Boiler Inspectors

When do inspectors determine whether a locomotive boiler gets an extension.

For example
A Locomotive's boiler time is good until December of a specific year. Would the inspectors come to the site where that engine is stored and maintained and declare in December Or can they come a month of too before than and declare that locomotive is good for an extension.

 

Basically, it's when you ask them. That doesn't mean to say that it is automatic; far from it. For a variety of reasons, inspections are rarely exactly 12 months apart so the mythical ten years may be up at some point during an annual 'ticket'. An inspector will usually give approval for a 12 month period so, in this case, it would take it over the ten years by however many months. It is likely that the next extension will be requested at the time of the next inspection but so many facts have to be counted in to the situation that no two are likely to be the same. Different rules for Network Rail, though.

 

Much like an MOT it would appear, only with the full overhaul expectation at some point - surprising really that such is not required of road vehicles.

 

A few questions I would like to ask (Which I think is valid) These guys work for Insurance companies don't they? Do they know the Ins/Outs of Boilers and what is required for a boiler to be passed? Do they have solid experience of Steam Engines and go through a tough training regime? Is it if a boiler passes it's PSI and Safety valves lift after the set PSI of the boiler? Sorry to sound Naive? But I for one would like to know and I am sure others would to. I hope someone can shed some light on this?
Thanks.

 

Certainly their experience in boiler maintenance and standards of safety is second to none - they are not tick box men in a suit and hi-vis sent by the Insurance company with no prior understanding.

 

I'm a bit unsure exactly what you're asking, but here goes.

Many, but by no means all, Boiler inspectors are employed by insurance companies. They are not naive enough to employ untrained and inexperienced people to do this work. Insurance companies generally limit inspection of riveted loco boilers to a select few inspectors because of the knowledge and experience required. There are quite a few independent inspectors out there. The choice of inspector is the responsibility of the loco owner/operator who has to ensure that the person is competent to undertake the work required. Although riveted boilers have been essentially superseded, there are still several thousand of them around on such things as locos and traction engines so it is far from being a minority subject.

Giving a boiler a 'pass' entails far more than simply checking that the safety valves lift at the required pressure. This is probably the easiest part of the whole job. A typical inspection will entail taking many plate thickness readings in the firebox and elsewhere, an internal inspection through all accessible openings using mirrors, fibre optic cameras and anything else suitable for the job. All stays will be hammer tested. Touch can play an important part in the inspection, as do the shadows cast from a light source. The main steam pipes will be examined. Fittings will be inspected, especially the safety valves and water gauges. All washout plugs and mudholes, fusible plugs, etc will also receive attention. The pressure gauge will be checked, unless separately calibrated. If all is OK, the boiler can then be steamed in the presence of the inspector who will check for any leaks or other problems. He will witness the operation of the safety valves and ensure that there is no accumulation of pressure. He will witness the operation of the injectors and check that the gauge glasses function correctly.

I've probably left out a host of things that he might do but that is the general gist of an annual inspection. MPI and dye penetrant flaw detection is often used to check for surface flaws. Welds may also be tested ultrasonically and even by radiography. Ultrasonics thickness meters have largely taken over nowadays, but in days gone by, he would often require a test hole to be drilled in platework to ascertain the thickness or possibility of grooving. (Obviously such holes would then be plugged!) Hydraulic testing also forms an important part of the testing regime but is usually only done every 7-10 years or after significant repairs.