Why no A9s ?

[drmditch]

Here is a nice (and hopefully non-controversial) question.
The classification A9 does not appear to have been used by the LNER.

The A8s were the Stamer/Darlington rebuild of the ex-NER 4-4-4 H2 class. (I think that Sir Nigel would have made the final approval for the work, but the rebuild is very much in the Darlington tradition.)

The A10s were the temporary(?) re-classification of the original Gresley A1s pending rebuilding to A3.

So, why was A9 never used?

Is there somewhere a lost proposal for a 'super high-speed' tank engine?

[Hatfield Shed]

...The A10s were the temporary(?) re-classification of the original Gresley A1s pending rebuilding to A3...

No question mark need follow 'temporary'. All the existing A1 pacifics were altered to A1/1 or A3, and the A10 designation became redundant.

Why the absence of an A9? I rather feel that those that might have been able to give an authoritative explanation have long departed this life, so unless someone digs out meeting minutes, a memorandum or similar, that explains...

[Pebbles]

I seem to recall that the A4 development with the 275lb boiler was likely to have been called A9.

[Atlantic 3279]

Alternatively, was it simply an example of the practice of leaving a gap between tank engine classifications and tender engine classifications? I know that did not apply in all cases by any means, and there was by the time the A8 class appeared no gap between A4 and A5, although neither A3 nor A4 existed when the original classifications were devised.

[Hatfield Shed]

I seem to recall that the A4 development with the 275lb boiler was likely to have been called A9.

Contra, by the time the A10 designation was used, that project was dead.

Wild speculation, might we have seen a significantly rebuilt A5 as the prototype of ET's new passenger tank, which could have taken the A9 designation if it proved successful enough to go into production?

[majormagna]

I think the reason there were never any A9s is that, when the A1s were reclassified, it was easier to simply add the 0 to the bufferbeam and documentation than to change the 1 to a 9.

[S.A.C. Martin]

Wild speculation, might we have seen a significantly rebuilt A5 as the prototype of ET's new passenger tank, which could have taken the A9 designation if it proved successful enough to go into production?

What is this speculation based on?

A 2-6-4T had been in the Doncaster drawing office in various forms for decades. The Thompson L1 was clearly a development of this line of thinking.

I really do not understand the speculative stuff around ET sometimes.

[S.A.C. Martin]

I think the reason there were never any A9s is that, when the A1s were reclassified, it was easier to simply add the 0 to the bufferbeam and documentation than to change the 1 to a 9.

A1 became A10 as Thompson intended to leave A1 open for the new Pacifics. Great Northern became A1 and then A1/1 when the Peppercorn A1s were introduced. All the Thompson 6ft 2in Pacifics were variously described as "A2" on their introductions, and the /1, /2, /3 came into existence at varying points until the Peppercorn A2 came into existence.

[S.A.C. Martin]

Is there somewhere a lost proposal for a 'super high-speed' tank engine?

Short answer: no. I say this based on the board minutes, the locomotive committee minutes and the vast archive at Kew for the LNER. The classifications tended to be given when the designs were finalised, or a prototype in building. Example: Thompson "B" class became "B1" later on but was always originally designated as type "B".