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Salt


When Sir Humphrey Davy first separated salt into its constituent parts of sodium and chlorine in 1807 no one had any use for either. Today salt is one of the more important chemicals in industry, chlorine is used to make hydrochloric acid, sodium hypochlorite and forms part of several important chemicals (notably PVC or poly vinyl chloride). Sodium is used to make various compounds such as sodium carbonate (soda), sodium sulphate, baking soda, sodium phosphate, and sodium hydroxide. Salt is widely used as a preservative for meats and is employed in some refrigeration processes, in dyeing, and in the manufacture of soap and glass. Salt crystals (transparent to infra red) are used as lenses for some laboratory imaging systems.

Cheshire is by far the most important salt producing area in the UK, and has been since the Romans exploited its 'brine springs'. Cheshire was served by the LNER, LMS and GWR, all of whom would therefore have taken both salt and its related chemicals traffic. The rock salt deposits extended North into Lancashire and in the 17th century several mines were set up on the banks of the Mersey near Liverpool to exploit these particularly pure salt deposits. This lead to a thriving coastal traffic in salt from Liverpool, hence the works were mainly built along the banks of the river. The canals and later the railways allows salt to be easily brought in from Cheshire to be loaded onto ships in Liverpool docks.

I used to own an 'OO' gauge Wrenn 7 plank salt wagon in Jas Colman livery, a firm based in Liverpool but about which I have not yet traced any information. The design was common for salt wagons, about seven planks high, cupboard doors and a simple pitched roof. Wrenn produced several variations on this companies livery, but I cannot comment on the accuracy of any of them.

Fig ___ Wrenn livery for Jas Colman Salt Wagon

Sketch of Jas Coleman wagon

It should be noted that a lot of industrial salt was transported in bulk in standard mineral wagons, presumably sheeted in transit.

North Lancashire was once a major salt producing area (up to the early 20th Century at least) and salt mines were also operating in Staffordshire, Worcestershire, Yorkshire, Durham and the Isle of Man (Point of Ayre). The most important salt producing areas in the UK were Northwich, Middlewich, Winsford and Sandbach in Cheshire, Weston-on-Trent in Staffordshire, Stoke Prior and Droitwich in Worcestershire and Middlesbrough in Yorkshire.

There were also one or two coastal salt works producing 'sea salt', either evaporating seawater or tapping wells into salt marshes to extract the brine. One example was at St David's on the Firth of Forth, this started life as a sea salt works but when the salt tax was repealed in the 1820s the economics changed and they switched to bringing Cheshire rock salt in by sea and refining this using the cheap local coal supplies. Hence you could justify a salt works for just about any coastal location, although finding suitable liveries on RTR rolling stock might be tricky. The buildings required would be as for the inland salt works.

As with any mining activity if nothing is put back the earth above will eventually subside, things got so bad that in the later 19th century laws were passed to provide compensation for home owners sufferng salt related subsidence. In Cheshire, where the salt beds are about a hundred feet thick, the Victorians built timber framed houses that could be jacked up if the land subsided unevenly beneath them. The photo below was taken in Northwich, and area of Cheshire where these buildings are very common, inclusion of similar structures on a layout would help set the location for the works.

Fig ___ Timber framed buildings in Northwich
Photo showing timber framed buildings





Production Methods

The methods of mined salt production remain much the same in principle today as those employed by the Romans; it is typically 'mined' using water to dissolve the rock, for small scale production you sink a well and allow the ground water brine to collect, this being replaced naturally by rain water. In the North East however the salt was very deep and rain water did not penetrate that far, so they had to drop a double pipe, rain water was directed into the outer pipe and the resulting brine extracted from the inner tube.

In some locations (Cheshire and Durham) they also sank conventional mines and extracted rock salt directly using the 'room and pillar' method. In the early 20th century they used gunpowder to break up the salt beds, by the 1960s they were using mining machenery (however I am not sure when this was introduced). In more recent times these mines have supplied the road gritting salt used by local councils.

Pumping brine was by far the most common method of production, most works pumped the brine into a large open topped holding tank, from which it was piped to the drying pans as required. If visiting the Lion salt works the large water tanks by the canal side is the brine tank.

Various impurities in the salt such as magnesium and calcium are removed by precipitating them in this brine stage using milk of lime (calcium hydroxide suspended in water), soda ash and boiler flue gas, the resulting waste is these days returned to the brine cavities to prevent subsidence.

