shopmate: workmate (shop in this context means  workshop as distinct from retail shop) 

One employed to move a train or some portion of it from the main line to a side-track or from one line of rails to another; 

Shunt: To move (a train or some portion of it) from the main line to a side-track or from one line of rails to another; also to move back. [OED]

An instrument used in weaving for passing the thread of the weft to and fro from one edge of the cloth to the other between the threads of the warp.
Snarl To tangle; to twist together confusedly; to make a tangle of.
Roved to make (carded or combed wool, cotton, etc.) into rovings (A long thin strand of wool or cotton, drawn out and slightly twisted in preparation for spinning; a roll of this. [OED]

in which it difficult to establish and maintain the necessary pressure

King James bible Amos 9:9  "For, lo, I will command, and I will sift the house of Israel among all nations, like as corn is sifted in a sieve, yet shall not the least grain fall upon the earth."

A type of bannock, griddle cake or scone, made in the north of England, especially Northumberland and the coal-mining areas of the North East. In Scotland, they are known as fatty cutties. Wikipedia. They make a hissing sound when cooking [OED]

The gap between the running lines carrying traffic  (as distinct from the area between the parallel rails that constitute the running line known as the "4 foot")
[RMweb - accessed 26Sep2019]

A coin worth six old pence or cash to that value [CPB]

Meaning unknown. Possibly a hat.

 Schoolboard:  A body of people, typically elected, responsible for the provision, maintenance, and administration of schools, or for determining educational policy [OED]

a very large, flat, cartilaginous fish much used for food. [OED]

Skiff - A small sea-going boat, adapted for rowing and sailing; esp. one attached to a ship and used for purposes of communication, transport, towing, etc. Hence, a small light boat of any kind [OED]

Gin [OED]

small or refuse coal [OED]

Possibly Slate Coal, a hard, dull variety of coal [OED]

Short for “Slap-Up”; very good or fine; of superior quality, style, etc.; first-rate, first-class, grand. Common in the 19th century.

Very good or fine; of superior quality, style, etc.; first-rate, first-class, grand [OED]

Very large or fine; splendid [OED]