FRA emergency order 24 covers switches and protocols for operation in Dark territory. Signal suspensions are considered dark territory. If the present theory is true and a trainman left the switch open then this is three mistakes not just one. 1st mistake is the crew failed to restore mainline switch, 2nd mistake the crew may have violated FRA emergency order 24 and not signed off on the switch being opened and switch being restored. 3rd mistake the crew reported clear of the mainline and reported that the switch was restored to the dispatcher. FRA emergency order 24 requires both engineer and conductor to record the time and MP of when a switch is opened and when a switch is restored when operating in Dark territory. If this is normally CTC territory then the mental game of remembering that this is not a normal day and the DS will not restore the switch needs to be considered. I work for UP, when UP does a signal suspension all switches are spiked or clamped for the mainline or the movement that is directed by the foreman in charge of the suspension. Only one train at a time can be in the limits and dark territory speed rules apply. The track warrants will have specific instructions as to which signals are the 1st working signal on both sides of the limits. Trainman do not operate switches on the UP in the limits of a suspension only signal dept employees handle the switches. That being said a on run to Dunsmuir during a signal suspension I was diverted into Lakehead siding in error on a northbound train I went into the siding at 15mph over the speed limit I was lucky that there was nothing in the siding. Mistakes do happen and it may have had nothing to do with the crew.