The resulting purified brine is then dried to produce salt crystals. Originally this drying was done in large heated drying pans open to the air but in 1905 the first vacuum evaporation plant was built by the Salt Union at Winsford. This uses a closed chamber from which the air is pumped, this lowers the boiling point of the water so much less heat is required to dry the salt. This system is now the standard method of industrial refining the material, variations in the process enabling a wide range of grades to be produced.

Having said which the last open pan works, Lion Salt Works near Northwich, only ceased production in the later 1980s!

A lot of salt works had an attendant chemical works, mainly making soda but also producing soap and other salt related products. Industrial users can take salt with about 25% water, food production however requires salt which has been completely dried. This is done in large ovens at the works.

Due to the problems of corrosion and contamination table salt is usually shipped bagged rather than in bulk. Salt was shipped in white cloth bags up to the 1940's, these were about two foot six high by a foot wide and tied off at the top. Each held 40 lbs of salt. Table salt was also shipped in paper packets, ready for distribution to grocery shops for sale.

In the post war era the main use for salt has been for softening hard water, followed by industrial users with table salt and processed food factories being a comparatively small part of the overall business.

Salt for industrial purposes was usually loaded in bulk into standard open wagons (presumably sheeted in transit) but some was formed in to blocks about two feet long by nine inches square which could be easily manhandled and moved about the works on a simple L shaped 'brick barrow' (as also used in brick and tile works).

Fig ___ Barrow for use in a salt works
Sketch showing typical wooden brick barrow




Modelling a Salt Works

The Lion Salt Works in Cheshire was the last open pan salt works in the UK, it only ceased operating in the 1980's and is now a museum. This is worth a visit if considering a small salt works for a layout.

As mentioned above the salt making process consists of pumping brine from a deep well and cleaning this with chemicals to remove impurities. The depth of the well depends on the depth of the salt bed, in Cheshire they can be as shallow as a hundred feet, in the North East they are over a thousand feet down.

The shallow type of well can be accessed with a brick lined shaft but for deeper deposits the American 'cable tool' drilling rig was used. Based on an ancient design of bamboo drill the modern form was developed in the very early 19th century (about 1825). The drill works by lifting and dropping the drill bit under its own weight (to break up the ground) and as it moves down a liner is inserted to hold the hole open once the drilling is complete. The process is slow, but cheap, and it soon became the standard way of drilling deep water wells and brine holes for salt production.

The drill was operated by something resembling a beam engine, the drill being suspended from one end of the rocking 'walking beam'. The tower was there to allow the drill to be lifted clear of the hole and a bucket type device lowered in to collect the waste. Once the well had reached the required depth the rocking 'walking beam' mechanism in the base of the drill was easily adapted to pumping water and the redundant derrick tended to be left in place.

The sketch below is based on a photograph of the old all-wooden tower at the Murgatroyds salt works at Middlewich in Cheshire in the mid to late 19th century. The tower is pleasantly simple and could be made up from Plastruct strip or strip wood without too much difficulty. The original drilling mechanism appears to have been removed in this example, but the tower was retained for pumping. The rod of the pump can be seen suspended in the centre, in use this would rise and fall on about a four second cycle.

Fig ___ Brine pump tower

Sketch of a brine pump tower

Access is via a series of wooden bars attached to one of the legs (on the left in the illustration), a ladder may well have been fitted by the 1930s, but possibly not. I believe examples of these wooden pump towers remained in place at some locations up to World War Two (possibly shortly after) although I understand that many works had switched to smaller pumps contained in a building by then. Older photos of 'oil fields' often show this kind of tower, in both wood and metal, try a search for 'oil derrick'.

The metal framed example shown below was a deep well American desined rig at the Cerebos works at Greatham in the North East. Several of these were set up in the 1880s and operated until about 1970 (but only one (semi derelict) survived into the mid 1970s). There are two drawbacks with this style of pump, for a start it is a bigger structure, and secondly modelling the metal tower would be deeply tedious unless you can find a suitable etched tower (such as the Scale Link water pump tower).

The sketch is based on a photograph I found on the University of Newcastle SINE project website (recording industrial structures of the North East).

Fig ___ Metal brine pump tower

Sketch of a metal brine pump tower

The original equipment used to drive the drill was in this case retained and re-used to drive the pump, hence the building around the base of the tower. This structure was often quite open (the pump operated largely unattended), the roof was usually there but there were often large openings in the sides and ends. If considering modelling a rocking beam pump, with the associated drill tower, the sketch below shows the basic features you should include. I have drawn this to represent a smaller example and have shown a figure to give a sense of scale.

