Was the GWR really so conservative?

[DavidB-AU]

GWR had electrification plans for Devon and Cornwall in the 1930s but the Depression and the war got in the way. The first section earmarked for wires was Exeter to Plymouth due to the South Devon Banks. They had already been working with Brown Boveri on the gas turbine (originally due to be delivered in 1940) so it's possible they could have adopted the Swiss overhead 15kV AC 16 2/3 Hz. One of the drivers was a sizeable chunk of the coal traffic beyond Exeter was for their own locos.

 

Cheers

David

[Joseph_Pestell]

7 hours ago, DavidB-AU said:

GWR had electrification plans for Devon and Cornwall in the 1930s but the Depression and the war got in the way. The first section earmarked for wires was Exeter to Plymouth due to the South Devon Banks. They had already been working with Brown Boveri on the gas turbine (originally due to be delivered in 1940) so it's possible they could have adopted the Swiss overhead 15kV AC 16 2/3 Hz. One of the drivers was a sizeable chunk of the coal traffic beyond Exeter was for their own locos.

 

Cheers

David

 

Interesting idea for a "might-have-been" layout. Love the thought of those Swiss design locos of the era at the head of GW chocolate and cream coaches. Would existing Swiss designs fit within the GW loading gauge? If so, it's probably an HO project.

 

I posed this question some weeks ago after seeing the excellent Totnes layout. Would there have been much coal traffic at all over  the South Devon Banks? It would seem more sensible for coal to be taken by ship to Plymouth and various other Cornish ports. Slow moving minerals trains would be a real headache to fit in around the passenger service even if that was rather less frequent back then.

[JimC]

2 hours ago, Joseph_Pestell said:

 

Interesting idea for a "might-have-been" layout. Love the thought of those Swiss design locos of the era at the head of GW chocolate and cream coaches. Would existing Swiss designs fit within the GW loading gauge?

Isn't there a commercial model of Kerosene Castle being planned? That would be an obvious donor body shell for such a scheme.

[The Stationmaster]

7 hours ago, Joseph_Pestell said:

 

Interesting idea for a "might-have-been" layout. Love the thought of those Swiss design locos of the era at the head of GW chocolate and cream coaches. Would existing Swiss designs fit within the GW loading gauge? If so, it's probably an HO project.

 

I posed this question some weeks ago after seeing the excellent Totnes layout. Would there have been much coal traffic at all over  the South Devon Banks? It would seem more sensible for coal to be taken by ship to Plymouth and various other Cornish ports. Slow moving minerals trains would be a real headache to fit in around the passenger service even if that was rather less frequent back then.

Apart from local coal (and no doubt some domestic coal) a lot of coal moved into the West of England by sea - for example coal for Torquay gas works was transhipped to rail at Kingswear for the final bit of its journey.  Coal waas also landed at Plymouth.

[DavidB-AU]

15 hours ago, Joseph_Pestell said:

Interesting idea for a "might-have-been" layout. Love the thought of those Swiss design locos of the era at the head of GW chocolate and cream coaches. Would existing Swiss designs fit within the GW loading gauge? If so, it's probably an HO project.

 

If the war hadn't got in the way and the wires were commissioned in the early 1940s, you'd probably be looking at something at least mechanically similar to the Ae 4/6 for passenger trains and Ae 4/7 for goods. Not off the shelf as they were 9'10" wide.

 

Cheers

David

[runs as required]

5 minutes ago, DavidB-AU said:

If the war hadn't got in the way and the wires were commissioned in the early 1940s, you'd probably be looking at something at least mechanically similar to the Ae 4/6 for passenger trains and Ae 4/7 for goods. Not off the shelf as they were 9'10" wide.

Would the wires have been stormproof along Dawlish - Teignmouth or would Exeter - Newton Abbot have been inland?

dh

[DavidB-AU]

I was almost going to include that in the post at the top of the page. GWR didn't consider this to be an issue as portions of the US Atlantic coast already been electrified for almost 30 years by then.

 

Cheers

David

[MidlandRed]

Although it's actually WR rather than GW, there's some fascinating stats in the RCTS History of the 9Fs which show average works dwell times in working days across the fleet which indicate Swindon took over 2.5 times longer than Crewe to carry out an HI or HC repair on a 9F (requiring 115 rather than 40 days) - Gorton required 50 - there is also the saga of  Stanier 8Fs being allocated to the WR owing to objection to new 9Fs after the initial batch 92000-7 - but the only ones acceptable would be those which had been built at Swindon, resulting in complicated cascades being required - WR did end up with 92203-92250 though!

