Some breakdown crane terminology explained

Articulated Jib Jib with the pivot holes at the foot slotted to allow the stowed jib to follow the line of the jib runner when the crane is run in a train
Auxiliary Hoist Smaller capacity hoist for faster and easier management of light loads
Ballast As “Counterweight”
Banksman Person on the ground responsible for directing the operation of the crane
Beam Occasionally used in place of "Prop", "Girder", or "Outrigger"
Blocking Action of deploying a crane’s props/outriggers to increase stability
Bolster Crossmember or stretcher (See also “Jib Rest”)
Boom An extensible (telescopic) jib
Bottom Block Sheave block from which the main hook is suspended
Bridle Gear Bars and links forming part of the derricking tackle, often carrying sheaves
Burden The load being hoisted, hence Burden Ropes (the ropes supporting the bottom block) and Burden Drum (the drum around which the ropes are wound for hoisting)
Capacity The maximum load that the crane is designed to lift
Carriage The rail-mounted truck on which the superstructure sits
CEPS The Civil Engineers Plant Scheme numbering applied to on-track plant from 1974-on
Centre Pin Pin or hollow shaft about which superstructure revolves
Counterweight Balance weight, normally on the superstructure. Can be fixed, movable or removable ( See also "Kentledge")
Crab A colloquial term for the superstructure
Derricking The act of raising or lowering the jib, hence Derricking Ropes (the ropes used for derricking) and Derricking Drum (the drum around which the derricking ropes are wound).  Also known as "Luffing"
Diesel Hydraulic Powered by a compression ignition engine driving one or more hydraulic pumps, with hydraulic motors or rams providing the motions
Diesel Mechanical Powered by a compression-ignition engine driving through either a conventional clutch and gearbox or a torque converter, and thence by mechanical means to the motions
Double Lattice Jib Jib of open ''X' or other diagonal lattice construction. More commonly referred to as, simply, a Lattice Jib
Exhaust Box Trap for removal of condensate from exhaust steam flow
Falls The number of lengths of rope in a run.  Typically refers to the number of drops to the bottom block
Fast Gear Gear for hoisting light loads faster and with more economical use of steam
Girder An alternative name for a “Prop”
Hoisting The act of lifting a load suspended from the hook
Hook Block As “Bottom Block”
Horse As “Jib Rest”
Jib Adjustable arm projecting from the crane, the outward end of which carries one or more load pulleys
Jib Rest Bolster on a jib runner for supporting the nose of the stabled jib
Jib Runner A wagon upon which the jib rests when the crane is running in train formation.  (See also "Match Wagon")
Kentledge Ballast that can be removed and carried on a wagon, to lighten crane axle loads for travelling
King Pin As “Centre Pin”, though more often applied to early cranes where the pin carried much of the weight of the superstructure and load
Lattice Jib Jib of generally open construction; sometimes referred to as "Double Latticed"
Leeds Crane Early type crane with vertical engine and with superstructure located by combination of tall centre-post and bottom two-part slewing ring
Live Race Three-part slewing race with conical rollers for supporting the superstructure (See also “Roller Path”)
Load Moment The product of the load and radius.  In crane terms, the load moment is likely to be greatest when lifting the maximum design load at the minimum working radius and will generally be expressed in ton-foot (obsolescent) or tonne-metre
Load/Radius The limit of load that can be carried at any particular radius from the centre pin
Luffing As “Derricking”
Main Block As “Bottom Block”
Match Wagon A wagon included in a train so as to allow two vehicles to be coupled together when this would otherwise be impossible, for example a flat wagon located beneath an overhanging load.  The term is also frequently albeit imprecisely used in place of  "Jib Runner"
Outreach Maximum distance that the hook can extend from the extreme end of the carriage
Outrigger Extending or hinged crane support beam; the extending type is more often termed “Prop” or “Girder”
Packing Support placed under each prop to spread the load over a larger ground area
Portée Distance from front of crane to minimum radius of the hook
