AB= Combo of AC 2 tier and 3 tier ,will be like AB1, AB2...
F=First Class, will be like F1,F2...
E=Executive AC Chair Car, E1,E2..
CC=AC chair car, C1, C2, C3...
D=Reserved non-ac second sitting,...
more... like D1, D2, D3...
G=AC 3 tier of Garib Rath, like G1, G2, G3...