A, B and C are drive shafts used for winding various cables during the drilling, they were sometimes simply left attached to the structure as shown (the shafts of B and C are run between the derrick legs). The drive wheels of these three should all be aligned with the second drive pulley on the engine (one each side of the engine crank), they could then be belted up and used as required.

Fig ___ Arrangement of parts

Sketch of a brine pump tower and parts

Not all salt works pumps had the derrick type towers, some used more conventional pumps in a pump house, in some cases an older wooden tower type pump was demolished and replaced with a more modern pump in a pump house. The derrick is a more interesting thing to have as a model, but a pump house is a lot easier to make. A typical pump house would be about twenty feet long and fifteen feet wide with a large door or doors for access. They were often quite tall for a 'hut', with side walls perhaps ten feet high. The sketch below is based on the surviving pump house in Droitwich.

Fig ___ Brine Pump House

Sketch of a brine Pump House

This building houses both the pump and its associated motor used to supply the local Spa (you could get away with something slightly smaller for a salt works). This building currently houses an electric pump motor, for an oil, gas or heat engine you need to add a chimney (this can be a simple 'stove pipe' tube type).

The brine pumped from the well is first placed in a large holding tank, the sketch below is based on the tank at the Lion salt works in Northwich, the figure gives a sense of the scale. The tank at the Murgatroyd works in Middlewich was a similar size but sat on a taller base (about fifteen feet high) and had the company name painted on the side visible to passers by.

Fig ___ Brine tank

Sketch of a brine tank

Pipes take the brine from the tank to smaller tanks where the impurities are removed by precipitation. The soda ash and milk of lime (used to precipitate the impurities) would leave some white staining in areas where they were handled, but salt dissolves so do not go overboard on the stains.

The brine is then passed to the evaporators, either heated open pans or heated sealed vacuum chambers (which need less heat). Here most of the water is driven off, industrial users would be content with this damp salt but for food use it was further dried in ovens. Chimneys were therefore a characteristic feature of salt works.

The basic salt works would have storage tanks for the brine, buildings for the evaporating pans or chambers, buildings housing the drying stoves, warehouses for the salt and a small office building.

A typical salt works consisted of a series of large but low single storey buildings with a shallow pitched roof and a number of not very tall chimneys. These buildings housed the shallow salt pans to one side, with the fire boxes beneath. The opposite side was where the salt, recovered from the pans, was dumped ready to be dried and bagged or formed into blocks. Industrial grade salt was just shovelled into open wagons for delivery to chemicals companies, soap factories and glass works.

Fig ___ Cross section salt pan building

Sketch of cross section salt pan building

There were usually a couple of two or three storey smaller buildings on the site, presumably housing the bagging stores and offices. A boiler house would be needed for the brine pumps and (at works built or rebuilt after 1905) for the vacuum pumps at the works.

For a model railway layout the best option would presumably be to model the large, low roofed buildings against the backscene with the taller buildings to one or both ends and the siding(s) running across the front. The chimneys seem to have been generally placed at the outer wall, however by placing them on the roof as shown below they are out of the way and will not cast a shadow on the backscene. Many of the salt works were extensive, quite a few had an associated chemical plant on site, the example sketched below is about as small as you can get away with for a layout (about eighteen inches long in N, three feet or so in OO).

Fig ___ Example salt works plan for a model railway layout

Sketch of example salt works plan

Note the roof ventilators on the building containing the salt pans and drying ovens, there were often a number of openings in the walls under the eaves as well. Assuming an 'open pan' system is in use you can add the fire holes under the brine tanks to the outer wall (as suggested on the sketch). These were often tucked under the eaves of the roof as shown in the cross section above, the sketch below is based on a photo from the 1930s.

Fig ___ Feeding the salt pan fires

Sketch of man feeding the salt pan fires



No 'brine pump' or 'brine tank' is shown on the suggested layout sketch, they can be fitted-in where space allows. In some cases the pump tower or hut was located some distance from the large tank, connected by a fairly thick pipe. For a pump tower not having the original building around the base and not using the walking beam you need a small associated building to house the engine operating the pump cable. The engine itself might be almost any type, I have found references to hot air, oil, steam and gas engines. Steam could be piped in from the main works boiler or it might have its own small boiler (this is less likely I suspect and requires a larger building).

