Steam loco limescale

[bluesparkdave]

In which areas of the UK was limescale staining of steam locos more prevalent?

[The Johnster]

Broadly speaking, those where water supplies were obtained from 'hard' groundwater in areas with calcareous bedrock, i.e. limestone and chalk.  So, the North & South Downs, Salisbury Plain, Dorset, the Chilterns (which supply artesian water to London), Bath, Bristol, and the Mendips, the Cots, Lincolnshire, and Yorkshire Wolds, parts of South and North Wales, Forest of Dean, Peak District, Lancashire, Yorkshire Dales, South Yorkshire, parts of Shropshire, North Yorkshire Moors, Upper Clyde Valley.  Not far off half the country, the 'hard water' areas where you get limescale in your kettle.  If you pour vinegar or wine, acetic acid, on to any of these rocks, they will fizz and dissolve quite vigorously in the acid.  If they don't, they're not calcareous, which in the British Isles means they are not Limestone or Chalk. 

 

As a brief explanation, that'll prolly do, and you can go and do something else now, but there's more if you want it.  You know the them tune for 'Big Bang Theory'?  Well...

 

Very briefly, a little after the point in the theme tune where the 'achitropes began to drool' but a long time after 'the earth began to cool' what happened was that about 60 million years ago, the tectonic plate carrying Africa collided with that carrying Europe, a collision that is still ongoing and that made a crumple zone of rocks that formed the mountain ranges of Southern Europe, Sierra Nevada, Pyrenees, Alps, Carpathians (and the Atlas of North Africa) by folding the beds of rock upwards and downwards.  Futher away from the collision, northwards and westwards, the folding was less dramatic, the result of those big mountain ranges being pushed further in that direction, but it is still the reason for the predominantly SW-NE alignment of folded rocks in the UK south and east of a line very roughly from Exeter to Newcastle, and most of Wales, where faults follow this alignment.  This is what is known as the 'Alpine Orogenesis', a period of mountain-building still in progress.  Many ages prior to this, there was another one called the 'Hycernian', which accounts for the W-E alignments of rock strata in West Wales, Devon, and Cornwall. but these rocks were once buried very deep in the crust and there are areas of solidified magma in the form of granite which melted it's way up through the crust from the mantle beneath and probably fed major volcanoes until the tectonic plate moved away from the hotspot and it gradually cooled (Exmoor, Dartmoor, Bodmin Moor, West Cornwall, The Scillies, Britanny).  Even further back in time, another one, the 'Caledonian/Appalachian' raised enomous mountains in a line that is now broken by continental drift, but ran directly in a straight line from what is now the North Cape through Norway, Scotland, Newfoundland, to the Appalachians.  Coincidentally, this follows the same SW-NE alignment as the Alpine, but is completely unconnected.  The original mountains are long eroded out, and what is visible now is what were their deep roots, which are altered and deformed by the immense heat and pressure they experienced.  No limestones or chalk up there!

 

Limestones and chalks are organic in origin, limestone being the mineral deposit of thick beds of marine animal mollusc shells that have been fused together under pressure.  Chalk is similarly formed, but less ancient and structured, and composed mainly of the shell remains of plankton and other very small animals, but in unimaginably vast quantities.

 

Check out a Great Britain geological map, plenty online.  You are looking for Carboniferous Limestone, Jurrassic/Triassic Limestone (the Wolds), and Cretaceous Chalk (the Downs, Salisbury Plain, and the Chilterns), all quite easily identified and located.  Carboniferous Limestone around the edges of the coalfields, Wolds in a line SW-NE from Dorset to Yorkshire, Chalk similarly SW-NE from St Catherine's Head on the Isle of Wight to the Chilterns and spreading out over Salisbury plain into Wiltshire and over Goring Gap into the Chilterns, then into Hampshire and splitting in Sussex and the southern part of Surrey into the North and South Downs enveloping the Weald of Kent and East Sussex.

