cause 6458 to be delayed further while 6460 crosses in front of it to reach the siding.
So, if he lets 6460 into the siding first, will it be quick enough to allow 6458 a clear run in? He will chance it because he knows from experience that the driver will want to get the train stabled quickly because it is the end of his duty.
Fig 7 - A second route is selected
The signalman has decided to move Train 6460 into the siding across the path of 6458 and he has set up the route as shown in Fig 7. The white track circuit displays show that the route is set up and locked. The white diagonal on the icon of shunt signal C25 shows that the signal is showing proceed to the driver of Train 6460.
The Third Train Arrives
Time has moved forward a few minutes (Fig 12) and the signalman (to his annoyance) has seen no movement from Train 6460. However, by this time, Train 6458 has arrived on Track Circuit 102 and is standing at Signal C20. Already late, he will now be even later waiting for 6460 to clear the route.