 

Although this is strictly not GW one gets the impression that the WR continued their traditions - perhaps there is reason for all this in that if Swindon's manufacturing tolerances were that much better, perhaps that could justify these points - rather than it just appearing a profligate and parochial way of going about things? Regrettably the 9F stats don't reflect longer periods between repairs on WR than other regions so an argument that longer works periods represent a more thorough overhaul, and thus less unscheduled attention required in between doesn't seem to follow. 

Perhaps this reflects a conservative attitude to engineering? I guess you'd have to look at the GW v say LMS or LNER/SR fleet stats to draw pre nationalisation conclusions - interesting that there should be such a divergence of approach though. 

Edited November 20, 2019 by MidlandRed

[DCB]

1 hour ago, MidlandRed said:

Although it's actually WR rather than GW, there's some fascinating stats in the RCTS History of the 9Fs which show average works dwell times in working days across the fleet which indicate Swindon took over 2.5 times longer than Crewe to carry out an HI or HC repair on a 9F (requiring 115 rather than 40 days) - Gorton required 50 - 

Makes you wonder if they had a pool of spare boilers for the (Non) standard 9Fs. in the way they did for GW classes. Even the 9 47XX had a pool of ten boilers.  Actually its a shame they didn't use 47XX cylinders and regulator valve, and maybe lower superheat  to avoid the excessive cylinder wear at high speeds which mitigated against 9Fs being used on the passenger duties they were otherwise eminently suitable for.  GW King type safety valves would have been a useful improvement over the Ross Pop type, and  t save reinventing the wheel they could have used King boilers, after all they made 34 new ones after construction of the first 9Fs

Edited November 20, 2019 by DavidCBroad

[brack]

By the 30s swiss manufacturers had built quite a few metre gauge electric locos for home and export, so I imagine there would be little problem designing something to fit the uk loading gauge for gwr needs.

[LMS2968]

5 hours ago, DavidCBroad said:

Makes you wonder if they had a pool of spare boilers for the (Non) standard 9Fs. in the way they did for GW classes. Even the 9 47XX had a pool of ten boilers.  Actually its a shame they didn't use 47XX cylinders and regulator valve, and maybe lower superheat  to avoid the excessive cylinder wear at high speeds which mitigated against 9Fs being used on the passenger duties they were otherwise eminently suitable for.  GW King type safety valves would have been a useful improvement over the Ross Pop type, and  t save reinventing the wheel they could have used King boilers, after all they made 34 new ones after construction of the first 9Fs

The 9Fs were not suitable for express passenger work. Yes, some were timed at 90 mph, but at that speed the piston speed and rpm were very excessive, which would if made common practice have resulted in mechanical damage to the engine and also to the track. Imbalances within the system, both rotational and reciprocating, rise with the square of rpm, so at 90 would be four times higher than at 45. They rode like a coach so the enginemen would not realise just what was happening below their feet or the damage being caused.

 

And by the way, fitting GWR cylinders with 30 inch stroke instead on the 9Fs' 28 inch would have made things worse.

[jim.snowdon]

10 hours ago, LMS2968 said:

The 9Fs were not suitable for express passenger work. Yes, some were timed at 90 mph, but at that speed the piston speed and rpm were very excessive, which would if made common practice have resulted in mechanical damage to the engine and also to the track. Imbalances within the system, both rotational and reciprocating, rise with the square of rpm, so at 90 would be four times higher than at 45. They rode like a coach so the enginemen would not realise just what was happening below their feet or the damage being caused.

 

And by the way, fitting GWR cylinders with 30 inch stroke instead on the 9Fs' 28 inch would have made things worse.

Is there actually any evidence that the exploits of 9Fs at high speeds actually caused them any damage?

 

Jim

[LMS2968]

Probably not, but their supersonic exploits were very limited before authority stepped in and barred them from such passenger work. But the potential was there.

[jim.snowdon]

Exactly, but then that was the same "authority" that then came with an idea that locomotives should be subject to a speed limit based on their driving wheel diameter, and then had to be told that that would mean limiting the speed of their main line pacifics and making the timetable unworkable. Knee jerk reactions by management are not a reliable indicator of an actual problem.

