| alinement | The horizontal location of a railway with reference to curves and tangents. |
| branch line | The secondary line or lines of a railway. |
| curve, simple | A curved track forming an arc of a circle of a single radius. |
| curve, degree | The angle subtended at the center of a simple curve by a 100-foot chord. |
| curve, compound | A continuous change in direction of alinement by means of two or more contiguous simple curves of different degrees having a common direction at their junction points. |
| curve, easement | A curve whose degree varies either uniformly or in some definitely determined manner so as to give a gradual transition between a tangent and a simple curve, which it connects, or between two simple curves. |
| curve, reverse | Two contiguous simple curves in opposite directions, with a common direction at their junction point. |
| curve, vertical | A vertical bend in the track to connect intersecting grade lines. |
| connecting track | Two turnouts with the track between the frogs arranged to form a continuous passage between one track and another intersecting or oblique track or another remote parallel track. |
| crossover | Two turnouts with the track between the frogs arranged to form a continuous passage between two nearby and generally parallel tracks. |
| crossover, double | A combination of two crossovers in opposite directions, which intersect between the parallel tracks. |
| crossing (track) | A device used where two tracks intersect at grade to permit the traffic on either track to run across the other and comprising four connected frogs, one for each rail intersection. See frog. (For details, see " Crossing Terms.") |
| elevation (of curves) | The vertical distance that the outer rail is raised above the inner rail, sometimes called Superelevation. |
| fastenings | Splice Bars, Bolts and Spikes. |
| fastenings, auxiliary | Nutlocks, tieplates, rail braces and anti-creeping devices. |
| flangeway | The space between the running rail and a guard rail which provides clearance for the passage of wheel flanges. |
| flangeway depth | The vertical distance from the top of the running surface of the running rail to the top of a filler or separator introduced between the running rail and guard rail. A minimum depth has been standardized at 1 7/8 inches. |
| flangeway width | The distance between the gage line of the running track rail and the guard line of the adjacent guard rail. The standard flangeway width on straight track is 1 3/4 inches. |
| flare | A tapered widening of the flangeway formed by beveling or bending the end of a guard rail or frog wing away from the gage line. |
| flare opening | The horizontal distance between the gage line of the running rail and the side of the head of the guard rail or frog wing rail at the point of maximum opening. |
| foot guard | A filler, preferably of metal, designed to fill spaces between converging rails to prevent the feet of persons becoming accidentally wedged between the rails. |
| frog | A device used where two running rails intersect and providing flangeways to permit wheels and wheel flanges on either rail to cross the other. (For details, see "Frog Terms.") |
| frog guard rails | A rail or other device to guide the wheel flange so that it is kept clear of the point of the frog. |
| gage (a Tool) | A tool by which the gage of track is determined. |
| gage (of Track) | The distance between the heads of the rails measured at right angles thereto at a point 5/8 inch below the top of the rail. |
| gage, Standard | The gage of 4 feet 8 1/2 inches. |
| gage line | A line 5/8 inch below the running surface of a rail on the side of the head nearest the center of track. |
| guard rail | A rail laid parallel to the running rails of a track to prevent wheels from being derailed, or to hold the wheels in proper alinement to the track to prevent their flanges from striking the points of switches, or the points of frogs in turnouts or crossings. (For details, see "Guard Rail Terms.") |
| insulation | A device or material that prevents the flow of electric current in a track circuit from passing from one rail to the other or through switches and other track structures. |
| joint bar | A metal angle bar or other shape used in a rail joint and fitting into the sides between head and base of the abutting rails. |
| joint (rail) | A fastening designed to unite the abutting ends of contiguous rails. |
| joint, insulated | A rail joint designed to arrest the flow of the electric current from rail to rail by means of insulations so placed as to separate the rail ends and other metal parts connecting them. |
| level | The condition of the track in which the elevation of the rails transversely is equal. |
| line | The condition of the track in regard to uniformity in direction over short distances on tangents, or uniformity in variation in direction over short distances on curves. |
| lining track | Shifting the track laterally to conform to the established alinement. |
| main line | The principal line or lines of a railway. |
| main track | The running track of a railway whereon the movement of trains is controlled by timetable, train order or block signal. For multiple main track generally the southerly or easterly main track shall be designated as the first main track and the adjacent one as the second main track, etc. |
| out of face (referring to track work) |
Work that proceeds completely and continuously over a given piece of track as distinguished from work a disconnected points only. |
| scissors crossover | See crossover, double |
| slip switch, single | A combination of a crossing with one right-hand and one left-hand switch and curve between them within the limits of the crossing and connecting the two intersecting tracks without the use of separate turnout frogs. |
| slip switch, double | A combination of a crossing with two right-hand and two left-hand switches and curves between them within the limits of the crossing and connecting the two intersecting tracks on both sides of the crossing and without the use of separate turnout frogs. |
| spiral (when used with respect to track) |
A from of easement curve in which the change of degree of curve is uniform throughout its length. |
| spiral, ten chord | An approximate spiral measured in ten equal chords and whose change of degree of curve is directly proportional to the length measured along the spiral by such chords. |
| splice drilling | The spacing of holes in the ends of rails or other track structures to receive the bolts for the fastening of joint bars. |
| split switch | A device consisting essentially of two tapered movable rails with necessary connections, designed to divert rolling stock from one track to another. (For details, see "Switch Terms.") |
| spur | A line of railway diverging from a main or branch line, and over which no regular train service is maintained. |
| surface (when used with respect to track) |
The condition of the track as to vertical evenness or smoothness over short distances. |
| surface, running (tread) | The top part of track structures on which the treads of the wheels bear. |
| switch | A device consisting of two movable rails, necessary connections and operating parts, designed to turn an engine or train from a track on which it is running to another track. |
| tangent | Any straight portion of a railway alinement. |
| track | Ties, Rails, and Fastenings; with all parts in their proper relative positions. |
| track bolt | A bolt with a button head and oval neck and a threaded nut designed to fasten together rails and splice bars and other rail joint fastenings. |
| turnout | A track arrangement consisting of a switch and frog with connecting and operating parts, and extending from the point of the switch to the heel of the frog, by means of which engines and cars may pass from one track to another. (For details, see "Turnout Terms," "Switch Terms" and "Frog Terms.") |
| wye | A principal track and two connecting tracks arranged like the letter "Y," with the top closed, by means of which engines and trains may be turned. |
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