Castle Aching

[Compound2632]

8 hours ago, wagonman said:

When City of Truro did a guest stint on the NNR not so long ago it coped perfectly well with their standard 4-5 coach trains even up the bank to Holt.

 

... those presumably being BR Mk 1 carriages, with rather lower rolling resistance than carriages of the turn of the century. And not aiming for an average speed in the high 50s!

[wagonman]

2 hours ago, Compound2632 said:

 

... those presumably being BR Mk 1 carriages, with rather lower rolling resistance than carriages of the turn of the century. And not aiming for an average speed in the high 50s!

 

Average speed in the low 20s...

[Metropolitan H]

11 hours ago, wagonman said:

 

What you say is undoubtedly true but remember that the trains – especially the Mail specials – were comparative feather weights too. I don't have figures to be able to compile comparable power:weight ratios though I suspect not a vast difference then and now.

 

When City of Truro did a guest stint on the NNR not so long ago it coped perfectly well with their standard 4-5 coach trains even up the bank to Holt.

But the 3440 "City of Truro", that we know today is a very different locomotive to that which was credited with the high speed "Ocean Mails" special bu Rous-Marten. At the time of the high speed run "CoT" was a Saturated steam loco fitted with slide valve cylinders - it wasn't rebuilt to its current Superheated condition till 1911 and it was 1915 before it gained replacement piston valve cylinders - both of which modifications added to the loco's power and free running.

 

But were the City class (10 locos) as good when introduced - "CoT" was built 1903 - and was it effectively being tested at the time of the record run?

 

I don't know the answers, but am still a fan of the loco I saw out and about - on the Didcot, Newbury and Southampton line amongst others - in the late 1950s / early 60s.

 

Regards

Chris H

[Edwardian]

Interesting.  I have the City of Bath (I think!) in 1906 livery.  Based on the info and photographs to hand, I reckoned that it was not possible to get the Bachmann model back before 1911-2 without major surgery: Link.  

 

Even so, the reinforced plating round the hornblocks might need taking back, which would be fairly drastic.  In short, Bachmann's CoT isn't really representative of anything save that loco in preserved condition.  

 

 

In those days, nobody cared much about such a restrictive tooling.  These days, despite the costs of extra tooling slides, manufacturers seem to have acknowledged the need to make more of an effort. 

 

 

I don't like Mondays ....

 

 

[Hroth]

I've the Bachmann Ambulance Train pack, with the Midland coach set and City of Birbegum in a RODdish livery with Great Western on the tender (Hey, I got it when the prices hit rock bottom before starting to creep back up again).  Unfit for much in the way of ordinary use but I might buy the Oxford Railgun and it can appear on my Minories layout (when I get around to laying the platform lines) as a WW1 diorama, with the nurses from the set shaking collecting boxes.....

[Hroth]

15 hours ago, Compound2632 said:

 

Unlikely - that 80 mph is a flying average from pass to pass of the two stations, not from a standing start to a stop. Without access to the log, I think we can assume the speed was pretty much steadily in the 77 mph - 83 mph range. I would imagine that he (she/it) had settled down to a steady rate of steaming and was eating up the miles without too much need for adjustment of regulator or cut-off - the driver had found a sweet spot and let her run there. Not like thrashing a North Western 2-4-0.

I'm not disputing that DoC wasn't hitting 80 when she passed Shrivenham. However, not having a gradient profile, or a list of PW slacks and Station/Junction mandatory speed limits, its difficult to be dogmatic, but I'd be surprised if DoC could keep a steady speed over the whole distance.  Yes, Brunel engineered the route to be as "level" as possible, but to pass through 26 or so stations and about 8 major junctions at a constant 80mph would be a bit far fetched and for every mph under the average, she would have to run at the same rate over the average to regain time, or faster to compensate for a greater speed differential. Then she also had to pass through the Chilterns (modest gradients) to gain the Thames valley too.

