The A1 Trust's Tornado was running a mainline excursion yesterday between King's Cross and York that was sanctioned for at least 90mph and apparently suffered a running gear malfunction. She had to be taken off the train at Peterborough. No official report has been issued but she had to be replaced with a diesel and was then pulled in tow to a nearby shop. Initial reports were that something hit the locomotive broadside but that has been refuted by a number of people who were on the trip. The latest unofficial word was a failure with the internal 3rd cylinders valve gear. Heres hoping this is a minor setback for the A1 Trust.

Here is a link to a BBC article.

http://www.bbc.com/news/uk-england-york ... e-43770175

Rob Gardner

For those not familiar with the route where this happened, the East Coast Mainline is equivalent to the US's Northeast Corridor in terms of importance. It is also a common route for steam excursions. This will be story of interest as it unfolds.

Too bad there weren't any A4's at Top Shed to rescue the train. ;-)

Rob

There was a press release by the trust on their website. What is an "inside motion" and how does it get damaged? https://www.a1steam.com/2018/04/14/the- ... er-update/

Aside from bad jokes about dance moves, "inside motion" is the rods inside the frames, main rods and valve rods. It does not clarify whether the failure was a main rod or a valve rod, but usually the main (power) rods have the most velocity and force, and likely to failure.

To add to Alex's correct description, Tornado is a 3-cylinder locomotive (much more common in the UK than the US). The middle cylinder is between the frame plates, with associated linkage "inside" the frame.

Rob

I am tempted to cite another example of inside-motion failure at high speed, Mallard. But I do not know if the two are mechanically related, and in fact I would suspect not.

I would be more inclined to suspect some component of the valve motion to the center cylinder, with the possibility of further damage before the locomotive could be stopped. One potential difficulty of a valve failure can be excessive pressure kept applied against one side of the piston or cylinder head, resulting in a bent main, popped head, or similar derangement, or perhaps a rapid 'stall' of driver rotation leading to extensive flatting or other associated damage,

I found one blurry photo showing some bits adjacent to the tracks that appeared to be part of the inside valve gear from Tornado. I’d suggest the failure was likely not the inside connecting rod as there are videos showing the engine, still in steam, with train attached, being towed away. I’d think a failure of the inside main rod would take some major work before the engine could be rolled again.

BTW- Tornado has a separate Walschart’s valve motion for the inside cylinder, unlike Mallard and her sisters which used Gresley conjugated valve gear for the inside cylinder. Gresley gear was known to occasionally cause problems at high speed as wear in the linkage caused the inside valve to over-travel.

Here is video before and immediately following the failure. Starting at about 23 seconds you can see a crew member looking over some mangled metal bits adjacent to the tracks. It’s hard to tell what the parts are; maybe the combination lever and part of the valve crosshead?

https://m.youtube.com/watch?v=00N0Y2UCu ... ontinue=40

Edit: at about 1:58, there’s a fairly clear shot of the inside valve gear, which appears mostly intact. The only major valve gear component I can’t see is the eccentric rod, so maybe that’s what failed.

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I know Mallard had a great deal of damage on her record run off Stoke Bank. She had to be cut from the train at the next station, but even after recently reading a book about it, I don't profess to understand what actually malfunctioned.

This has been posted on a Forum over here - apparently in an e-mail sent out by the Tour Operator - which gives a few more clues to what appears to have happened.....

“Tornado came to a stop just south of Sandy with a broken combination lever. Investigations have so far revealed that this was due to the middle piston valve overheating and binding in the valve chest. The root cause is not yet fully clear, but it is likely that insufficient lubrication was an issue. Investigations continue to establish the cause of failure in the lubrication system and any contributing factors.

The locomotive has run many miles since winter maintenance with no obvious issues in this area. Whilst we have been asked if the higher speed was a factor in the failure, at present we believe it not to be. It probably occured slightly earlier in the journey than if we had been running at lower speed, but it would most likely still have happened.”

Since I have never had an interest in 3 cyl locomotives (at least ones with 3 horizontal cylinders), I never thought about it much until reading this post. Is there some sort of provisions for boiler shell protection between the frames? It seems that if there was a main rod failure it could possibly punch into the boiler shell which, obviously, would make for a bad day.

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From wikipedia:

So, the big end bearing (at the crank axle) of the inside rod overheated. That probably doesn't constitute a "great deal" of damage, but you sure wouldn't want to continue a high speed run with an overheated main rod bearing, or you might indeed put a rod through the bottom of the boiler barrel.

The way I read it, the piston valve overheated and seized leaving bent and broken parts. This due to a lubrication failure. Somewhat similar to the SP&S 700 episode in the distant past.