As for the high speed wheel spin....thats pretty dangerous!
here is an extract from what happened to 'Blue Peter' (an A2) near Durham in 1994
In 1994, during the first run of a preserved steam locomotive from Edinburgh to Newcastle, 60532 suffered extensive damage during a catastrophic uncontrolled wheelslip.
During an unscheduled stop at Durham station the inexperienced footplate crew overfilled the boiler. As the train departed south across Durham viaduct an initial slip was poorly controlled by the driver, who then reopened the regulator too early, probably worried about stalling on the bank up to Relly Mill. The force of the initial slip caused the boiler to prime, carrying water over into the regulator valve and jamming it open. This allowed passage of steam through to the cylinders, perpetuating the slip and accelerating the driving wheels. When the driver attempted to wind the reversing gear back into mid-position to halt the slip, the force of the boiler spun it into full-forward position, and the driving wheels reached a rotational speed of 140mph before the cylinder heads blew off and the motion disintegrated.
The driver suffered major injury to his arms, as a result of the screw reversing lever whipping around when he released it. The accident brought to light the importance of traincrews being trained on the specific locomotives they were driving, rather than simply a common general instruction on steam locomotives. Neither the driver or fireman had ever worked 60532 before, and were unaware of the locomotive's sensitivity to priming, which led to the accident.
And some of the sound and vision footage
http://www.steamsoundsarchive.com/13/audio/19940814.mp3 - In this file, you can hear the real extent to which the drive wheels continue with themselves, and the discharge from the cylinders as the heads are blown off.
http://www.youtube.com/watch?v=YjsNbzg1UaI&fmt=18 - This film shows how bad the damage is, as the wheels started to grind away at the metal with such force, even sparks were sent off
Anyone working on the footplate of a steam locomotive is either fully trained or under training supervision, especially when working a steam special on the national rail network, so these are not novices by any means. They are also usually accompanied by an experienced locomotive operations inspector to ensure all procedures are strictly adhered to and advice on the route given.
The crew may have been inexperienced at working this class of loco, but on all steam locomotives they are equipped with water gauges that as a fireman/woman you regularly check to ensure the correct boiler water level for the prevailing conditions are maintained. No way should the priming described have taken place.
As for the driver allowing the engine into a violent slip, that was pure incompetence, as he should have immediately have closed the regulator, as has to be frequently done on ex-Southern, later BR, Bullied 'light' Pacific's as they are very prone to light footiness and can slip at the slightest provocation! Once the slip passed the point of recovery, at the latest, the cylinder drain cocks should have been fully opened to release cylinder pressure.
My conclusion is that the footplate staff were trained, but were incompetent and the driver probably decided to 'play to the crowds' (as I know some drivers do!) and lifted the regulator too fully and too fast, thus ending up having to fight the steam pressure forcing the regulator to stay open. As you stated Mark, the motion was rotated to destruction at speeds up to 140 mph, with cylinders wrecked, and even a driving wheel turned out of position on its axle!
It took tremendous forces to attain that, and the steam railway preservation movement hopes it never happens again!
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Topic: TOP GEAR (Read 3749 times)