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

Hello Dick,

Most, if not all, the footage of 611 seems to be on non-stop excursions rather than purely railfan outings and I suppose the footplate staff are unwilling to take chances with steam production when hauling 1000 tons up 2% grades complete with sharp reverse curves. It is a mighty beast which does its work in utter mechanical silence.

Don't U.S. trains have to give "2 long, 1 short and 1 long" whistles for each grade crossing?

PH

 

Absolutely correct. Only problem is that blowing off is considered as antisocial as black smoke.

 

Not by me.

PH

 

As a railway manager, it's one of my pet hates. Along with leaving electric lights and heaters switched on unnecessarily and for the same reason!

 

It would be better if you merely made your point rather than indulged in quasi sarcasm. Neither are good but it is far less harmful to discharge water vapour into the atmosphere than unburned carbon particles.

PH

 

First bar of Handel's "Dead March" from "Saul" (or so I was told!)

 

Depends on whether you are paying fitters and machinists to remove, overhaul and refit safety valves that have been worn out by excessive blowing off!

 

Sounds as if it could be.

 

Or paying them to remedy other problems resulting from handling errors such as bearing failure caused by lack of lubrication. The point was whether black smoke or blowing off steam were held to be equally anti-social. I held black smoke to be worse.

PH

 

What an excellent thread.

Coal is not a processed fuel like gas or petrol and will vary greatly from mine to mine, seam to seam, and within a seam. Because of this referring to a coal by its source is far from reliable, for example Ffos-y-Fran open cast site works 22 seams of varying thickness, not all of which are suitable for locomotive use so only 4 find their way to heritage railways. At least Ffos-y-Fran coal comes direct from mine to user, many coals come from distribution points and can be a mix of nearly anything. Russian for example could be sourced from any number of mines and seams, as a result one load can be very different to another.

Nearly all coals will have the capacity to produce heat and boil water in a locomotive, some are better than others but unfortunately none are perfect. Which will be chosen by a user will depend upon a variety of factors that are important to todays users.

Availability. Midland hard coals will suit some users but if no company is mining that fuel it is not an option. The remaining significant mines exist to supply the power generation and steel industries, the heritage market and garage forecourt are just an extra fraction of a percent of their production.

Size. Industrial users have equipment that is designed to use pulverised fuel, many producers pulverise the coal at the mine to make handling easier. Locomotives rely upon sized coal such as Doubles, Trebles, or Cobbles, sizes that may not be available.

Friability. A measure of how easily the coal crumbles to smaller sizes. Soft coals such as Welsh are easily damaged in handling and roughly treated will reduce to dust. Hard coals such as the old Daw Mill could withstand mechanical loading with little degradation. Firemen will prefer not to have a tender full of dust and only a few lumps amongst it.

Volatility. This is a measure of the percentage of gaseous elements within the coal. The higher the volatility the lower will be the fixed carbons, a high volatile coal may be 40% gaseous and a low volatile coal 15% gaseous, much below 15% and the coal is unsuitable for locomotive use. The gaseous elements will be given off very quickly when the coal is heated within the fire and if insufficient oxygen is available will pass up the chimney unburnt and wasted, smoke at the chimney is an indication of wasted fuel. The non-volatile fixed carbons take longer to burn so a low volatile fuel is less smoky. Firemen have to learn to use the two types of coal quite differently, little and often with the high volatiles, the low volatiles can be fired quite heavily as it is slow to come up to full heat production, 15 minutes in some cases, because of this the fireman must anticipate steam demand as putting on fresh coal will initially cool the fire.

Ash and clinker. All coals will produce ash, but the ash produced will melt to clinker in differing ways. Provided ash can be kept below the ash fusion temperature clinker is less of a problem. General rules being to always keep dampers open when the fire is hot and never use fire irons to stir up the fire, if the fire burns normally and is comparatively thin the ash is generally at the bottom on the fire bars where the primary air through the ash pan keeps it cool. Fire irons will bring it up into the bulk of the fire where it becomes hot enough to melt and later solidify on the bars. This is a generalisation and coals will vary.

