Where does the best (and worst) coal come from?

I vaguely remember some dismay when Lady Windsor closed as some people then thought it was the only coal the larger Swindon locos would steam on!

 

That rather tells it's own story. Actually road steam people thought much the same.

PH

 

Lady Windsor was very good coal, from memory it was more robust than the average Welsh, perhaps this was as a result of being from a deeper seam. It had the characteristic of swelling to several times its original size when part burnt, opening out like a large cauliflower. Too much in the back of the firebox and it could swell and almost block the fire hole opening, as others will remember. The WSR used it in the early 1980's before the mine closed, and again in the early 1990's when we had the opportunity to purchase several lorry loads of sweepings off the site when it was being redeveloped, the sweepings being washed and screened. Like Ffos-y-Fran it produced an incandescent white fire when the locomotive was working hard, perhaps even more so, a level of heat that never occurs with the Midland and Scottish long flame coals.

A note on 'washing' of coal. This is a process to remove stone which is heavier than the coal by floating the coal in a stream of water over a weir. The water has additives to increase its density, this density can be altered to suit differing coals. Washing in nothing to do with removing the dust, this is done by passing coal over vibrating screens of varying sizes. In the case of Ffos-Fran the final process the coal goes through as it is being loaded into the lorry is to pass over such a screen to remove undersize lumps.

Andy.

 

Is it likely that lump coal will continue to be available? I am told that the UK 'lump coal' market is now getting down to 250,000 tonnes pa and looks as though it may become to small for suppliers to bother with.

 

Amongst other classifications, coals can be divided into caking coals and non-caking coals. The latter are the ones that swell up and can confuse the unwary fireman. Caking coals are used in coke making, although not all caking coals are suitable for this.

Part of the Swindon brain washing. In days when coal was in plentiful supply there were many coals to rival good Welsh coal in quality, the prime considerations being ash content and fusion temperature and chlorine content. Welsh coal often suffered from too much of the latter, unlike Scottish coals, which tended to be chlorine free. In addition to attacking fireboxes, chlorine causes bird-nesting on tube ends.

 

We recently moved away from using Welsh coal; I believe that the reason was because of excessive attrition of fire bars. Certainly that issue seems to have diminished since the change. As others have said, price per ton is not necessarily a good measure of value; you have to consider the price per ton, the calorific value, and the impact on long-term maintenance costs to get a total cost for using different types of coal. The stuff we currently use is certainly smokier than the Welsh, but with the right technique that can largely be obviated; in particular firing "little and often". With the Welsh coal, I would typically start to build up a big fire at Sheffield Park about 15 minutes before departure. If you do the same with the current coal, you are likely to produce a lot of smoke and end up blowing off, because it catches much faster. A smaller fire to start with, built up much closer to departure time avoids both problems, but you then end up firing more during the journey to compensate starting with less. The place you really notice the difference is coming south. With the Welsh coal, you rarely needed to fire much beyond Kingscote on a large loco; the residual coal on the grate would have swelled up to cover the grate and would last all the way back, with just an occasional shovel to fill any developing holes, and a small round south of HK to get up the little climb from Tremaines Crossing. With the current coal, you need to ensure it doesn't completely burn away to reveal fire bars, so it is not uncommon with a thin fire to need to keep patching in small amounts almost all the way back to Sheffield Park.

One characteristic our current coal has is to produce a lot of fine ash, which tends to go through the bars into the ashpan or collect in the smokebox. For a small loco in particular doing a long duty (three or more round trips, i.e. 66, 88 or 110 miles for the day), it is advisable to come on shed and rake out the ashpan after two trips to avoid it becoming too full; the larger locos will generally go a whole day without problem. Fortunately however, the ash doesn't seem to form clinker to anything like the same degree as the Welsh coal did.

Tom

 

Lump coal generally attracts a premium price so it can be attractive to suppliers if there is a regular market. Far better for them to sell a lump of coal than grind it down to fines and get less for it if your coal prep plant has suitable screens. The danger is that environmental legislation will reduce the market for industrial coal, which is invariably fines, and if you can't sell the fines, which is the majority product of any coal winning, there will be no large coal.

 

Does anyone know what proportion of that is used by Heritage Railways? A very "finger in the air" guess I'd make is that for the 100 or so railways in the HRA, the usage is somewhere in the range 50 - 100,000 tons per year (probably at the low end of that range), but I've never seen a figure. Would be interesting to see how that figure split up between heritage railways, mainline steam, road engines, historic ships, fixed heritage attractions such as pumping stations, and other users such as domestic usage.

Tom

 

Tom,

Your observations regarding Ffos-y-Fran are correct in every respect.

