Just got a conformation from one of my known contacts who travelled in Kalka Mail and arrived Yesterday that it was actually a 25 coacher.
This was the CC for Kalka mail which arrived yesterday morning.
SLR-D1-GS-S1-S2-S3-S4-S5-PC-B1-A1-B2-B3-A2-A3-HA1-S6-S7-S8-S9-S10-S11-GS-GS/RMS-SLR-LOCO.