 

Jim

[TheSignalEngineer]

On 15/11/2019 at 13:20, Miss Prism said:

There was an excellent article (in Backtrack?) some years ago about the possible electrification (primarily 1500V d.c. overhead) of various bits of the WR as part of the '1955 modernisation plan'.

 

It was too ambitious and far too expensive.

 

In the late 1960s I had pass across my desk a BRB investment programme document that suggested Swansea to York electrification should follow on from completion of WCML through Glasgow and ECML London to Edinburgh. At that time there was a large amount of coal and steel industry related traffic on the NE-SW axis.

[LMS2968]

1 hour ago, jim.snowdon said:

Exactly, but then that was the same "authority" that then came with an idea that locomotives should be subject to a speed limit based on their driving wheel diameter, and then had to be told that that would mean limiting the speed of their main line pacifics and making the timetable unworkable. Knee jerk reactions by management are not a reliable indicator of an actual problem.

 

Jim

Wheel diameter isn't the only issue, there's balance v hammerblow as well.

 

Express engines tended to be multi-cylinder. In part this was to obtain the power output but it allowed individual cylinders to be of smaller diameter and each to produce less power individually. In turn, this allowed lighter drive components so less reciprocating mass per cylinder. But multi-cylinders tend to provide a certain amount of balancing one against the others, allowing reduced balance weights in the wheels and a reduction in hammerblow. If the cylinders are in line and all drive on to the same axle, the need for reciprocating balance disappears. But it is impossible to fully balance a two-cylinder engine; it cannot be done. If you fully balance the reciprocating masses you simply get the same forces but acting vertically, which is what hammerblow is.

 

Remember that the LMS tried an experiment with a Black Five (wheels one foot larger than the 9Fs') at a rotational speed of 102 mph and found that the driving wheels were lifting 2.4 inches off the track.

 

The dangers were very real.

[jim.snowdon]

Which is precisely why that management reaction illustrated how uninformed its authors were. We might have an appreciation of the theory, but not of the actual data relating to how a 9F would actually perform at that speed.

 

Jim

[JimC]

3 hours ago, jim.snowdon said:

Is there actually any evidence that the exploits of 9Fs at high speeds actually caused them any damage?

Its not something you'll necessarily know. Components subject to excess speed may not catastrophically fail, but will wear much faster. Its documented that the cost of overhauls was one of the biggest if not the biggest factor in total cost of ownership of steam locomotives.

[jim.snowdon]

2 hours ago, LMS2968 said:

Express engines tended to be multi-cylinder. In part this was to obtain the power output but it allowed individual cylinders to be of smaller diameter and each to produce less power individually. In turn, this allowed lighter drive components so less reciprocating mass per cylinder. But multi-cylinders tend to provide a certain amount of balancing one against the others, allowing reduced balance weights in the wheels and a reduction in hammerblow. If the cylinders are in line and all drive on to the same axle, the need for reciprocating balance disappears. But it is impossible to fully balance a two-cylinder engine; it cannot be done. If you fully balance the reciprocating masses you simply get the same forces but acting vertically, which is what hammerblow is.

 

Remember that the LMS tried an experiment with a Black Five (wheels one foot larger than the 9Fs') at a rotational speed of 102 mph and found that the driving wheels were lifting 2.4 inches off the track. 

Worth noting is that the 9Fs were balanced differently to the majority of previous locomotives, including the Black 5s, resulting in a reduced hammer blow compared to traditional practice, as well as ower unsprung weight.

 

1 hour ago, JimC said:

Its not something you'll necessarily know. Components subject to excess speed may not catastrophically fail, but will wear much faster. Its documented that the cost of overhauls was one of the biggest if not the biggest factor in total cost of ownership of steam locomotives.

My point is that it is now 67 years since the 9Fs were designed, and nearly 60-odd years since the 90mph exploits. None of us are in possession of the actual facts of the time, let alone knowledge of the design calculations, with the result that speculation is liable to be rife.

 

Jim

[Zomboid]

2 hours ago, LMS2968 said:

Express engines tended to be multi-cylinder.