 

Cardiff's water is supplied from the sandstones of the Brecon Beacons reservoirs, and is 'soft', though it is piped through beds of Carboniferous Limestone to the north of Merthyr and again north of Cardif.  People who buy Calgon here are wasting their money...  The lime, calcite, in calcareous rocks is dissolved as rain water soaks through it, especially if the rain is even slightly acidic (which it very commonly has been, the more so the further north and east you go because of the direction of the prevailing winds, since the beginning of the industrialised period), and 'hardens' the water.  It settles out as fur deposits in domestic kettles and equipment, and in water pipes as well, and this settling out is the reason for the drip drip formation of stalagtites (hang down) and stalagmites (stick up) in limestone caves.

 

Steam locomotive water was taken from local supplies; Swindon was chosen as the engine changeover point on the early GW and sheds and the works established there because the groundwater there is soft despite the proximitiy of the chalk downs a few miles to the south and the Cotswolds to the northwest.  There is very little soft water avaialble anywhere between London and Bristol.  Or Leeds and Carlisle.  Or Leeds and Manchester.  Or Derby and Manchester.  Or London and the South Coast.  Or Bristol and Sheffield.

 

Hence the stains dribbling from the safety valves and the water softening plants.  Limescale is a big problem for steam locos, as it builds up as settled out deposits on the outside of the boiler tubes, hindering the transfer of heat from the hot gasses in the tubes to the water in the boiler and resulting in poor steaming.  Cleaning it off the tubes is labour-intensive and physically onerous work.  It can also affect the tender tank, feed pipes to the injectors, and the injectors themselves, which little 'stards need little provocation to give trouble at the best of times.  I don't need to tell you what could happen if they compromise the operation of the safety valves, but scale is the usual reason for them not seating properly and continually wasting steam, which is at least 'fail safe'.

 

As locos move about a bit, that being the basic idea of having them in the first place, sheds in soft water areas will have to deal with scale brought in from elsewhere as well, a constant maintenance battle.  Water tanks and columns are affected as well, so if your engine takes hard water on it's travels, it will bring it back home and the tank and columns' pipes and valves are prone to furring up.  The only locos that 'got away' with this were those use exclusively in soft water areas; a South Devon branch line like Moretonhampstead or Ashburton for example, or the Far North, Kyle of Lochalsh, or Fort William routes, some GE routes, and much of the Cambrian (though Welshpool is close to Limestone). 

 

It is no coincidence that, a mere few hundred thousand years after 'neanderthals developed tools', the traditional major industrial areas of the UK were located close to Carboniferous Limestone outcrops.  The beds are overlaid by the coal-bearing strata of all but the Kent coalfield (which is surrounded by chalk), and as the rock is resistant to erosion (it is eroded from beneath by dissolution), the resulting topography led to industries already being established in these areas even before steam power became widely used because of the fast running water that could power waterwheels for forge blowers and factory machinery.  And it is these areas that inevitably saw the greatest traffic levels on railways and hence the greatest conentrations of locos and sheds to look after them in the later 19th and most of the 20th century.  Limescale staining became more noticeable in the 'death steam' period, though, as standards of external presentation and maintenance in general were allowed to slip and the steam locos cascaded to less strenuous low speed work where poor steaming was less of an issue.  From about 1963, most steam sheds threw in the towel and just kept a few locos in good nick for such strenous work as remained to them; most sheds were short staffed and struggled even to do this.  Nobody had the manpower to worry about lime staining, it was all most of them could to keep these neglected bags of nails running at all!

 

Sorry, that turned into a bit of a 5th form geology essay ramble, sometimes I feel the obsessive need to explain completely and have to reign myself in, but you did ask!  We have covered hundreds of millions of years of the history of rocks dating back billions of years in some cases, and forces of unimaginable power (the Alpine orogenis caused the catastrophic earthquake in Turkey and Syria this week, a miniscule part of it's overall and continuing movement so far), but all absolutely neccessary in my view to your understanding of limescale deposits.

