Safety First!

Clear and concise communications are critical on a real railroad. While no one will get killed by a model train as the result of a communications error, good communications will eliminate problems when trying to run multiple trains, just as it does on the prototype. Regardless, our goal is to simulate a real railroad; thus communication is a major role-playing activity.

While over the years most prototype railroads have tended to standardize on the same rule numbering and signal meanings, this has mainly been to facilitate ease in retraining employees coming from a competitors railroad. If you are a Freelancer, you could realistically create your own unique railroad communication schemes. Just be sure to document them in your Rulebook.

Rulebook

All businesses have a Rulebook, sometimes euphemized as an "employee manual". It is the top-level source where standing instructions/policies (such as "employees must wash their hands before returning to work") are either posted directly, or have their ancillary manuals specified. Railroads are businesses, and they especially require a Rulebook as the authoritative place to specify safety and operating information.

The model railroads Rulebook is the place where standing instructions for our simulated train crew (and we layout users) are kept. Every model railroad should have one, and at the very least it need only contain one sentence:
"Turn off the Main Power when you have finished using the layout.".

TimeTables

If you have ever ridden a bus or flown on a plane, you have been exposed to a slimmed-down Public Timetable. A Full Timetable is where information about all of the days planned train movements are listed. It displays snapshots of both When and Where a scheduled train is supposed to be. As such, a scheduled train must never leave ahead of its schedule. Timetables may be modified by an authorized authority, such as a Dispatcher [EXPLANATION], throughout the day (for example adding Extra trains to the timetable), as long as all affected parties are informed of the changes before they are scheduled to occur.

For a one-person layout timetables do not have to be physically printed. However the layout operator should keep the tables in his head, especially if he intends to have several trains in motion through a round-robin.

Selective compression of speed (*.pdf)
Timetable and Train-Order operation (*.pdf)
Creating a realistic model timetable (*.pdf)
Operate your layout using a prototype timetable (*.pdf)

Applied Scheduling Examples:
Model the city for a change of pace (*.pdf)
Division Point (*.pdf)
Steel Mill (*.pdf)

Orders/Warrants

An Order is a written superceding instruction from a superior (often in regards to the Timetable, but sometimes also the Rulebook).
A Warrant is a written permission slip from a superior (which is most often used for places lacking controlled trackside signals).

In the past Orders and Warrants had to be signed for from an agent, but nowadays some (especially Track Usage Warrants) can be transmitted directly via radio if the receiver confirms they have written them accurately.

Run trains with simple orders (*.pdf)
Running Extra trains (*.pdf)
Track Warrant Control (*.pdf)

Signals

Signals are nothing more than a way for railroad employees to indirectly communicate in real-time. You yourself for example receive signals on roadways in the form of traffic lights and road construction signs. Railroad signals can come in many forms, such as for example a blue flag indicating "Men at Work", a semaphore indicating orders are waiting for pickup, or a green light indicating clear to proceed. Signal types and meanings are railroad specific, and are thus described in that railroads Rulebook (in the same manner as each States unique roadway signals are described in the States DMV Rulebook).

The electronics in modern O-scale locomotives allows modelers to utilize signaling features that were not easily implemented in the past. You can ring the bell as a warning when backing, blow the whistle as an alert when crossing a road at grade, and most importantly, you can display meaningful timetable train marker lights [EXPLANATION].

Real railroads send their employees to class in order to learn the railroads unique signals. With our model we usually don't want to go to that extreme, so it is best that all signals used on the layout (and between operators) be kept SIMPLE and to a MINIMUM.

Maintenance Flags and Signs (*.pdf)
Railroad Traffic Signals (*.pdf)
Model Signal Spacing (*.pdf)
Walkaround Dispatching (*.pdf)

TIP: Even if you do not model a working trackside signal system, because prototype railroads will have them, you should at least place dummy trackside signal equipment on the layout as scenery.