Some special station codes:
.
(Railway gauges)
BG / Bhongir (SCR)
MG / Modelgram (NR)
NG...
more... / Nagari (SR)
.
(Class/Coach codes)
HA / Hargaon (NER)
AB / Ambur (SR)
G / Gondia (SECR)
J / Jalna (SCR)
S / Shrirangapatna (SWR)
D / Deula (ER)
UR / Umdanagar
SLR / Salogra (NR)
SRD / Surawadi(CR)
MST / Masit (NR)
HCP / Harchandpur (NR)
PC / Pachora Junction (CR)
.
Additions Welcome...!