Cancel route oddity perhaps

Don't know what's specified for Doncaster, but in real life there were many boxes where the 120sec time-out applied as soon as the signal cleared, regardless of whether there was a train anywhere near. Comprehensive approach locking needed a lot more relays and circuitry; the extra £££ simply weren't in the budget when those boxes were built, except for a few locations within some boxes where it was expected routes might need to be pulled up and reset regularly and the time-out would cause problems.

thanks - can this be added to the manual please as its tripped me up !

Approach locking

Should you cancel a route ahead of a closely approaching train such that an approaching train incurs an ACOA, the interlocking will start a timer, known as approach locking, which gives the train time to stop. While that timer is running, the route will remain set to avoid any potential conflicts. The signal on the panel will flash red to indicate that the approach locking is in force (though the signal on the ground will show steady red). The timer duration depends on the location of the signal and the standards in force when the signalbox was designed. Typically, the timer will run for no less than 2 minutes for main signals (faster trains take longer to stop) and 30 seconds for shunt signals. For more details see Approach Locking .

Determining whether or not a train is approaching requires additional controls in the interlocking, in the form of additional wires and relays for older interlockings, or additional programming for modern interlocking. As this adds material, design and testing costs, some interlockings omit these controls, and assume that a train is always approaching. This means that approach locking will always be imposed. Additionally, approach locking is always imposed if the track approaching the signal isn't track-circuited, as there is no way of determining whether a train is approaching or not.

Note that triggering approach locking on its own does not lead to a penalty in the simulation score; only causing ACOAs does.

https://www.SimSig.co.uk/Wiki/Show?page=usertrack:ssrun:routing_trains