Staff

Staff may refer to:

Rods

Token (railway signalling)

In railway signalling, a token is a physical object which a locomotive driver is required to have or see before entering onto a particular section of single track. The token is clearly endorsed with the name of the section it belongs to. A token system is used for single lines because of the very much greater risk of serious collision in the event of irregular working by signalmen or traincrews, than on double lines.

Principle

The operation of a bidirectional single track line has obvious problems, the most serious of which is the possibility of two trains traversing the line travelling towards each other, each driver unaware that the other is using the line. The simplest method of controlling such a line is to have only one engine operational, on the basis that a single train cannot collide with itself, and in the absence of another engine, there is nothing else for it to collide with. Such a system is known as "one engine in steam". Such schemes were used, and indeed still are used on some branches of rail networks, and on heritage railways. The main problem with such a scheme is that it is best suited to a completely isolated branch of single track line. Where the section has to be integrated into a larger railway system, it becomes exceptionally limiting in the level of operations that it allows, and the opportunity for a mistake to be made, and an ensuing accident to occur, is high.

Staff (building material)

Staff is a kind of artificial stone used for covering and ornamenting temporary buildings.

Staff is chiefly made of powdered gypsum or plaster of Paris, with a little cement, glycerin, and dextrin, mixed with water until it is about as thick as molasses. When staff is cast in molds it can form any shape. To strengthen it coarse cloth or bagging, or fibers of hemp or jute, are put into the molds before casting. It becomes hard enough in about a half hour to be removed and fastened on the building in construction. Staff may easily be bent, sawed, bored, or nailed. Its natural color is murky white, but it may be made to resemble any kind of stone.

Staff was invented in France about 1876 and was used in the construction and ornamentation of the buildings of the Paris Expositions of 1878 and of 1889. It was also largely used in the construction of the buildings of the World's Columbian Exposition at Chicago in 1893, at the Omaha and Buffalo Expositions in 1898 and 1901, at the Louisiana Purchase Exposition in 1904, and at later expositions and on temporary buildings of other kinds.