 

'It all started  with a big bang'.

[rogerzilla]

Generally, south of an imaginary line connecting the mouths of the Tees and Exe.

 

Today's Swindon mains water is classed as "medium"; it scales up a kettle fairly slowly but it certainly leaves stains.  it's a blend of water from the River Ray and some pumped from Farmoor reservoir in Oxfordshire.  The villages just  to the south often have their own supply, that can be very hard.

 

Railway companies often treated the water, either in the lineside tanks/troughs or directly in locomotive tenders.  The SR used TIA treatment borrowed from the French.

 

Boilers are not like kettles, where you pour out the water and put fresh stuff in.  In a boiler, only pure distilled water leaves in the form of steam.  The concentration of salts would therefore build up very rapidly as topping up from the tender puts yet more dissolved salts in but no salts ever come out in the steam.  To keep the concentration tolerable between washouts, there are continuous and manual blowdown valves to bleed off boiler water (as opposed to steam).  The continuous blowdown often goes into the ashpan where it won't cause slippery rails or wet passengers.

[65179]

The map towards the bottom of this webpage gives a handy rough map of uk water hardness:

 

https://www.aquacure.co.uk/knowledge-base/uk-hard-water-map/

 

There are more detailed ones elsewhere online.

 

Simon

[doilum]

As always: find a photo an individual locomotive and copy the stains.

It will be as accurate as the day it was taken.

[Aire Head]

2 hours ago, The Johnster said:

Yorkshire Dales

 

2 hours ago, rogerzilla said:

Generally, south of an imaginary line connecting the mouths of the Tees and Exe.

 

 

Not quite I live on the edge of the Dales in an area that is definitely not Hard Water because the need for Soft Water was a primary driver of the local Industry.

[melmerby]

For soft and hard also read Acid & Alkaline. The rate of acidity or alkalinity is measured on the 'pH' scale form 0 -14 with 7 being neutral

0 is very acid and 14 is very alkaline.

Alkaline water can leave a coating on whatever it is in.

Acidic water can dissolve whatever it is in.

 

Birmingham water which used to come solely from mid Wales was very soft. Birmingham also had lots of lead piping (like many other places).

The very soft, therefore very acidic water, used to dissolve lead from the pipes, which the body then ingests. Result lead poisoning☹️

 

These days according to water regulations the pH should be maintained between 6.5 & 9.5

Edited February 10, 2023 by melmerby

[JimC]

I suppose one should add that problems of water supply, quality and cost were a major preoccupation to the railways. From my readings of GWR minutes the cost of water supplies was always discussed, and water supply contracts etc were a significant preoccupation at director level in the GWR. Improving water quality was also a priority, because better water meant better boiler life and had a very great influence on running costs. In his book Ken Cook records how Swindon made big improvements in boiler life through both selection of supply and installation of water softening plants. 

[Wickham Green too]

13 hours ago, doilum said:

As always: find a photo ... It will be as accurate as the day it was taken.

Unless it's been Photoshopped !

[PhilH]

12 hours ago, melmerby said:

 

The very soft, therefore very acidic water, used to dissolve lead from the pipes, which the body then ingests. Result lead poisoning☹️

We used phosphoric acid to dose water in areas of high lead pipe concentration. This forms an insoluble layer of lead phosphate on the inside of the pipes to stop the lead leaching out. The need for it was determined by random sampling of customers taps, some areas deemed at higher risk than others.. This, combined with sodium hypochlorite to kill bugs, dosed instead of chlorine gas, formed the mild disinfectant known as tap water.

 

The upside was that thanks to my employment I always had bleach and a lifetime supply of soldering flux…..

