I'd like anyone's insight into the difference between general orders, circulars, instructions, and notices. The GCOR says:

1.3.2 General Orders

General orders:
Are numbered consecutively.
Are issued and canceled by the designated manager.
Contain only information and instructions related to rules or operating practices.
Replace any rule, special instruction, or regulation that conflicts with the general order.
Before beginning each day's work or trip, trainmen, enginemen, and any others whose duties require, must review general orders that apply to the territory they will work on.

1.3.3 Circulars, Instructions, and Notices

Circulars, instructions, notices, and other information are issued and canceled by the designated manager. Before beginning each day's work or trip, trainmen, enginemen, and any others whose duties require, must review those that apply to the territory they will work on.

We got into a substantial discussion today on the tourist line I work for as to what is the appropriate form to issue information in. If a car is taken out of service for a day or two, is that a notice, a circular or an instruction? If there is a temporary obstacle along the ROW that means bad footing for anyone getting off a train, is that an instruction or a notice?

Would appreciate any help in sorting this out.