At "Technical" Halts, the trains have mandatory stop for technical reasons (like banker attachment / detachment, crew change, brake testing halt, etc). Such halts are seen in WTT (Working Time Table) and are not shown in Public TT. At "Commercial" Halts, the trains stops for travelers for boarding / de-boarding. The timings are shown in Public TT. And if the train arrives before time, it can not start onward journey before the departure time mentioned in Public / Zonal TT / TAAG!