Saint Class 135 ish mph

Sorry Jimc - this is how myths start. Cook's statement means that the section ahead to Wooton Bassett was still occupied and that Brinkworth had not yet received "train out of section" from WB. Once the light engine had over run Brinkworth's section signal it would have been entering an already occupied section.

Peter James

 

On Facebook today is a comment lifted from the Lynton and Barnstable magazine about a photo which purports to show a LN at Barnstable Junc (Lord Howe) and saying this is impossible. I happened to notice in the same article mention of an MN doing 130...... I would suggest that's an exaggeration, depending of course on who was on the footplate and making the claim.

 

A Merchant doing 130 is as believable as a Saint doing a similar speed. One assumes the claimants in both cases were exaggerating a tad.

 

A couple of things puzzle me about this exploit.

The first is, as @torgormaig and others have commented on, the riding and braking capacity of a light engine at speed. Were it the case that such fast test runs were standard Swindon practice, attaching two or three bogie vehicles would have made scant difference to the speeds attainable for a large passenger engine, but made a considerable difference to both the braking and steadiness of the ride in the cab. It would seem inconceivable that in a works the size of Swindon that such vehicles couldn't be obtained when required.

The other issue is that if such fast runs were standard practice, I would have thought there would be more records - surely there would have been some kind of procedure in place to ensure clear sections, the conditions of a test etc? Arranging multiple clear sections in advance requires, as a bear minimum, considerable liaison with multiple signal boxes to plan when it should occur etc. Moreover, how many locos got tested that way - there are only 52 Sundays in a year when conditions might reasonably be expected to be quiet, and some of those would have had engineering works and other things not conducive to speed - what was the throughput of overhauls of large express locos at Swindon? How many locos needed testing that way every year? Was there enough track capacity?

As for a one-off incident: I wouldn't have too much difficulty believing a Saint could reach 100mph light engine. Beyond that it gets progressively harder to believe, not least because of the non-linear relationship of power with speed (i.e. 120mph requires considerably more than a 20% increase in power output over 100mph, for the same loco, load and conditions).

Tom

 

Quite a number of Edwardian engines had bogie / pony truck brakes - certainly the LBSCR Atlantics; I believe the Midland Compounds; S&DJR 7Fs etc. As I understand, they were removed because it was difficult to set up correct brake balance between the different axle loads on driving and carrying wheels, with the result that locking up the bogie / pony truck wheels under heavy braking became common. Ultimately, re-turning the carrying wheels and the effort of maintaining the brakes was more effort than it was worth in improved stopping power.

Tom

 

The number of first hand accounts being rubbished by people on his thread is starting to get surreal.

 

I think Tom has summed up my concerns far better than I have been able to. The whole thing just does not make sense when the full context of what is needed for high speed runs is known.

Sorry Jim but first hand accounts should be able to stand up to reasonable levels of scrutiny.

 

120 needs 75% more and 135 needs 150% more.
The all dominating air resistance grows power three with speed.

 

And the number of people wanting these accounts to be true when there's actually no corroborating records is equally surreal.

 

As in most areas of life people will believe what they want to believe and dismiss that which they do not.

For instance on a tourist line the other day I asked someone who worked on the railway whether he read this Forum. His reply was caustic saying that it consisted of only of train spotters - people who he obviously disapproved of but had forgotten that they are some of the ones who help keep his line in business.
He was totally convinced of his views and gave no opportunity to point out that I thought he was mistaken. He either had never been here and was acting on hearsay or he had just read some threads.

 

The idea these accounts being true is the surreal bit. There are practical limits to rotational speed of steam engines and, for many years, it was usual to design for a max of about 360 rpm. This didn't stop engine running faster than that but it generally brought problems and they were short stroke engines. If my simple maths is correct, at 120 mph (176 ft/s) a Saint with a 30" stroke (long by railway standards) and 80.5" drivers would have been doing a tad over 500 rpm with a max piston speed of around 68 ft/s. Mallard, got up to 528 rpm but, having 26" stroke cylinders, it only got up to a max piston speed of 60 ft/s. It's not that long ago that piston speeds in car engines started to exceed these levels, 3500ft/min (58.3 ft/s) being considered to be the practical limit for many years. Materials and lubrication are significant limiting factors in this.
No doubt some will come back with examples, such as the Pennsy 2-10-4's, that have achieved faster rotational speeds but the fact remains that these claims push the limits of credibility too far for me, especially when you are talking turn of the (20th) century.

 

Where railways meet fishing's 'you shoulda seen the one that got away'…

 

It's not it's got waves and ducks and things ;-)

 

Great thread to read.

People who want to believe will believe, especially the GWR centric, (guilty!). Others will dispute the idea which is probably fine but try not to confuse belief with some imagined call to rewrite the record books. I don't think anyone is going there.

Personally I don't see how such an event is beyond the realms of possibility as some have suggested. Surely in 1906 (?) the GWR was pretty much a law unto itself on it's own rails. These were men were on the cutting edge of steam with a freshly out-shopped high speed machine. Maybe they had some sort of licence for a high speed run and who knows what was in the water on that footplate? "She's sure is running sweet boys, let's push her a bit harder shall we?" ....Was C. B. Collett the original Stig?!

Anyone ever given a company vehicle full throttle? Did you tell the boss about it the next day? No, and you did it because you could get away with it and you did it just because you wanted to see what it could do...and the thrill. Nothing complicated or impossible about that.

No, I doubt they got to 135mph...but something went down that day.

By the by, I don't think anyone has touched on what the actual or theoretical mph upper limits a light engine saint might be capable of. Anyone care to take a stab?

 

To rise above the level of pub talk with a quasi-religious tinge, there has to be some hard fact. The latter on its own will stop much of the wild surmise which runs through this thread.

As for theoretical maxima are these to be pre or post superheat or, for those lines who incorporated his maxims, pre or post Chapelon?

PH

 

OK, there are other variables to consider, but as there are several known instances of Riddles' "Spaceships" hitting 90mph (a tad shy of Mach1!) with 5'0" dia. drivers, any number commonly accepted as "safe recommended rotational speed" is clearly a somewhat nebulous concept. Anyone care to run the numbers for an equivalent likely top speed with 6'8 1/2" drivers? My own "back of a beer mat" calculation throws up 121.5mph. Hardly a conclusive empirical study, but we're in the same ball park.

 

I think the lack of hard fact is the reason for it not being in the history books. Hence, we now deal within the realms of wild surmise (and entertainment). Through the mists of time comes to us a story you either believe or you don't.

As for the technical specs of the saint to be theoretically pushed to the limit - the engine they used on the day would be a good choice.

 

Hang on a minute, that's hardly comparable. A good fifty to sixty years locomotive, permanent way and materials engineering to contend with. The 9Fs were amongst some of the last steam locomotives built in this country and their engineering reflects this.

I am not sure the Saint class of around the turn of the 20th Century is comparable even if the circumstances are notionally the same.

 

I refer the honourable member to my opening and closing sentences!

 

Fair. Sorry!