What Ifs, and Locos that never were.

Ahem - GNR and LBSCR first!

They'll be one of the latter running in not too many years, touch wood.

Tom

 

And they were reasonably closely related were they not?

 

No, the LBSCR design was 100% the conception and work of Brighton

Tom

 

The only Atlantics on the Southern. Also the LMS group only had the L & Y ones. For some reason, they were almost all on the LNER with the NER, NBR, GNR and GCR all having them. The GWR only had the Stars, or was it Saints? which ran briefly as 4-4-2s before being converted to 4-6-0s and the three French built De Glenh compounds

 

A recent piece I read in a magazine that was lying around commented that the basic Ivatt design made a lot more sense on the GNR than the LBSC. I think the comparison was that when the Brighton loco had reached its destination, after a few stops and some severe gradients, the GNR engine was just getting into its stride around Peterborough. I suspect the East Coast pattern of work was better suited to Atlantics than most, with relatively long runs demanding plenty of grate capacity for sustained steaming and not placing too much premium on starting.

That isn't to say that the Brighton Atlantics weren't good engines, just that maybe an engine more intrinsically suited to the job was possible.

 

At risk of boring (almost?) everyone stupid the complexities of the GW Atlantics were:

Saint (2 Cyl) 3rd prototype/pre production No 171 was built as a 4-6-0 in 1903, but soon converted to 4-4-2 to compare with La France, the first GWR deGlehn. Reconverted to 4-6-0 in 1907. 19 more Saints followed in 1905, 13 as 4-4-2s and 9 as 4-6-0s. The 4-4-2s were named after characters in Sir Walter Scott's Novels and are sometimes called Scott class. The Scotts were mostly converted to 4-6-0 in 1912, so the two wheel arrangements had a comprehensive trial.

Star (4 cylinder) prototype No 40 was built in 1906 as a 4-4-2. She had an ingenious modified Walschaerts valve gear design with no eccentrics. There are a lot of tales, some contradictory, some even approaching conspiracy theory status, about why this wasn't repeated. She was converted to 4-6-0 in 1909. No other Stars ran as 4-4-2s.

The GWR locos all used the narrow firebox No 1 boiler, and the deGlehns also had narrow boxes, indeed they tended to alternate between the original boilers and GWR Standard 1 boilers.

North Eastern and Southern 2 and 3 cylinder Atlantics had no more than about 80% of the nominal tractive effort of the GWR and deGlehn locomotives, but the much later Schools Class 4-4-0s on the Southern had a similar sort of power output to the Saints on 4 coupled wheels.

 

am I right in thinking that 103 and 104 with narrow boxes had slightly larger grate area than the Ivatt Atlantics with wide ones?

worth noting that despite 102/103/104 being bought for trials that they also had a useful service life - lasting a long time for a non standard class (and compound at that) - they must have been highly thought of

 

And the re-creation (which I have the highest regard for) will have a Great Northern boiler.

 

Of course, a slip of the finger that! I should have known ,being a pre grouping aficionado !
I also donate to the Atlantic project.
One that seems to be forgotten , which were very good performers in their day was the North Eastern Z atlantics, & impressive looking engines too.

 

Bump, and also , how exactly did that steam/diesel loco work !? And also the Paget loco?

 

The Kitson - Still hybrid loco used steam on one side of the pistons and conventional diesel injection on the other. Steam was used to provide starting torque and eliminate the need to change gear ratios. So up to 5mph the loco worked like a normal steam engine. After that the diesel injection kicked and the steam was shut off. The small boiler was oil fired to get it up to temperature. After that waste heat from the cylinders would keep the water warm. Steam could also be used as a booster when required.

At the time electric and hydraulic transmissions were still in thier infancy so this wasn't quite as crazy as it sounds.

The loco itself was underpowered and under boilerd for its size although considerably more fuel efficient than a conventional steam loco. The concept did find some favour in stationary and marine applications though.

Tim

 

A LB&SCR 4-6-0, using a enlarged H1/H2 Atlantic boiler with increased boiler pressure. Interesting idea?

 

Presumably a different firebox would have been needed to clear the rear coupled wheels?
Worth remarking tangentially just how significant Urie's three designs of 4-6-0 were in hindsight.
Quiz question - what was the second class of "modern" mixed traffic two cylinder long travel outside valve 4-6-0 in the British Isles?

 

The L class boiler would have been a bit more suitable. If the Southern had done it a few years later they might have classified it as an equivalent to the King Arthurs in a weird Eastleigh/Brighton hybrid style and called it the N15X.

Wait a minute....

 

Not really a logical development - the natural enlargement from an Atlantic is a Pacific (because the wide firebox means you still need a trailing truck). By contrast, a 4-6-0 would naturally have a narrow firebox - if you wanted an LBSCR 4-6-0, the starting point would presumably be to enlarge the B4x. That would give you something akin to an LNER B12, i.e. an inside cylinder 4-6-0. Alternatively, you could start with the class L tank engine and convert to a 4-6-0 tender engine, as was done - you get a Billinton / Maunsell N15x. Very handsome looking engines, though not stellar performers.

Tom

 

And I think then the design starts running into other complications. As the GWR demonstrated with the Great Bear, and Stanier repeated early on with his Pacifics, if you simply extend an Atlantic boiler with a longer barrel the tubes come out too long and there are steaming problems, so a good boiler for a Pacific must be fundamentally redesigned. The best (in british practice at least) all seemed to incorporate a combustion chamber.

 

Case in point - Gresley's early Pacific design for the GNR of 1913 was an enlarged Ivatt Atlantic in almost all respects. The Pacific that eventually emerged as Great Northern had some specific details carried over from the 1913 design (wheel size, spacing, cartazzi) but significantly the boiler was an all new design and maxed out to the GNR loading gauge, together with the enlarged cab and eight wheel tender developed from the standard 6 wheel tenders on the GNR.

It's said Gresley looked at the Pennsylvania K4 design for the A1 - not surprising if true given the design of the K4 (albeit, Gresley went for the round topped boiler as per GNR practice and not belpaire).

 

From memory No. 40 had what was known as the 'Scissors' valve gear in which one of the inside cylinders motion work was used to drive the other one's valve. Recollections (without looking it up) are that a patent was taken out on this idea by (I believe) Deeley of the Midland Railway so the GWR didn't progress this idea further.

 

? Are there any similarities between a K4s and an A1/A3 apart from the wheel arrangement?

 

It's more the overall design ethos rather than copying exacting aspects of design. Gresley, understandably, looked around when he was travelling in the states and the K4 was one of probably many locomotives he looked at and took inspiration from. The K4 stands out though as it was a successful Pacific and one Gresley personally invested time in and is recorded as having done so.

His first mogul, and then Pacific, followed many of the trends over in the states and abroad, maxing the boiler out to the loading gauge in particular being the biggest change. The K3 and A1 were for their wheel arrangements were some of the largest locomotives of their type when introduced in the whole of the UK (noting the Great Bear and the Raven Pacifics).