 

No doubt there was a bit of risk-taking with allowed speeds, but to contemplate maintaining the average with sppeds in the range of 77-83 mph is a bit wishful, and why I'd suggest that maxima may well have been around the 90s

[Nearholmer]

I’m a bit of a terror for tech details about these things, but setting all that aside, a big single tearing along a racing stretch must have been a magnificent sight and sound.

[Edwardian]

24 minutes ago, Nearholmer said:

I’m a bit of a terror for tech details about these things, but setting all that aside, a big single tearing along a racing stretch must have been a magnificent sight and sound.

 

25 seconds on an A4 followed by 3 minutes of No.1 at speed in 1938: 

 

 

[woodenhead]

10 minutes ago, Edwardian said:

 

25 seconds on an A4 followed by 3 minutes of No.1 at speed in 1938: 

 

 

It doesn't sound like I expected it to 

[Annie]

For some reason I couldn't get any sound at all on that video clip.  Great piece of film though.

[Annie]

An interesting photo archive with mostly period photographs with excellent details that would be useful to any pre-grouping modeller.  There are some photos of modern error vandalism, but fortunately they are few in number and can be safely ignored.

 

http://www.kentphotoarchive.com/kpa/search/index.php?pagenumber=1&townkeywordname=&featurekeywordname=RAILWAY

 

(I naughtily stole the link from another thread)

[Nearholmer]

Some superb images. I especially like the one of Bexhill West.

 

i did have a minor complaint about Kent attempting to annex bits of Sussex and Surrey, then I found this http://www.kentphotoarchive.com/kpa/search/thumblarge.php?townkeywordname=&featurekeywordname=RAILWAY&startnumber=254&pagenumber=13

[Edwardian]

23 minutes ago, Nearholmer said:

Some superb images. I especially like the one of Bexhill West.

 

i did have a minor complaint about Kent attempting to annex bits of Sussex and Surrey, then I found this http://www.kentphotoarchive.com/kpa/search/thumblarge.php?townkeywordname=&featurekeywordname=RAILWAY&startnumber=254&pagenumber=13

 

The north face of Knowl Hill?

[Compound2632]

19 hours ago, Metropolitan H said:

But the 3440 "City of Truro", that we know today is a very different locomotive to that which was credited with the high speed "Ocean Mails" special bu Rous-Marten. At the time of the high speed run "CoT" was a Saturated steam loco fitted with slide valve cylinders - it wasn't rebuilt to its current Superheated condition till 1911 and it was 1915 before it gained replacement piston valve cylinders - both of which modifications added to the loco's power and free running.

 

But were the City class (10 locos) as good when introduced - "CoT" was built 1903 - and was it effectively being tested at the time of the record run?

 

Now that is interesting - apologies but I had to go and check against other sources, as I'd always understood that piston valves were a prerequisite for superheated steam, as, so I thought, slide valves depend on the lubrication from wet steam. Equally, I was surprised that such a "modern" and forward-looking design would not have had piston valves from new. S.W. Johnson (no apologies for citing him again) first used piston valves on the 115 Class singles of 1896 and they were noticeably freer-running than even the previous singles, with Charles Rous-Marten getting 90 mph with one on a down express from St Pancras - apparently with a following wind but nevertheless the highest speed recorded with a service train in the 19th century. (Tying with one of T.W. Wosdell's compound J Class singles a few years earlier, but in that case the record was set during a series of staged tests.)

 

7 hours ago, Hroth said:

I'm not disputing that DoC wasn't hitting 80 when she passed Shrivenham. However, not having a gradient profile, or a list of PW slacks and Station/Junction mandatory speed limits, its difficult to be dogmatic, but I'd be surprised if DoC could keep a steady speed over the whole distance.  Yes, Brunel engineered the route to be as "level" as possible, but to pass through 26 or so stations and about 8 major junctions at a constant 80mph would be a bit far fetched and for every mph under the average, she would have to run at the same rate over the average to regain time, or faster to compensate for a greater speed differential. Then she also had to pass through the Chilterns (modest gradients) to gain the Thames valley too.

