How is that trains that are delayed unexpectedly at some point (sometimes) still reach their destinations on time or nearly so?
IR provides generous amounts of make-up time or slack (also known as Extra Time Allowed (marked ‘EA’ in the working timetable), or margin) in the schedules for most long-distance trains. Delays of half-an-hour to a couple of hours are almost inevitable in the running of most long-distance trains (except the ‘prestigious’ ones such as the Rajdhanis or Shatabdis, which are generally given great operational priority), and with good luck, the slack in the later portions of the journey will allow the train to make its destination on time. EA is specifically intended to account for delays caused by caution orders and track conditions, and any delays attributable to the train’s running itself (alarm chain pulling, late departure from a station, etc.) A further category of make-up time called Traffic Recovery Time (marked ‘TRT’) is also provided to allow for delays due to line and block section occupancy in heavy traffic. Finally there is Make-up Allowance, which is not a real make-up time but