Calorific value. Not normally an issue for our locomotives, the lower the value the more coal that will be required for the same steam output.

Sulphur and chlorine. Impurities that are best avoided as their potential for generating corrosion on the fireside of the boiler is serious.

Price. It matters little how much the coal costs per Tonne, what is far more important is how far £100 worth of coal will move the train. To measure this it is important to record locomotive consumption and locomotive work done. WSR experience over the years has indicated that Welsh coal has always been cheaper in use despite often being more per Tonne. The greatest effect on cost per mile is fireman training by a long way.

Fire bars. There is no doubt that fire bars can be easily damaged depending upon the coal and the heat of the fire. Some railways do experience problems with short fire bar life, the WSR was also afflicted. About 15 years ago the WSR undertook an experiment on a locomotive which was fitted with a BR rocking grate. Fire bars were made out of a variety of materials; grey cast iron, SG iron, mild steel, chrome cast iron, stainless steel. These bars were fitted across the grate in a repeating pattern and the locomotive returned to service, the location of each type of bar being recorded. After a period of time it became apparent that the mild steel was the least suitable and the chrome cast iron by far the most successful. 9351 and all subsequent home locomotives being so fitted as bars required replacement. Although a chrome cast iron is about twice the price the life is considerable, those in 9351 lasting 97,000 miles with only about 10 being changed.

Sorry for this being long winded and please excuse any typos.

An important subject as coal may become the greatest threat to the continuation of locomotives in the future.

Andy.

 

Both are anti-social pollutants as far as neighbours are concerned. Black smoke may be a chemical pollutant but blowing off is very much a noise pollutant. Black smoke should never be there but you have a bit of a defence with blowing off if the guard doesn't blow the whistle when it's time for departure. Excess whistle blowing and idling diesels also fall into the noise pollution nuisance category.

 

That's pretty much about it.

 

Great post Andy!

There was a danger this thread was turning into the armchair enthusiast society; its good to get proper technical discussion on this forum!

 

Sorry Paul but you don't live in Alresford.

With your eye for economy I would have thought that the considerable wasteage produced by blowing off would be one of your pet hates. It is one of mine but when I'm teaching and someone has overdone it then I'll tell them that they can blow off anywhere but in stations and see how they get on controlling the boiler from there.

The Welsh is difficult to control when it's got really hot and then you need it to calm down, keeping the brick arch white for quite a while. This "lag" is primarily why I prefer the harder Scottish coal and practice restraint when getting an engine ready for the climb. It can be a mammoth task trying to instil this confidence into a cleaner who is anxious and has a bit of "spare time" before the off.

This is, indeed, an excellent thread and just proves that it is horses for courses as far as coal is concerned. I don't like the Welsh stuff on my standard gauge railway but at the narrow gauge it was superb.

 

Agreed - many thanks Andy for taking the time to type all that up.

Regards,

Dan

 

Yes, at least in my Grandfather's day. There is always the exception depending what a given operator decides to put into the whistle cord.
I would love to see what Southern #611 would do to Lickey or Shap. Cant forget Union Pacific #844 or Southern Pacific #4449 but I suppose their tonnage would be prohibitive on those lines where bridges would be encountered plus I do not think they would fit thru tunnels or overpasses.

 

Of course; the people who wish to complain - frequently! Commiserations. I would rather have steam than smoke over my washing but there we are.

Paul H

 

Britain paid a high price for being first in the field in terms of restricted structure dimensions. However we fell seriously behind in aspects such as application of roller bearings to rodding as well as axleboxes. Compared to the routes in Virginia over which 611 pulls 20+ heavy vehicles, Shap is near "Water Level" and gently curved whilst Lickey, although a touch steeper, is dead straight.

Paul H

 

Every heritage railway has to look at the cost first. SVR is using Northumbrian at the moment. Despite the odd rock/ stone its reliable stuff. Not very smokey either. When we trialed welsh it was a balance between cost and the affect it had on firebars with the higher chlorine content. Many SVR fireman of the 80s will remember Lady Windsor coal from Wales which I have never heard a bad word. Calverton coal always used to be good.