The brine tank should be at least twenty feet long, ten feet wide and typically about six feet deep, mounted on a low structure (the bottom of the tank needs to be at least level with the eaves of the salt pan building). A model railway water tank (on a lowered base) would do, although these are a bit on the small side for a salt works and a plain tank with vertical ribs along the sides as shown above is all that is required. Some firms had their name emblazoned on the side of this tank if it was visible from a road, railway line or canal.

If space allows a few additional buildings would help, a stables would be likely, and a cart shed-cum-workshop, but just a couple of generic huts helps make the place look busy.

The salt was usually loaded from raised loading banks, or directly from the building via large doors as shown on the sketch below left. The openings in the wall would also be useful for loading dried (bagged) salt into salt vans to keep it clear of the rain. Bulk salt for industrial uses was shovelled into open wagons from small hand carts, either from a raised loading bank or through openings in the side of the building beside the siding. Note the hand cart shown far right has metal straps with loops on the ends so it can be handled by a crane.

Fig ___ Hand carts as used at salt works

Sketch of hand carts as used at salt works

I made a similar size hand barrow for a small builders yard, the body is folded postcard, the wheels are press studs and the handles and supports are bent up from wire. The result is not at all 'fine scale, but at anything over two feet it passes muster for 'set dressing' (in the yard it sat in a corner, not out in plain view).

Fig ___ N scale home made hand cart

Sketch of a home made hand cart as used at salt works

The men working inside the works, in high heat and humidity, were more often than not stripped to the waist (sweat soaked salty clothing would chafe as they worked). There are not many commercial figures stripped to the waist, but you can start with (for example) Preiser 'men in swimming gear' and build up the trousers using PVA or acrylic varnish before painting. Wellington boots (and before that tall leather boots of similar appearance) were commonly worn by the men wotking with the brine.

Incoming cargo would be coal for the heating system and steam boilers (for the brine and vacuum pumps), for the purification process there would be barrels of 'milk of lime' and either wagon loads of bulk soda ash or wagon loads of the stuff in sacks. The LMS and BR (and possibly others) built special wagons for soda ash, the example shown is a BR bult wagon (based on an LNER design) modified for soda ash traffic.

Fig ___ BR soda ash wagon

Sketch of a BR soda ash wagon



Outgoing would be table salt in cloth bags or industrial salt in bulk or in blocks about two feet long by about 9 inches square (30cm x 8cm x 8cm).

Industrial salt was often shipped in standard open wagons, however several companies used low-roofed vans for their salt, typically with a simple pitched roof (known as 'cottage topped wagons' by railwaymen). These were typically a standard 7 or 8 plank open wagon fitted with cupboard doors and the pitched roof (this allowed them to use standard wagon parts such as corner plates, easing maintenance). On some there were strips on top of the roof (from bottom to top) to stop the nails holding down the canvas cover from penetrating the wagon and tearing the bags (not all salt wagons had these strips).

The ornate liveries seen on salt vans were I suspect mainly confined to wagons carrying table salt, the industrial stuff did not benefit much from advertising to the general public in this way.

There are several 'salt wagon' models available, the Saxa yellow and red 'non pool' livery is I believe accurate (there is a preserved example at the Bo'ness & Kinneil Railway in Scotland in this livery, they used traces of paint found on the wagon body to get the colours right).

Fig ___ PO Salt Wagon

Sketch of Saxa wagon

Saxa Salt was a brand of the Cerebos salt company (founded in 1884 in Newcastle). The “Saxa” brand was launched in 1907.

Some of the early salt wagons had a curved roof, similar to those on railway goods vans, but this must have been more expensive and the simple pitched roof seems to have become the norm (pitched roof mineral wagons were a standard product, used amongst other things for transporting coal dust).

Fig ___ Early (curved roof) 'Salt Union' Salt Wagon

Sketch of 'Salt Union' wagon

I have seen a photo of bagged salt being unloaded from a Salt Union liveried standard 5 plank open wagon in the very early 20th century. The bags themselves were branded and a man in the wagon was handing them down one at a time to two men loading a horse drawn van. The livery shown below is something of a guess as the left hand of the wagon was partly obscured, although I do remember reading somewhere that their wagons were originally painted grey.

Fig ___ Salt Union open Wagon

Sketch of Salt Union open WagonSketch of salt bags being unloaded from an open wagon

For open wagons, such as those carrying 'industrial' grade salt, the top of the Peco wagon can be removed and replaced by a tarpaulin draped over the wagon.