The problem with fire bar damage is easily solved by using the high chrome cast iron when a grate is due to be replaced. For your use these should last 20 years, being of high chrome any clinker does not adhere to the bar and they do not corrode on the surface. Life is limited by cracking of the lower web which will finally result in the bar breaking, cracked bars can run for many years in that condition once internal stresses are relieved. In practice experience is that the lower web need not be as deep as with grey cast iron. Other points to note are that the bar does not sag or distort.

For information the material is 28% chromium.

Andy.

 

Tom,
I wonder if it is the Bluebell way to close the dampers to control the fire when the regulator is closed? It was something that I was taught when I was first starting out on the footplate and it is there in the Black Book. It was only later in life that an ex-BR driver said to me: 'If you want to avoid problems, once you open your dampers, they stay open.' When you think about it, it makes good sense. With a white hot fire at 1400C and more, the firebars and the ash are kept relatively cool by the primary air supply. If you cut off that supply, the radiant heat will soon raise the ash temperature, causing it to melt and likewise the firebars. It becomes even more critical for the firebars if you don't have a lot of ash to protect them. For that reason, it is important to keep the dampers open until the fire has cooled to a much lower temperature.

Edit:
I've no experience of high chrome firebars, as advocated by Andy but it sounds to be a good idea if firebar life is a problem.

 

I'm told that this is exactly what has recently happened in Scotland. The power stations have closed and without their demand for fine coal, coal production generally has become uneconomic.

 

No, we are always expressly warned against that, for the reasons you cite. "Once open, they stay open" 'til the end of the day. The cyclic variation of temperature is a particular issue on the Bluebell though. Given a loco on a regular multi-round trip duty, the loco will be working pretty hard for the first forty minutes or so of each cycle, and then will have relatively modest efforts or be stationary until it is ready to depart heading north again 2.5 hours after the first departure. The gradient diagram will reveal why: about 8 miles between 1 in 75 and 1 in 55 heading north but only about 0.25 miles of 1 in 60; 1.25 miles of 1 in 122 and 0.5 miles of 1 in 150 coming south, none of which is really hard enough or long enough to give a really hot fire.

Tom

 

It's one of a number of things that scare small children round steam locomotives, such as whistles and cylinder cocks blowing steam. Still I do accept the general point.

PH

 

This explains why, on a quite recent visit to Sheffield Park, 847 was smoking like b*****y at times. I recall thinking "Daw Mill lives" but now you have become involved in this thread I can be a bit more specific. On that day, much of the firing appeared to be done by a trainee, so the clag was more forgivable. However there is more to this issue than firing technique and firebar life.

Visitors to steam railways now are being treated to a sanitised version of the grim reality of the past. They were filthy then but they cannot be filthy nowadays. Some of the more perceptive posters on Tripadvisor (yes such do exist) are fully aware of this. I recall one lady who had been disappointed with the majority of steam railways but was pleased to find one where, as she put it, as much attention seemed to be paid to to cleaning the inside of the carriages as the outside of the locomotive.

Now on my recent visit the rolling stock was perfectly fine inside and out. However in the couple of years since I was last there, Sheffield Park had become noticeably more smoke stained and "gritty". I was not surprised that this fuel produced more fine ash; it was quite obvious it did. Keeping stock and buildings clean is a hard and thankless task so minimising the labour of those involved ought to be part of the equation.

Paul H

 

A GWR Castle at speed - 5043 Earl of Mount Edgcumbe racing alongside the M5
This you tube video is very impressive to me, Do not know how many members have seen it but on the subject of fire management the crew has things nailed down. First half of video, smoke is apparent ranging from a dark gray to light gray. Second half the exhaust is almost straight steam with a trace of smoke mixed in. Pressure relief valves show just a whisp of steam which means to me she has full boiler pressure. As I have read in previous comments various locomotives had distinct preferences as to type & brand of coal they were fed. This looks (to me) as a happy locomotive. Somewhere I read that the Castles (and likely other makes) were given greater superheater surface for the reason that post-war coal quality was falling. Were mines closing as early as that and good grade coal may have been mined out in the closed mines?

 

Some railways were more anti social than others. The assault on the eardrums from LNER pop valves are in a different league to the gentle hiss of the GWR.

 

After the war the best quality coal was for export only! We had huge debts to settle.

 

After the war the mines were nationalised and the NCB simply regarded coal as coal. You couldn't specify where your coal came from. You said what you wanted it for and Marketing Department supplied something suitable. Hopefully! Usually, but not always, from the nearest suitable source of supply.

 

I was taught , never shut your damper on a hot fire. I remember getting scorched through my jeans and overalls when we used Columbian coal, i think it was that. Do you remember that period Andy? I read in a book by a driver on the Western, that in the 20s they had some coal from a part of the seam that came from their usual source , &it was like ' sides of beef' about 4 or 5 foot long before broken , he says that you could fire it by picking it up and sliding it through the firehole, if you wanted too! Smelt different as well.
I sincerely hope the supply of lump coal will last for a few more years yet!