 

No doubt there was a bit of risk-taking with allowed speeds, but to contemplate maintaining the average with sppeds in the range of 77-83 mph is a bit wishful, and why I'd suggest that maxima may well have been around the 90s

 

Rous-Marten was on board; in referring to this run in one of his Railway Magazine articles he explicitly states "the maxium speed was not nearly so high as I have recorded on a different part of the same line on other occasions" and "And yet no record maximum was obtained". As O.S. Nock reports it (I assume he had access to Rous-Marten's log?) , the highest speed was the 82.9 mph average over 17.8 miles from Twyford to West Drayton; I'm sure he would have mentioned any singular maximum. To be running fast enough at Twyford to be averaging over 80 mph from thence to West Drayton, the train must have rattled through Reading at fair old lick - it was perhaps with such running in mind that the 1898 rebuild of the station put the up main platform on a loop! Nock states that the 34.7 miles from Reading to Westbourne Park were run at an average of 80.5 mph:

 

Twyford - West Drayton 17.8 miles at 82.9 mph = 12 min 53 sec

Reading - Westbourne Park 34.7 miles at 80.5 mph = 25 min 52 sec

 

That leaves 12 min 59 sec for the 5 miles from Reading to Twyford and the 11.9 miles from West Drayton to Westbourne Park. Since the long-distance high average is quoted to Westbourne Park one must assume that there was no significant slowing before that point but the brakes were applied (and how) shortly (very shortly!) afterwards. So the average speed over the Reading - Westbourne Park sections outside the Twyford - West Drayton section was 78.1 mph. The speed through Reading must therefore have been over 70 mph, probably no lower than 73 mph.

 

So there may have been a little easing through Reading! A permanent way slack is mentioned, with the clear implication that it was outside the Shrivenham - Westbourne Park section. Otherwise I doubt at the time there was much in the way of formal speed restrictions - I suspect thinking in such terms is anachronistic. 

 

EDIT: Hroth, re-reading your post, I'm afraid I've noticed that you need to look at your atlas. Shrivenham is east of Swindon, in the Vale of the White Horse. Gently downhill all the way, mostly wide flat valley except threading through the Goring Gap. 

 

EDIT: For comparison, the non-stop run from Paddington to Plymouth with the Royal Train on 14 July 1903, with No. 3443 City of Bath. Slough was passed at 72.2 mph, the average speed through Reading (i.e. the average speed over the 7.64 miles from Twyford to Tilehurst) was 70.7 mph, including a maximum of 76.3 mph near Sonning, and Didcot was passed at 75 mph. I think that's evidence for not much in the way of speed restrictions in the Thames valley, considering the nature of the train! There was a slowing to 15 mph through Bath, and even slower over the Bristol avoiding line. The Bath slack shows up as an average speed of 59.5 mph over the 6.73 miles from Bathampton to Saltford.

Edited May 13, 2019 by Compound2632

[RedGemAlchemist]

4 hours ago, Edwardian said:

 

25 seconds on an A4 followed by 3 minutes of No.1 at speed in 1938: 

 

 

Spectacular. You never think of such an antiquated-seeming design being able to move at those sort of speeds, but seeing it in action is a marvel.

[Compound2632]

4 minutes ago, RedGemAlchemist said:

Spectacular. You never think of such an antiquated-seeming design being able to move at those sort of speeds, but seeing it in action is a marvel.

 

Ah, but now you need to take away the frenetic oscillation of the outside connecting rod and imagine yourself standing on the platform at Reading as Duke of Connaught glides by at 70 mph+ without any visible sign of effort. 

[Martin S-C]

James - what a simply spectacular piece of film. That film of the Stirling single caused me to wonder if we can estimate the speeds.

 

From 2:00 to 2:14 (14 seconds) the driving wheels revolve 30 times.

 

From 2:20 to 2:28 (8 seconds) they revolve 36 times (!).

 

From 2:45 to 2:56 (11 seconds) they revolve 51 times (!!).