In the BR era a number of fitted (vacuum brake) and unfitted 25 ton iron ore wagons of the type offered as a kit by the N Gauge Society were converted for industrial salt traffic (there are photographs on Paul Bartlett's 'fotopic' site - see Bibliography, photo sites). In service these were sheeted over. These would run to a larger salt works and supplied industrial users.

In the 1970s some PGA type hopper wagons were built and leased by Procor for salt traffic, they were still in use in the later 1980s although they suffered once more from the corrosive effects of the salt.




Related Industries

There might also be a chemical plant associated with the works, these mainly produced soda (Sodium Carbonate, often called Alkali although it is only one of many alkalis). An example would the Stafford Salt and Alkali Co Ltd, who sold 'Snowdrift' brand table salt as well as soda. Soda is made using salt and sulphuric acid and some works had their own sulphuric acid 'chambers' on site, other brought the acid in (an excuse for running acid tanks on the layout). The resulting material is then burnt with lime mixed with coal (brought in using open mineral wagons and roofed or sheeted lime wagons). Soda works produced nasty by-products and favoured very tall chimneys, later supplemented by 'washing towers'. For more on soda works see 'Lineside Industries - Chemicals and Related Industries'. The main part of the soda works would be occupied by large buildings housing the furnaces, with the attendant chimneys.

Fig ___ Typical LeBlanc works

Sketch showing a   typical LeBlanc works, St Rollox, Glasgow, circa1880. This image is in the public domain
This image is in the public domain



A chemical works for soda manufacture can justify acid tank wagons, which is handy, if the acid were made on site they would need large rectangular vitriol chambers with attendant, pyrites furnaces, boilers, engines labs etc. For more on sulphuric acid works and their buildings works see 'Lineside Industries - Chemicals and Related Industries'.

Some salt works also had an adjacent soapery although these tended to favour coastal locations where they could import the necessary oils (supplied in large barrels). If included this establishment would have a series of large buildings housing the 'coppers', soap frames, crystallising pans, iron vats, pumps etc.

Fig ___ Palm oil casks as seen in soap and margarine works

Palm oil casks as seen in soap and margarine works

For more on soap manufacture see also 'Lineside Industries - Industries associated with Docks & Harbours'.




Salt Producers

Historically there have been a great many salt producing companies, both small and large, but things settled down in the hard times of the later 19th century. During the 20th century there was a continued rationalisation, with firms merging to form larger organisations.

In Britain today (mid 1980s) there are two major salt producers, ICI and British Salt, both base their salt production on the Cheshire plain. The Romans first exploited the salt deposits of Cheshire on a commercial basis, the town of Middlewich was called 'Salinae' which actually means 'salt works' and all the towns who's names end in 'wich' are connected with the salt industry.

The history of the firms involved in salt production really starts in the middle of the 19th century, when demand was booming and a great many small firms set up. This lead to the usual problems of over capacity and fierce competition as the growth in demand began to tail off towards the end of the century.

The discovery of salt deposits was usually accidental, in Stafford they were trying to find a source of fresh water for the town when they found a substantial salt deposit. The Stafford Salt and Alkali Co. (founded in 1893) was the first to open on the site and operated two works, the British Soda Co set up a chemical works nearby to use some of their product. The Stafford Salt and Alkali Co. were followed by Crown Saltworks and a works operated by the chemical company Chance and Hunt.

Fig ___ Chance & Hunt salt wagon

Sketch of a Chance & Hunt salt wagon

The area around Droitwich had a salt industry since Roman times, based on extracting the briny ground water and evaporating this in pans. The town became a spa in the 19th century, people did not drink the briny water but swam in it. In about 1830 a major deposit was discovered at Stoke Prior were found. This provoked substantial investment in new works. The British Rock And Patent Salt Company, founded in the 1820s, became Imperial Salt & Alkali Co in 1835 and ended up as part of the Salt Union in the 1880s (see below). The works were extensive, initially producing salt, soda, vitriol (sulphuric acid) and soap. A branch line was run into the works in the 1840s and the works itself operated a fleet of three locomotives and a large number (over 400) of its own railway wagons and vans (maintained at workshops on the factory site). There were also extensive narrow gauge lines in the works, worked by men and possibly horses. The branch linked into what became the Great Western Railway system.

The mighty Salt Union was formed in 1888 when 64 of the salt firms (accounting for some 90 percent of the UK total salt production) banded together. The Union acted as a regulatory body somewhat similar to OPEC and funded research and development into production methods, such as the vacuum drying process mentioned above.