Reputedly the fastest steam express locos on the world were the Milwaukee road F7s, which were 2 cylinder machines operating a schedule which required sustained 100mph+ running. They had 7 foot driving wheels though. The Pennsylvania T4s were also extremely fast and they were two 2 cylinder engines on a single frame. If anyone had measured either of them properly, Mallard would just be the British/ European record holder.

 

Which is not to say that there's no issues associated with such matters, but running 2 cylinder engines at very high speeds was safely achieved over 10 years before BR came into being, never mind the construction of the standard steam engines.

[DavidB-AU]

2 hours ago, Zomboid said:

 The Pennsylvania T4s were also extremely fast and they were two 2 cylinder engines on a single frame.

 

But worth remembering they ran on rail that was 155 lb/yd.

 

Cheers

David

[runs as required]

Am I right in recalling that the 9Fs 90mph exploits were on the WR?  

If so, is that because their 'Evening Star' Swindon tolerances were more exacting than LMR works's  'good enough mother' standards ? 

dh

[Reorte]

17 hours ago, jim.snowdon said:

Exactly, but then that was the same "authority" that then came with an idea that locomotives should be subject to a speed limit based on their driving wheel diameter, and then had to be told that that would mean limiting the speed of their main line pacifics and making the timetable unworkable. Knee jerk reactions by management are not a reliable indicator of an actual problem.

 

The pacifics would've had the years of experience showing they were OK. Bits of a 9F whizzing around at speed though, fair enough that raised eyebrows at least and a result of "slow down a bit until we've at least looked into this," (and not enough need / time before they were going to be replaced to justify looking in to it).

 

Still, would've loved to have been around to see it!

Edited November 21, 2019 by Reorte

[MidlandRed]

11 hours ago, runs as required said:

Am I right in recalling that the 9Fs 90mph exploits were on the WR?  

If so, is that because their 'Evening Star' Swindon tolerances were more exacting than LMR works's  'good enough mother' standards ? 

dh

 

No - also used on the ER, at least. There were many experiments and in service modifications to the 9Fs and along with the issue of speed of motion etc in high speed passenger use has been well documented. The WR continued to use them on passenger but on the SDJR where speeds were somewhat less onerous. However the 92220 episode came to the attention of higher authority when an unscheduled water stop occurred at Reading ...... 

Edited November 22, 2019 by MidlandRed
Corrected

[The Johnster]

I'm not sure that the WR's exploits with 9Fs ever actually achieved 90mph.  The story as I heard it at Canton in the 70s from a driver who had participated as a fireman, was that 'Evening Star' was rostered to the 'Red Dragon' for 3 days shortly after it's delivery new to the shed, and on each occasion it performed well and 'timed' the train.  The Red Dragon was the prestige service from South Wales, loco changed at Cardiff General for 10.00 am departure, Newport only stop, and a 3 hour 10 minute run time to Paddington.  Load was up to 14 bogies unassisted from Severn Tunnel to Stoke Gifford, 16 assisted.  

 

So, there was plenty of recovery time built into the WTT for the train, which was not required to run much over 80mph even past Badminton.  There were some very fast runs between there and Paddington if time had to be made up, but normally high speed was not necessary, and Evening Star ran to time and had no need to make time up.  An ideal loco for the Red Dragon between Severn Tunnel and Badminton is something that can steam well despite slogging hard at about 50mph, which sounds very much like a description of a 9F to me...  

 

Maximum speed was probably in the low 80s.

 

The ER story is different, a 9F pulled off it's booked freight working at Peterborough IIRC to replace a failed A4 on the up Flying Scotsman, the stuff of which legends are made.  The driver was told to make up as much lost time as he could, and arrived at the Cross on time, having run at over 90mph with no ill effect apparent to the loco or the track.  KX stationmaster apparently told him that he had been told to make up whatever time he could, not try to break the sound barrier...

 

9Fs could and sometimes did run very fast, and might even have been able to run faster, but this is not a sensible way to operate them.  Piston speed and stroke is what causes hammer blow, and the way to reduce hammer blow is to use large diameter driving wheels to reduce piston speed and multiple cylinders to reduce the stroke.  The point is that even if a loco can run fast despite not being designed for that purpose, it is not wise to let it do that regularly as the effect on wear, downtime, and track renewal will be palpable.

 

The job of the locomotive is to time the train while running profitably, and because operating costs increase geometrically with speed, it is not necessarily the best practice to hammer it even within the speed limits.