Sand quarrying firm J. Arnold & Sons Limited used the Leighton Buzzard Light Railway from its opening in 1919 until it closed as a working railway in 1982. The railway conveyed the sand to Billington Road where most of it was washed (some quarries had small washing plants on site). From 1986 the washing took place at the closed Double Arches pit in Heath and Reach. Main line railway sidings were also located at Billington Road connected, via the Leighton Buzzard to Dunstable railway, with the main line from London to Glasgow.
The washing plant was, in 1934, driven by a Crossley 40 horsepower gas engine and a suction gas plant. Town gas was used to fire up the plant but was then shut off and gas from the producer used to keep it running. The arcane description of the plant and the process given in Cement, Lime & Gravel was as follows: "The plant itself consists of three single barrel washers on the Rikof principle with dewaterers and improved double barrel washer made to the Firm's design. This design, arrived at by experience, gives more efficient washing and a larger output. Below the washers are two shingle screens, in which shingle, eliminated from the sand, is rewashed and screened".
"The operation of the washers is very simple. the long slowly rotating barrel of the washer is fitted with interior helical vanes which frequently turn the sand and run off the water so that, by the time the sand has passed to the short shingle screen at the end, whatever silt there is, is thoroughly wet and is more or less in suspension in the water".
"The sand and water fall to the dewaterer which is conical in structure, having the major axis horizontal. The exterior of the cone is fitted with long troughs and is slowly rotated about its horizontal axis. The effect of this is to collect water and sand in each trough as it becomes horizontal on one side, then as the trough rises, the one end is slightly tilted and the water and silt is gently run off at the narrow end of the cone, the sand settling in the trough. As the trough passes over the top and down the side opposite to the feed the clean sand is discharged into wagons standing beneath the cone"
"Water for working is drawn from a large pool immediately in front of the plant. This pool, which is an old sand quarry, was excavated by crane grabs and is, consequently, deep and fairly even in depth. It makes a large reservoir, giving an ample supply of clean washing water".
"The pumping installation is a three inch centrifugal pump, made by the Centrifugal Pump Company, and capable of 200 gallons per minute. This delivers to one 2,000 gallon storage tank and to two smaller tanks. A horizontal Tangye pump is kept as a standby for emergencies".
"The sand to be washed is tipped at the topside of the plant to the foot of the three bucket elevators feeding the single barrel machines and, in the case of the improved washer, into a hopper feeding the belt conveyor which serves it".
"The washed products, discharged into the tip wagons beneath the machines, are hauled to a gantry above the main line siding to be tipped into wagons for despatch".