Edited February 11, 2023 by PhilH

[Reorte]

I'd have though reservoir supplies would be generally soft; you need to consider where it's coming from too (e.g. on the map above I'm either in medium to hard or hard to very hard but it's actually fairly soft water, since it's from reservoirs and not boreholes). On the same map Manchester seems to be in a medium to hard area but that water's also fairly soft, being supplies by the Lake District and Pennine reservoirs in the Dark Peak (so again not limestone).

 

I guess for the railways this means that what sort of water a particular location had to deal with might've varied over time as the supply system evolved so fewer and fewer would've got their water from small local supplies. Or I might be dead wrong about that, if they remained independent of the large water supplies.

[Wickham Green too]

3 hours ago, Reorte said:

I'd have thought reservoir supplies would be generally soft; ...

There are reservoirs an' reservoirs ..... if you're talking large valley reservoirs that are filled from the surrounding catchment, alone, you're probably right - but smaller ones may well be used as buffer stores for water from any source. [ Look at the reservoirs round Heathrow f'rinstance - a tiny fraction of the water will be direct rainfall but the vast majority is pumped from the Thames or boreholes. ]

[Reorte]

6 minutes ago, Wickham Green too said:

There are reservoirs an' reservoirs ..... if you're talking large valley reservoirs that are filled from the surrounding catchment, alone, you're probably right - but smaller ones may well be used as buffer stores for water from any source. [ Look at the reservoirs round Heathrow f'rinstance - a tiny fraction of the water will be direct rainfall but the vast majority is pumped from the Thames or boreholes. ]

Good point, that sort of local storage reservoir is really a very different thing from the impounding reservoirs there to gather water in the first place.

[The Stationmaster]

23 hours ago, Reorte said:

I'd have though reservoir supplies would be generally soft; you need to consider where it's coming from too (e.g. on the map above I'm either in medium to hard or hard to very hard but it's actually fairly soft water, since it's from reservoirs and not boreholes). On the same map Manchester seems to be in a medium to hard area but that water's also fairly soft, being supplies by the Lake District and Pennine reservoirs in the Dark Peak (so again not limestone).

 

I guess for the railways this means that what sort of water a particular location had to deal with might've varied over time as the supply system evolved so fewer and fewer would've got their water from small local supplies. Or I might be dead wrong about that, if they remained independent of the large water supplies.

It depends where the reservoir is and, as already noited, what it is.  I know of one loco depot on the Western which got its water supply from its own collection reservoir,  In that case a spring and  streams were so i understand, involved.

[The Johnster]

On 12/02/2023 at 12:42, Reorte said:

I'd have though reservoir supplies would be generally soft;

 

If they were, nobody would have furred up kettles or pipes and Calgon would be out of business.

[The Stationmaster]

21 hours ago, The Johnster said:

 

If they were, nobody would have furred up kettles or pipes and Calgon would be out of business.

And we wouldn't be buying salt for our water softener!

[PhilH]

On 13/02/2023 at 12:26, The Stationmaster said:

It depends where the reservoir is and, as already noited, what it is.  I know of one loco depot on the Western which got its water supply from its own collection reservoir,  In that case a spring and  streams were so i understand, involved.

Eastleigh shed’s supply came directly from the River Itchen. The huge water tank on top of the dorms/offices became a fish tank over time apparently. The shed also had its  own softening plant.

[Reorte]

23 hours ago, The Johnster said:

 

If they were, nobody would have furred up kettles or pipes and Calgon would be out of business.

I always assumed they were used by people supplied from boreholes.

[Reorte]

On 13/02/2023 at 12:26, The Stationmaster said:

It depends where the reservoir is and, as already noited, what it is.  I know of one loco depot on the Western which got its water supply from its own collection reservoir,  In that case a spring and  streams were so i understand, involved.

 

The reservoir built to supply water to Stainmore Summit's still there. Not quite one for ghosts in the machine because the machine's gone, but an interesting reminder nevertheless.

[The Johnster]

30 minutes ago, Reorte said:

I always assumed they were used by people supplied from boreholes.

You don’t want to know how I misread that on the initial scan…