Final answer:
The rule number for Blue Signal Protection of Workmen (Other Than Main Track 2) in engineering is Rule 110. This rule provides guidelines for protecting workmen on the railway tracks. Blue Signal Protection is important for ensuring workmen's safety.
Step-by-step explanation:
The rule number for Blue Signal Protection of Workmen (Other Than Main Track 2) in the field of engineering is Rule 110. This rule is part of the Operating Rules of the American Railway Association (ARA) and provides guidelines for protecting workmen on the railway tracks.
Under Rule 110, when workmen are working on or near railway tracks, a blue signal should be displayed to indicate the presence of workmen. This signal is typically a blue flag, blue light, or blue tag.
The purpose of Blue Signal Protection is to ensure the safety of workmen by warning train crews and other track workers that work is being performed in the area. It helps prevent accidents and allows workmen to perform their duties without the risk of being struck by a moving train.