What do the trains such as T, K and Guankuai stand for? thank you

D-EMU train Z-through express train T-express train K-inter-bureau express train N-inter-bureau express train L-inter-bureau temporary passenger train A-inter-bureau temporary passenger train Y-tourist train X-the number of baggage and parcel trains only consists of numbers: 1, and 2 starts with through passenger express train. Short for Express 1 * * *- Crossing three railway bureaus and above 2 * * *- Crossing two railway bureaus, the beginning of 4 and 5 belongs to the passenger express within the tube, and the short for Express belongs to the ordinary passenger slow train with the beginning of 6 and 7. Most of them are called express within the tube, and a few cross-bureau passengers are called through passengers. The specific sections are as follows: passenger transport: D: EMU D 1-D398 (inter-bureau train) D40 1-D998 (in-pipe train) D550 1-D5598 (EMU maintenance vehicle) Z: through train. -X 655 Universal Express:1001-kloc-0/998 (Universal Express across three or more offices) 200 1-3998 (Universal Express across two offices) 400 1-5998 (Pipeline Commuting: 760 1-8998 (commuting) l: inter-office passenger transport L 1-L998 (inter-office passenger transport) a: in-pipe passenger transport A 1-A998 (in-pipe passenger transport) y: tourist bus Y 1-Y498. Kloc-0/-44998 (off-hook) 4500 1-49998 (small operation) 5000 1-50998 (single operation) 51001-5/kloc-0. Kloc-0/-85998 (Shi Zhi) 8600 1-86998 (Zhi Zhi) 8700 1-87998 (Kong Zhi) 9000 1-9 1998 (Military).