 

These timings are crude - I counted the revolutions of the con rod against a digital stopwatch, then ran the video again and checked against the timings watermarked on the video. I'm probably not spot-on but close.

I am no great mathematician (nor even a lesser one) but given the driving wheel diameter can we calculate speed here?

[wagonman]

34 minutes ago, Martin S-C said:

James - what a simply spectacular piece of film. That film of the Stirling single caused me to wonder if we can estimate the speeds.

 

From 2:00 to 2:14 (14 seconds) the driving wheels revolve 30 times.

 

From 2:20 to 2:28 (8 seconds) they revolve 36 times (!).

 

From 2:45 to 2:56 (11 seconds) they revolve 51 times (!!).

 

These timings are crude - I counted the revolutions of the con rod against a digital stopwatch, then ran the video again and checked against the timings watermarked on the video. I'm probably not spot-on but close.

I am no great mathematician (nor even a lesser one) but given the driving wheel diameter can we calculate speed here?

 

I wouldn't like to guarantee the film speed which seems a bit variable: there is a pedestrian 'walking' in the foreground as one point – and he's definitely 16fps in a 24pfs world!  Edit: he enters at 1:00 min

Edited May 13, 2019 by wagonman
add timing

[Compound2632]

Nevertheless 30 revolutions in 14 seconds would give about 30 mph; 51 revolutions in 11 seconds, 65 mph.

 

That's also assuming its not slipping!

Edited May 13, 2019 by Compound2632

[Edwardian]

I wondered about the pedestrian. Though jerky, I'm not so sure he was going unprototypically fast for a chap with a camera hurrying to see a train!

 

Slower, but with sound!

 

 

 

[Donw]

We are talking about a steam enginethe power dpends on the firing and driving. The cut off may have been left alone but the fire would not be constant  At some point the fireman would have built up the fire ready for the run  but is will not give of its best straight away. In fact  the fire may be at its hottest just before it needs more coal added. Plus the fact that the harder the loco works the stronger the fire is drawn.  So it cannot be considered constant during the run. If the boiler pressure has dropped a little on the climb to Whiteball then with a light load the pressure may actually be rising on the downhill run. 

Also the gradient may not be constant there may be slight changes not sufficient to put a gradient post but just enouh to give the engine a bit less or a bit more help.

 

For me I believe that COT did touch the magic ton. This was a special downhill run with alight train not an everyday turn. Generally the Cities appear to have been fast locos with a suitable train.

 

Don

[Donw]

HAving seen King James I coming through the centre road at Reading at a very fast rate on the Down Bristolian the memory of that has stayed with me. No idea of the actual speed but I reckon 10mph faster than normal. Quite a sight.

 

Don

[Annie]

2 hours ago, Edwardian said:

I wondered about the pedestrian. Though jerky, I'm not so sure he was going unprototypically fast for a chap with a camera hurrying to see a train!

 

Slower, but with sound!

 

 

 

The beautiful way the locomotives seems to glide along the rails is very much a visual delight.

[EKR]

As a boy I saw both engines double heading an excursion at Oxford.

Clearly remembered from my close association with choking to death by leaning over the footbridge (Hinksey) as they departed.

[runs as required]

What a wonderful piece of film

it made me realise how little I know about the single wheelers. I assume the Stirling singles pre-date the later Spinners and DoC fitted with steam sanders, though No 1 must have had them retrofitted in its C20 years.

As it gets away from the station there was not a visual sign of a slip ( astonishing when you think of the minuscule steel to steel area imparting the acceleration). So the steam around the front end would be ... what ? Steam escaping from the piston seals ?

i noticed the safety valve permanently feathering - and was actually blowing off at the end while stopping at Rothley.   What a wonderful memory for the young lad doing the firing - did he get his fingers burnt right at the end? The driver turned the glass off with his handkerchief !

 

[it reminds me I must check on what happened to my pre-ordering at Shildon a couple of years back. I still exist on the fragments of my Kitmaster bought at Hattons on Smithdown Rd in 1959 and assembled as respite from the drudgery of student working drawings]

dh