Railroad operations?

Question

track warrant controls, signals.

Answer 1

TWC (Track Warrant Control), CTC (Centralized Traffic Control), and DTC (Direct Traffic Control) are all control system on American Railroads.  TWC is also called Dark Territory meaning no signals.  All the others have a signal system in place to help direct rail traffic.

Answer 2

A track warrant is a piece of paper, usually copied by instructions from the dispatcher over the radio or by telephone, giving a train crew or maintenance employees authority to occupy a particular section of track. They are most commonly used on rail lines that do not have signals, but some railroads also apparently issue them to trains operating through signalled territory as a procedural matter of some sort. Why in the world would you want to know.

Answer 3

No track can be occupied by a railcar or train or workman without some sort of authority.

Track warrants are one form of authorization, and they are also a means of communicating conditions that affect the use of a peice of track, for instance speed restrictions due to work or track conditions. They can be used with or without track signals depending on the type of territroy and rules they operate under.

Signals can be almost anything, speed boards, whistle signs, station signs, and hand signs are all forms of signals.

The signals that most people think of are the lights that are similar to traffic lights, there are many rules governing signals and their use.

The signal indication alone can be a form of track authority depending on the type or territory or they can merely be a means of determining if a peice of track is already occupied.

There is very little in railroading that can be covered by a simple answer.

Hope this helps, it is a rather broad spectrum question and not easy to answer with a short and to the point answer.