encyclopedia

TRACE TREE

In planning, the sequence of modes that defines the links that make up the shortest path between two zones. (TRB)

TRACK ALLOCATION NOTICE

Published weekly summary that indicates specific contractors, maintenance and test personnel that will be be scheduled to work on the Red Line system for the following week. It indicates that limits, time, and dates of the week for these activities.

TRACK CAR

A self-propelled rail car (e.g., burro crane, highway rail car, detector car, weed burner, tie tamper) that is used in maintenance service and that may or may not operate signals or shunt track circuits. (TRB)

TRACK CHART

A document which graphically depicts the alignment, grade, track layout, track structure (weight of rail, age of ties, etc.), and other information (bridge locations, towns, crossings, etc.) about a railroad line. It is usually scaled at one-half to two inches…

TRACK CIRCUIT

An electrical circuit of which the rails of tracks form a part.

TRACK CONNECTOR (NRC)

Designated track auxiliary to Mainline track used to transfer rail vehicles.

TRACK CROSSING

A track structure used for one line of track to cross another, consisting of two frogs and connecting rails. An element of special trackwork. Often referred to as a diamond.

TRACK CROSSING (RAILWAY CROSSING)

An assembly of rails and frogs that allows crossing of two tracks at grade. (TRB)

TRACK INSTRUMENT

A device in which the vertical movement of the rail or the blow of a passing wheel operates a contact to open or close an electric switch. (TRB)