5.4.3 Display of Yellow-Red Flag
B. Restriction Is Not Specified in Writing
When a yellow-red flag is displayed and the restriction is not specified by
a track bulletin, track warrant, or general order, crew members must be
prepared to stop short of a red flag 2 miles beyond the yellow-red flag. If
a red flag is displayed, proceed as outlined in Rule 5.4.7 (Display of Red
Flag or Red Light). If no red flag is displayed:
1.. Move at restricted speed.
2.. Increase speed only after:
a. A crew member has received permission from the employee in charge.
b. The rear of the train has passed a green flag.
or
c. The rear of the train has travelled 4 miles beyond the yellow-red flag,
and the train dispatcher has verified that no track bulletin or track
warrant protecting men or equipment is in effect at that location.
a.. So from the above, one would assume you'd contact the dispatcher for
further instructions.