially superseded 20 years ago, although a lot of older engineers still use the notation. En 16 was a common medium tensile steel used a lot for moderately highly stressed components. The 'T' is the heat treatment which put the UTS up to around 900 N/mm2, and was the most common treatment condition. It was sold in the T condition as it was still easy to machine in this condition.
BS970 (1983/1991) superseded the EN range and 605M36 is the nearest equivalent. For other internationally recognised equivalents, try UK steel manufacturers' websites.