Saint Class 135 ish mph

Oddly enough there is some confirmation of the 90m.p.h. capabilities of a 9f away from the fevered world of the gricer. Some motoring journalists were testing what was for the era a fast car on the restriction free roads of the time when they encounter a train on the adjoining line. Gesticulations prompted a contest in which the car speedometer reached 90m.p.h. A blurry picture taken by one of the car passengers was good enough to show a 9f.

Not dynamometer car standards of accuracy certainly but far more reliable than accounts of what Uncle Fred did when Daniel Gooch was alive. Also free from gricerish considerations of whether the locomotive bore a copper chimney cap or not.

PH

 

And perhaps Francis Webb?

 

Don't you know a copper cap chimney is worth an extra 20MPH, amatuer!

 

Given the qualities of calibration of car speedometers in the past; and the fact that the loco may have been slowly gaining or losing ground on the car, it's still not much better than saying "a 9F once went at a speed somewhere between about 80 and 100mph" - scarcely more convincing than saying "a Saint once went very quickly on test".

Tom

 

Mr Churchwards definition of a damned good locomotive was two tons pull at 60 miles per hour if my memory is still working.
20kN at 27m per second is 540 kW or 733 hp at tender drawbar.
A Collet Hall with big superheater was measured to give 1430 as absolute max in cylinders.
Let us asume that a Saint could have delivered 1000 horsepower onto the rails at 60 to 70 miles per hour and less at higher higher .
A 60 meter long Danish IC3 train (Way smoother to air than a Saint)needs 1600 horsepower to go 180 kmh
A Saint has same frontal area and is 20 meter long so lets say it will need 1000 horsepower to go 180 kmh or 111 mph.
In this speed region it had less than 1000 horsepower.
120 mph is next to impossible

 

Gricers are the absolute epitome of the amateur

PH

 

Deleted

 

At least 2 tons at 70mph?

 

Well it was a long time ago but I think it was an Alvis which probably would have a Jaeger (high grade) instrument. More accurate than Uncle Fred's guestimate I would think but I did say it would not be of dynamometer accuracy. I seem to recall that the train and car ran together for some distance (Yes, vague I know)

PH

 

Think the humour in my OP might have gone over your head somewhat, In any case, I don't recall giving much credit to this story myself anywhere ?.

 

OK 850 drawbar horsepower.

 

Accuracy of speedometers (or lack thereof) aside, I note that the 9F (for which unexpectedly high speed running on both the Eastern & Western regions is moderately well attested) has approx 50% more grate area than a 29. Mr Churchward had his beasties fed the finest Welsh steam coal, whilst Mr Riddles' creations were designed to burn pretty much any old rubbish. Quite how this translates into effective production of steam when comparing the two utterly dissimilar boiler designs is beyond my ken.

It seems to me that given we are comparing a freight plodder, pulling a fairly substantial load, with a clearly passenger train oriented design hauling a tender, the disparity in power between the two designs is of less consequence than the steam production rate. Could a Swindon No.1 boiler have generated enough to sustain a speed of 120mph (let alone 135mph) for any appreciable distance? Do any of our number have the relevant knowledge to come to a convincing conclusion?

Given GJCs well known extensive testing in the earliest years of last century, I'm prepared to believe the steam circuit would likely have been adequate (given sufficient steam!!) for a short burst over the 'ton', but with any appreciable trailing load? That's another matter entirely.

So far as air resistance is concerned, I guess the Gresley & Stanier tests in the 1930s would provide the most relevant data. Any comment I could make would be as near to guesswork as makes no odds, so I won't make any!!!

 

I'm interested that no one's commented on the inconsistency between the alleged high speed jinks in 1906 or thereabouts, and the post Salisbury clampdown on high speeds which, amongst other things, led to some delay in publicising City of Truro's claimed 100mph run.

On the circumstantial evidence, I'm inclined to believe something very fast happened, but quite what we'll never know. Yet the tension between the conduct that Sunday and more general policy of the day is nagging at me.

 

Anyone ever NOT given a company vehicle full throttle?!

Despite being a Gwr fan I'm still having trouble with that 120 figure, and as for 135mph but if we were talking about a streamlined duchess instead...

 

Too many posts and not enough time to answer them.

I am a diesel engine designer - and I'll say what Piston Speed means to me:

- Wear. Higher piston speeds mean more in-cylinder wear. And yes, if a Saint was to do sustained >100 mph running every day it might have problems. But a few minutes won't be an issue. (In the same way that an F1 engine might run at 25 m/s for a few hours whereas our engines are 9-11 m/s for >10,000 hours)
- Separation of Con Rod Big End. As the piston goes over TDC it wants to escape through the Cyl Head - and the Con Rod Bolts are the only thing stopping it. However on a Double Acting steam engine the big end needs to cope with thrusts in both directions and so are much more robust (am I right in thinking that Saints had a solid big end?)
- Breathing. High piston speeds may be the reason you go from 2 valves to 4 valves or even more. In Steam Engines the equivalent thing is the rate at which IHP reduces with speed for a given steam rate. It has been said that the original Saints with inside steam pipes had an advantage - as the steam chest volume was much larger and so there was minimal loss of pressure while the valves were open. Also the original blastpipe was larger than that on the Halls in the 1950s when they were tested.

BTW a NYC J3a Hudson (29" stroke) was run up to 700 rpm on greased rails (=164 mph for that loco). I guess if that had happened at Swindon we would be told we dreamt it....

 

Two runs by Saints in their original condition - without superheat - suggest much more power than that....

2930 - Saint Vincent
70 mph on level track with 485 tons tare

2915 - Saint Bartholomew
90 mph with 320 tons - near Ruislip

 

Car speedos are deliberately set to over-read to allow for tyre wear. They are not permitted to under-read. 10% used to be the norm although my Focus is pleasingly only about 5% over on new tyres. For much the same reasons , I wouldn't have any faith in the Avis speedo reading.

 

I fear you rather miss the point(s) I was making. Firstly, a speedometer was likely to be less fallible than an individual's (gu)estimate. Specifically I said it would not be to dynamometer car standards. Secondly it was an an indication, away from the sometimes over-excitable enthusiasts sources of these machines ability to run really fast.

Incidentally Avis are a car hire company. Alvis were the makers of high end sporting cars.

PH