abutment — The concrete or timber curb upon which a railroad bridge deck rests All bridges have two abutments, one on either side, though the two may not be of the same material.
automated block signal (ABS) — A system that uses a combination of electric signal flags, traffic lights, and other signage to control railroad activity along a corridor. Used between Vasona Junction and the Santa Cruz Depot from 1909 to 1940.
ballast — Loose rocks set beneath railroad ties to even the grade and provide shock absorption.
bed — Also called the rail bed. The surface upon which railroad tracks are placed. Usually composed of cross-ties, ballast, and earth.
bridge — A manufactured span that allows a right-of-way to cross a gap. Can be constructed out of wood, metal, or a combination of the two.
causeway — A type of bridge that runs a long distance over a relatively level surface in order to maintain an even grade.
cross-beam — A plank that connects two or more piers of a trestle bridge to improve support and stability.
cross-tie — Also simply tie. In Santa Cruz and Santa Clara Counties, usually heavily treated redwood logs, shaped into rectangular blocks, evenly spaced along a grade so as to support lengths of railroad track. Cross-tie dimensions differ greatly, but narrow-gauged ties are generally between six and seven feet in length, while broad-gauged ties are generally seven to nine feet in length.
cut — A section of earth removed to allow for a right-of-way.
daylight — The act of removing the ceiling from a tunnel, thereby exposing it to the sun.
deck — The section of a bridge that supports the railroad ties and tracks.
depot — A railroad station with seasonal or full-time staff.
double-head — A train running with two locomotives at its head. Usually required when steep grades are anticipated along a route, such as in the Santa Cruz Mountains.
dual-gauge — A track that has rails for two different gauges of rolling stock. Dual-gauged tracks in the Santa Cruz Mountains were standard-gauged, on the outside, with a third rail between them to support narrow-gauged rolling stock.
engine house — A structure used to store engines when not in use; often also include limited facilities to repair and maintain locomotives and rolling stock.
fill — An artificial earthen mound used to maintain a constant grade along a right-of-way. Often also refers to the material used to create a fill.
flag-stop — A type of station with no mandatory stops, but where a rider can board a train when a flag (or other device) is raised. A stop can be both a full stop and a flag-stop on different train schedules.
grade (ascent) — An uphill or downhill portion of a right-of-way, generally recorded as a percentage.
grade (right-of-way) — An artificial leveled road topped with ballast upon which railroad ties can be placed to create a right-of-way.
half-trestle — A type of trestle bridge that is supported on one side by a hill and on the other by pilings and cross-beams.
junction — A place where a railroad track splits into two or more branches, spurs, or sidings. May also describe the physical split in the track.
narrow-gauged — Any gauge of railroad track that measures less than the U.S. standard-gauge. The South Pacific Coast Railroad and its subsidiaries used a gauge of 3 feet (0.91 meters) between rails. Narrow-gauge is used most frequently on private and low-budget railroad lines, or those that require steep ascents.
piling — A cylindrical wood trunk, generally made of redwood within Santa Cruz and Santa Clara Counties, that is anchored deep in the ground to provide support for trestle bridges, wharves, and other railroad features.
pier — A concrete, metal, or wood foundation block placed beneath joints or areas of stress under railroad bridges.
planing mill — A large-scale timber processing facility that focuses on manufacturing various sizes of lumber.
plate girder — A metal support structure that underlies the deck in a railroad bridge.
portal — The entrance to a railroad tunnel.
quicklime — A term used to describe a powdery white alkaline product chemically known as calcium oxide (CaO). Unstable in the open air unless mixed with water. At the turn of the century, it was used heavily in cement mixes, plasters, and bricks.
right-of-way (r.o.w.) — The area within which railroad tracks exist, including a number of feet adjacent to the tracks on either side.
rolling stock — The locomotives, passenger cars, freight cars, and service vehicles owned by an individual or company.
semaphore — A pole which holds up a signaling device in an automated block system (ABS).
shingle mill — A small-scale timber-processing facility that focuses on manufacturing house shingles, railroad cross-ties, pickets for fences, grape stakes, firewood, and low-quality wood products.
siding — A parallel length of track that joins to the primary track on both ends.
sink — A natural occurrence where a right-of-way collapses due to an unstable surface.
slide — Also landslide. A natural occurrence where a hillside collapses onto the right-of-way.
spur — A length of track that branches off from the primary track and later terminates. Often short and used for loading freight or servicing passengers, though some spurs can be miles long.
standard-gauged — The gauge of railroad track most widely recognized and used in the United States. Measurement between rails is 4 feet, 8.5 inches (1.435 meters).
station — Any published place where a train can have a scheduled or flagged stop.
stop — Any place where a train can stop, including locations not formally published such as privately-owned freight sites.
switch — A device used to move a track between spurs or branches. See also junction.
switchback — A series of two or more short segments of track zig-zagging down a hillside. Installed in order to allow trains to descend a grade relatively quickly without requiring extensive bridging or prohibitively steep grades. Most common along private spurs.
timetable — A schedule noting when certain trains arrive at specific stations. Additional information in employee timetables often includes distances between stations, a list of flag-stops, siding and spur lengths, and services provided at each stop.
trestle — A type of railroad bridge design constructed using pilings and cross-beams in even rows. In the Santa Cruz Mountains, all trestle bridges were made of redwood, though concrete and metal trestle bridges exist elsewhere.
truss — A type of railroad bridge component which consists of rafters, posts, and struts designed in a consistent, repetitive pattern. Usually built from preexisting designs and named after its designer or appearance. Types of truss bridges used around the Monterey Bay and in the Santa Cruz Mountains include Howe, Warren, Pratt, and lattice.
turntable — A device used to turn rolling stock around. Often found at a terminus or at the highest point of a grade.

wash — Also washout. A section of right-of-way that has been removed through natural causes, generally undercut by water.