Individual company names and brands seem to have continued in use, Salt Union wagons often have the original salt brand name on them, and the mention of the union varies in size and placement (there seem to have been only a few in plain Salt Union livery). Presumably each of the small firms in the union continued to order its own rolling stock and specified the paint job required. The examples below are two variations on the Falk Salt livery.

Fig ___ Falk salt wagon

Sketch of a Falk salt wagon

The Salt Union was not all encompassing, there remained a number of smaller firms in scattered locations and a couple of quite large concerns. The large and independent Cerebos salt company was founded in 1884 in Newcastle, their “Saxa” national brand was launched in 1907.

Fig ___ Cerebos enamel sign

Sketch of Cerebos enamel sign



An example of a coastal salt works is the 'Fleetwood Salt' factory (a wagon for which is shown below in early ICI livery). This started life as a collection of small sea-salt open pans on the banks of the River Wyre in Lancashire. In the mid 19th century they sank wells into the salt marshes and extracted the brine for evaporation. Toward the end of the 19th century they built a works at Presall on the opposite bank of the river, supplied with brine pumped via pipes from the salt marshes on the opposite bank. The Garstang & Knott End Railway laid in a siding and by the start of the 20th century the factory was also making 'soda'. They were taken over by ICI, who almost immediately closed the salt works (in the mid 1920s), but the chemical plant remained in operation into the 21st century.

In 1937 the Salt Union was acquired by ICI, who then became the UK's major supplier of salt. Initially ICI used their full name (Imperial Chemical Industries) on the wagon sides.

Fig ___ ICI Salt Wagon (early livery)

Sketch of ICI salt wagon

I believe this then changed to I.C.I in white lettering, shaded black, generally about 18 inches (45 cm) high. Note than on some wagons there were full stops after the first I and the C (I.C.I). Having said which they dropped the full stops on most wagons and there seem to have been a number of variations in the livery, some having a simple 'return empty to' branding in the lower left, others having the name of the salt works across the top of the wagon side.

In this period ICI's salt stock (both wagons and vans) was painted cherry red with the ICI spaced centrally on the body and, in the case of the salt vans, the word SALT about a foot high to the lower right. The ICI circular 'logo' appeared (I believe) just after World War two) and was thereafter used on all ICI rolling stock.

When ICI de-merged they sold off their salt industries in about 1991, which became a re-born Salt Union Ltd. This company, based at Winsford in Cheshire is the major supplier of road gritting rock salt.

After the second world war many of the remaining firms merged, two of the largest being Cerebos (who own Saxa) and Stavely Industries, who set up a joint operation in the mid 1960s.

Stavely Industries had been involved with salt (as an industrial chemical) since 1923 when their British Soda subsidiary built a manufacturing plant at Sandbach. The new joint company built a new plant at Middlewich, next to the existing Cerebos packing plant and became 'British Salt Ltd' in 1967. Shortly after this Rank Hovis McDougall organisation acquired Cerebos and in 1982 they sold their share of British Salt to Stavely Industries, who then became sole owner.

A company called Vacuum Salt Co was operating by the 1940s (they purchased one of the Stafford salt works in 1949). In 1950 several firms in Stafford merged to form Amasol Ltd, which was then taken over by British Soda Co.

In the post war era ICI operated a fleet of Pressflo wagons modified for salt traffic in a green livery (illustrated in the section on Livery - Livery PO wagons). These were used to carry salt from Stoke Prior (near Droitwich Spa) to Winsford in Cheshire, probably in block trains. Stoke Prior ceased salt production in the mid 1960s, after which the wagons ran for a time based in Cheshire and were (I believe) sold or leased for fly ash traffic from power stations.




Rock Salt for Road Gritting

Raw salt, straight from the mine, is used to 'grit' roads when there is a danger of ice forming on the surface. Rock salt is not mined using water, it would have to be dried and the impurities do not need to be removed, it is extracted using a machine which tears at the face of the deposit. It emerges from the mine as a rough light pinkish grey granular material and it (typically) stored in a large building consisting of a roof sitting on the ground and generally handled using a 'front loader'.

Cleveland Potash mine potash in the North East, however about 25 precent of the stuff from the mine is actually salt. In the early 1980s they began selling this rock salt to local authorities for winter road gritting. One problem with this traffic was that the salt tended to corrode the metal of the wagon or container, so PO stock was used for the traffic. They shipped the salt by rail in modified air-braked hopper wagons and in open topped Cobra containers.

There is also an extensive rock salt mining operation in Cheshire to supply the road gritting services, however as far as I am aware this plant does not use rail transport.



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