Why do Beijing buses start with the word "special"?

Buses like Te 1 and Te 2 are double-decker buses, or some new things are very special in Beijing, so the bus company gives these lines a special title "Te".

A few years ago, because Chang 'an Avenue refused to take the double-decker bus, the dedicated 1 bus was cancelled, and the dedicated 2- 9 bus was reserved. Later, the dedicated 10 bus was opened.

During the Olympic Games, Beijing Public Transport Group opened a number of sightseeing routes, all of which were double-decker buses. After the Olympic Games, these vehicles were added to the regular routes, such as No.23, No.72, No.406, No.803 and so on. , is now driving on the road. Now prefix line is no longer synonymous with double-decker bus.