Boiler

The `laws' applying to locomotive boilers have always been somewhat sparse, Factory Acts do not apply, but the Railway Inspectorate, who control the activities of most railways, require that all boilers are properly examined and maintained, and that they have proper insurance. The all embracing Health and Safety at Work Act, 1974 imposes many liabilities and responsibilities on any employer or operator of virtually anything, and can be certain to catch anyone who does not operate and maintain a boiler properly so that an accident occurs.

The main Regulation affecting boilers and their inspection is The Pressure Systems Safety Regulations 2000. Unfortunately I do not as yet have details of these new regulations, so the following details of the older Pressure Vessels and Transportable Gas Containers Regulations, 1989 No 2169. will remain available for now but please treat these as guidelines and obtain a copy of the new regulations.
Section 4(2) states that the pressure system shall be properly designed and properly constructed from suitable material so as to prevent danger.














Section 4(5) states that the pressure system shall be provided with such protective devices as may be necessary for preventing danger, i.e. boilers must have adequate safety valves to prevent excess pressure building up. Although these regulations refer to mobile systems, this term does not include locomotives.

Section 5. Suppliers and manufacturers, also anyone modifying or repairing any boiler, shall provide written information concerning design, construction, examiniation, operation and maintenance as may reasonably be required for these regulations to be complied with. These people shall ensure that the following information is indelibly marked on the boiler or a plate attached to it: Manufacturers name, date of manufacture, standard to which vessel was built, Maximum pressure of the vessel, the design temperature.



Section 8. The user shall not operate the system unless he has a written scheme for the periodic examination by a competent person of protective devices and the pressure vessel itself., and any parts of the pipework in which a defect may give rise to danger. A competent person is one who has knowledge of the pressure system, normally the boiler inspector. This written scheme will specify the nature and frequency of examination, and will specify any special measures necessary to prepare the pressure system for safe examination other than those it would be reasonable to expect the user to take.

Section 9. Covers the preparation and submission of reports by inspectors, including specification of repairs (if any) required to be done. The Health and Safety Booklet Locomotive Boilers HS(G)29 is a revision of one in which AIR and ARPS (now merged as HRA) were involved in preparation several years ago. Its purpose is to provide guidance on the practical applications of Regulations made under the H.& S.W. Act of 1974.




This booklet gives emphasis on the importance of examination, testing, repair and maintenance of boilers being carried out to an adequate standard, which in turn requires the choice of suitable persons both to carry out and supervise these functions, and this includes keeping records of steaming times, examinations, repairs and maintenance, including washing out. For this purpose Responsible Person(s) should be properly appointed within each organisation, who should not only have knowledge of locomotive boilers, but also authority regarding their use; he must if necessary prohibit the use, even raising of steam, in any boiler if there is any doubt as to its safety.

The importance of the competent persons - boiler inspectors - having experience of locomotive type boilers is very much stressed, and the choice of insurance company may be dictated by the organisation's experience in locomotive boiler examination.






Examinations by the competent person will normally be made on completion of a new boiler, with a hydraulic test followed by a further examination the first time the boiler is steamed. Further thorough examinations should be made within 14 months, i.e. every year, with a cold examination internally and externally as far as can be made accessible, followed by an examination in steam. The competent person may also need to make similar examinations after any major repairs have been carried out on the boiler, at his discretion.

Engines working on the National Network are required to have their boilers lifted from the frames, all lagging stripped off, all tubes and superheater flues, as well as all boiler fittings, removed for thorough examination internally as well as externally every seven years. For engines working only on independant railways this may be extended to ten years; in very exceptional circumstances this may be extended further at the discretion of the competent person.

Suitably experienced staff, appointed by the responsible person, are also required to inspect boilers internally and externally before and after wash out and also before bringing into use a boiler which has been laid up for a period during the currency of the certificate.

Water is a corrosive substance in conjunction with steel, also steel, copper and water form an elemental electric cell, leading to local corrosion. The purer mountain waters are often acidic, and therefore more corrosive than the hard waters, the dissolved substances of which deposit onto the tubes and plates, leading to them overheating and burning, and which have to be removed, often by mechanical means, at wash out. To avoid these problems water needs to be treated, exactly how should be researched by a water treatment chemist, preferably not from a water treatment firm who will be wanting to sell their products.

Whilst tubes and flues can be recycled, it is better that they are worn out before they are removed when this becomes necessary.

A boiler is a very difficult thing to fully preserve; it needs to be completely dried out internally and externally, and then kept warm and dry, e.g. in a heated museum or a desert. Boilers left out of doors with water in them between use, are corroding away, and modern day usage with occasional steaming is the worst possible treatment, as continual heating up and cooling down stresses parts tending to cause fractures. Most of the boilers in use today are old, the material far beyond the age of anything that would have been in commercial service.

Boilers wear from erosion from the ash etc, as well as burning from the flames of the fire. Wet ashes in a smokebox, and water left in the bottom of a barrel or firebox can cause bad corrosion and thinning of plates. Modern welding methods of both steel and copper enable new sections of plate to be welded in, or local areas just to be built up.

In the end, the economics of major and expensive patching up of old boilers must be considered against that of building a completely new boiler, many small boilers are now being built new.

Photos from http://www.2857.org.uk/2857_28xx_news_2005.html



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