Prop Support beam extensible from the crane carriage (see also “Outrigger” or "Beam")
Propelling The act of moving a crane under its own power.  Also known as “Travelling”.  Note that the term “propelling” has a different meaning in other railway operations
Prop Jack As “Prop Screw”
Prop Roller Free-running roller fitted to carriage under each prop to assist sliding in/out
Prop Screw Bearing screw at the end of the prop, for winding down onto packing
Pulley A grooved wheel that drives, or is driven by, a concentric means such as a shaft
Rail Clip Split clamp attaching crane to rail for increased security in heavy hoists
Rail Dog See “Rail Clip”
Ramshorn Double hook for heavy duty hoisting.  Alternatively: "Ram's-horn"
Reeving Act of installing a wire rope
Relieving Bogie Truck taking some weight off the crane to reduce axle loads for running in a train
Relieving Screw Screw above spring clamp on crane carriage; wound down before raising jib to prevent the spring from taking any of the weight of the jib or burden so as to (a) protect the spring from overload and (b) improve the stability of the crane.  Earlier cranes used wedges rather than screws
Return Block As “Bottom Block”
Roller Path Ring carrying load from rollers in a slewing race (either two-part or live)
Runner Jib Runner.  (See also "Match Wagon")
Safety Chain Auxiliary coupling chain at one time fitted in pairs to rolling stock.  Were often fitted between the crane carriage and jib runner.  Notably, were fitted to the final three 30-ton cranes built by Cowans Sheldon for the LMS in 1943 and to their 30-ton cranes for BR in the 1960s, all of which had articulated jibs
Scotch Wedge placed against wheel tyre so as to hold vehicle from moving
Sheave A free-running grooved wheel mounted on a shaft or spindle
Signaller See “Banksman”
Slewing Act of rotating the superstructure about the centre-pin or post
Slewing Pinion Small driven gear which, by means of its engagement with the Slewing Rack, is used to slew the superstructure of the crane
Slewing Rack Large spur gear fixed to the carriage and used in conjunction with the Slewing Pinion to slew the superstructure
Slewing Ring Machined circle complete with rollers in either two-part or live race.  The term "Slewing Ring" is sometimes used colloquially in lieu of "Slewing Rack"
Slew Lock Also known as a Tail Lock.  Spring-loaded device fitted to rear end of crane carriage, engaged prior to running the crane in a train so as to limit superstructure slew when negotiating curves in the line and to ensure that the tail of the superstructure remains in gauge.  Some early cranes achieved the same result by means of chains constraining the movement of the jib head relative to the jib runner
Slinger Person responsible for attaching slings to the burden to be hoisted
Sole Plate Main constructional part of the crane carriage, on which the Centre Pin is mounted
Spear Shaft Vertical shaft passing through Centre Pin to transmit crane self-propelling motion
Spreader Beam Beam with fitting at each end so as to maintain two slings in a vertical mode
Spring Lock As “Relieving Screw”
Spring Screw As “Relieving Screw”
Stokes Bogie As “Relieving Bogie”
Strut Jib Fixed length jib, i.e. non-telescopic
Superstructure That part of a crane which revolves around the centre-pin or post and includes the driver's platform, boiler, engines, gearing, rope drums and jib pivot
Tail Jack Screw jack on top of the carriage, engaged to support counterweight when running the crane in a train so as to prevent shock damage to the roller-race and centre pin
Tail Lock As “Slew Lock”
Tailweight As “Counterweight”
Tag Line Controlling rope tied to the burden, the loose end either held by a man on the ground or, especially where the crane is to travel with the burden, securely tied to the crane
Travelling The act of moving a crane under its own power.  Also known as “Propelling”
Travel Clutch Generally comprising two spur gears, driving and driven, situated below the carriage and able to be moved in or out of engagement by means of handwheels
Winching Chain Chain used to haul the bottom block assembly into its stowage location on the jib runner (not needed where the runner has a sloping floor equipped with rollers for the block to be taken down by gravity)
Working Radius Horizontal distance from the centre of rotation of the superstructure to the centreline of the lifting hook