ST-1, ST-2,up till ST-5 are from Tata and S-1 till S-8 are from Dhanbad. The issue generally seen is that the 'T' is completely missing in the coach numbering of Tata coaches and it appears as S-1, S-2. There is total confusion in intermediate stations when passengers end up seeing two coaches with the same numbering.Had witnessed this at Aluva, TCR stations two weeks ago with the huge puja rush. Train was on its way to Dhanbad and there was total confusion/chaos at these stations .Passengers have to run from one end to another if they board the wrong coach or seek TTE help .It could have been better if numbered as S-9 S-10 up till S-13.