Track Warrant Control on the Pacific & Eastern


Track Warrant Control (TWC) is a verbal authorization system defined by the General Code of Operation Rules (GCOR), used to authorize trains to occupy Main Tracks outside of Yard Limits. TWC can be used as a stand-alone dispatching and safety system in unsignaled territories, or can be supplemented with Automatic Block Signaling (ABS) to increase flexibility and traffic capacity.

The Track Warrant permits a specific train to occupy a specific piece of Main Track between named locations. The Track Warrant also contains information of its own validity; when comes in effect and in some cases when it becomes void.

The Track Warrant

A Track Warrant is issued in the following steps, usually using radio:

  • The dispatcher reads the Track Warrant information and instructions to a crew member on the train. The crew member writes the information and instructions on a Track Warrant Form (see below ).
  • The train crew member then repeats the information to the dispatcher.
  • The dispatcher checks the information and, if correct, says "OK" and gives the time and his initials.
  • The train crew member then enters the "OK" time and initials on the Track Warrant form and repeats them to the dispatcher.

The Track Warrant is not in effect until the "OK" time is shown on it. If the Track Warrant restricts train movement or previously granted movement authority, the dispatcher can not consider the Track Warrant to be in effect until his "OK" has been acknowledged by the train crew member.

The Track Warrant Form

The Track Warrant form varies somewhat from railroad to railroad. Below is shown the form used on the Pacific & Eastern. 

The upper 2 lines identify the Track Warrant by a number, a date, the train in question and the location of the train when the Track Warrant is issued.

After this follow 10 standard instruction fields plus one field for non-standardized instructions. Only some of the instruction fields are used in a given Track Warrant. The instruction field is numbered, and each field has a box to the right of the number. A check-mark in this box marks the instruction field as being in use of this Track Warrant. A typical instruction would then be: "Check Box 1, Track Warrant NO. 234 Is Void."

The instruction fields are described in detail in the following sections.

The 3rd line from the bottom holds information on the "OK" time and dispatcher initials. The 2nd last line states that the Track Warrant has been received and the name of the crew member who copied it. The last line it used to note when Limits are reported clear to the dispatcher.

Track Warrant Limits (Boxes 2, 3, 4, 7, and 8)

Boxes 2, 3 and 4 defines the limits of the Track Warrant. Boxes 7 and 8 helps define the exact end of the Limits on a Station with a Siding.

Boxes 2 and 3 are identical. They simply define that the train may proceed from location A to location B, and in case of multiple Main Tracks, on which track. The need for 2 boxes is to allow for the train to move from Main Track to another Main Track. It's important to keep in mind that the Track Warrant must include all Main Track allocated to the train, also the Main Track occupied by the rear end of the train.

While boxes 2 and 3 gives permission to move in the direction specified only, box 4 allows the train to move in both directions on that section of track. This may be handy when a train is doing local switching in an area.

The start point in the Track Warrant is normally referred to as the First Named Point, while the end of the Limits are referred to as the Last Named Point. The named points may be any point that can be exactly identified, such as switches, mile posts or Stations.

Pacific & Eastern                 Track Warrant

NO: ____________                _________20_____

To:  _______________  At: _________________

1 *  Track Warrant NO. ________is VOID.

2 *  Proceed from___________________to____________________

3 *  Proceed from___________________to____________________

4 *  Work Between__________________and___________________

5  *  Not in effect until arrival of ____________at_________________

6  *  This authority expires at ________________________________

7  *  Hold Main Track at last named point

8  *  Clear Main Track at last named point

9  *  Between _________________and _________________make all

            movements at restricted speed.  Limits occupied by train,

             engines, men or machines. 

10 * Do not exceed ____MPH between __________and___________

11 *  Other specific instructions: ______________________________


                OK __________ M     Dispatcher ___________

                                                            Copied _____________

          Reported Clear at _______M  By _____________



Track Warrant in Effect when (Boxes 1, 5 and 6)

An important part of a Track Warrant is to define when it is in effect. Unless boxes 1, 5 or 6 indicates differently, Track Warrant is in effect as soon as the dispatcher has checked its correct reception by the train, and remains in effect until the train has reported the Limits clear.

Track Warrant is void (Box 1)

Box 1 is used to replace one Track Warrant with another. The typical use is when a train gets its Limits extended due to a train ahead proceeding further away, into a siding or on to another line. The new Track Warrant will include the "unused" Limits of the old Track Warrant.  When a Track Warrant has been voided by the issuance of a new Track Warrant or by a train clears the limits of a Track Warrant by entering a siding or Yard Limits, the word “VOID” will be written in large letters across the voided Track Warrant.

Meets (Box 5)

When trains meet in single track territory, it is important for the met train to be able to depart as soon as possible. Box 7 facilitates issuing a Track Warrant to a train waiting for a meet by stating that the Track Warrant is "Not In Effect Until After Arrival Of <train> At <location>". Location should be identical to First Named Point.

Time Limits (Box 6)

A Track Warrant may be limited in time. A typical use for this would be a window for a work train or a local switch job necessitating to foul the Main Track. Box 6 defines the expiry time of the Track Warrant. The train must have cleared the Main Track before this expiry time. However, the Track Warrant remains in effect until the Limits are reported clear by the train.

Restricted Speed (Box 9)

Though a Track Warrant usually assigns a section of Main Track to one train only, it is sometimes necessary to be a little more flexible. Box 9 instructs the train to move at Restricted Speed between named locations, typically mileposts.


Box 9 is used when another train is on that particular section of track. The perhaps most typical use of box 9 is when more than one trains are working in the same are. The trains must move at restricted and thus keep a lookout for each other.

Speed Reductions (Box 10)

Box 10 instructs the train of speed reductions on the line. The speed reduction is in effect between 2 named locations, typically mileposts.

Other Instructions (Box 11)

Box 11 facilitates passing other safety related information to the train. In unsignaled territory such information could for example be that may be that a previous train has left a Main Track switch open after a meet.



Adapted form Carsten Lundsten (