Various A4 questions

[DonkeyBalls]

Hello,

First post - please be kind!

I have always liked the A4s - particularly in lined Brunswick Green.

Some questions.

Regarding the tender - were the wheels 4'2" in diameter or 4'3"?

This source: https://www.lner.info/locos/A/a4.php suggests 4'2" whereas Slaters only produce 4'3" wheels.

Also were the tender wheels spoked (10 spoke?) or disc?
UPDATE: I've since found a couple of pictures on Flickr which support the disc wheels.

Regarding 60022 'Mallard', I know that it had a double chimney from new (first of the class to do so) but did it always have a corridor tender and was the tender streamlined or not?

Regarding 60012 'Commonwealth of Australia', I can't find any info as to whether it had a double chimney (or not) and if so from what date and also if it had a corridor tender (or not).

Finally, some pictures of the A4s have trad plates above the pistons at the fornt of the locomotive. On the "Sliver" locos (2509 Link, 2510 Quicksilver, 2511 King and 2512 Fox) these appear to be polished stainless steel. Were they always polished stainless steel on the A4s up until withdrawal in the 1960's. Pictures of 'Mallard' in 1959-61 for example seem to indicate that these were black (on those photographs where they can be seen). Was this painted or just 'end of steam' grime??

Thanks in anticipation,

DB

[Hatfield Shed]

The tender wheels were 4'2" diameter over the tyres when new, but with wear in traffic and reprofiling on a lathe would eventually be reduced to 4' diameter. Once in this state the tyre would be cut off, and a new tyre fitted to bring the wheelset up to 'as new' diameter.

My suggestion (unless going dead scale such as S4 or S7) then go for scale for 4' tyre diameter, because this typically results in the over scale flange depth placing the flange tip close to true scale position for 'as new'; and the overall wheel diameter looks right.

On the painted footplating question, our little gang were too busy yelling STREAK! to observe these beauties' painting detail in their final couple of years working out of KX...

[jwealleans]

Corridor tenders were reserved for locomotives working the non stop services and swapped around between locos as they went to Works or were transferred to other sheds. These articles will give you chapter and verse on what tender went with what loco and when.

[kimballthurlow]

Only 4 locomotives were built with double chimneys, including Mallard.
Mallard was equipped with a Non Corridor tender when first in service, but subsequently ran with the 1928 Streamline Corridor.
From the table kindly linked by Jonathon in the post above, Mallard received this tender in March 1948 by which time the tender was likely lettered BRITISH RAILWAYS and the cabside number would be 22 or E22. The tender was also modified in some of the fairing to allow for use in other regions for the Locomotive Exchanges of 1948.

Commonwealth of Australia had a streamlined corridor tender from new.
It was never changed.
The double chimney was fitted to this locomotive on 28 July 1958.
Gresley planned for the double chimney to be fitted to all 35 in 1939 but the war delayed that modification.

Source of the above material was "Locomotives in Detail Gresley A4 Class" by David Clarke, Ian Allan Publishing 2005.
Kimball

[Art Dent]

That's very interesting regarding the swapping of tenders and the sources for 'what went where & when'.

The OP asked about the tread plates - whether they were polished s/steel or painted black as most photos (where they can be glimpsed) seem to be?

It makes sense if the 'Silver Jubilee' locos had polished s/steel tread plates - after all, they had polished s/steel (or chrome?) cabside numbers and raised lettering on the tenders.

Did the rest of the 'ordinary' fleet have these too - I suspect not.

The difficulty is that most shots of the locos are taken from around lamp-bracket height meaning that the tread plates are barely visible. There don't seem to be many pictures taken from a higher vantage point so that these can be clearly seen.

Art

[Seagull]

The tread plates over the cylinders were normally painted the same colour as the adjacent part of the locomotive. So dark grey on the silver locos, black on the green and garter blue and in BR days black.

I'm not sure what material was used but it was probably either a cast steel plate or less likely a flat plate with the strips welded on. If it appeared to be polished it would be most likely from the paint being worn off in service.

Mallard had a non-corridor tender from new which it retained until March 1948. While behind Mallard the original tender was not fitted with stainless steel cut out letters. It was exchanged for a corridor tender with the rear plate cut down either side of the corridor connection to allow it to use water columns on other regions during the interchange trials.

Alan

[kimballthurlow]

... the tread plates are barely visible. There don't seem to be many pictures taken from a higher vantage point so that these can be clearly seen.

Art

In the above quoted book by Clarke, there are some good photographs from a distance of the tread plate in discussion.
And there is one photo on page 86 taken purely for the purpose of detailing this part of the engine.
Their purpose is to create foot-hold for the engine and shed men and do not appear to be particularly tidy.

So this tread plate is formed of strips at an angle across the running plate.
These 1 1/2 inch (0.5 mm in OO scale) steel or black iron strips appear to have been simply riveted (3/4 inch?) into the running plate.
They look as though they are made in a blacksmiths shop (probably as a task for apprentices) and no two are the same length, width, or thickness.
They are secured on a forward angle of 60° from boiler to edge of running plate.
At the edge of the running plate some strips are angle finished and some are cut at 90° (with some protrusions).
It is quite probable that these strips wore away and were replaced as required.
Hence the variety of shapes and sizes.

Kimball

[kimballthurlow]

Corridor tenders were reserved for locomotives working the non stop services and swapped around between locos as they went to Works or were transferred to other sheds. These articles will give you chapter and verse on what tender went with what loco and when.

Thank you Jonathon for the link, that is a very useful guide.

Kimball

[Hatfield Shed]

There don't seem to be many pictures taken from a higher vantage point so that these can be clearly seen...

On the rear of the dust jacket of the 'LNER Reflections' collection (ed. N Harris, pub. Silver Link ISBN 0-947971-03-3) drawn from the Hulton Picture Company's stock: a view from front and above in bright sunshine of the newly completed 2509 in Doncaster works yard is the best I am aware of. The finish is extremely crisp, no hint of 'apprentice work' in adding those tread grips. Of course what happened during the ensuing 30 years or thereabouts in service might have somewhat altered things...

Plenty of interest inside too, including a group of pictures of A4's in course of erection, which emphasises the hand built nature of the streamlined casing.

[DonkeyBalls]

Thank you all for the responses to my questions.

I have a question for Hatfield Shed from his above post.

You say that the dustjacket of 'LNER Reflections' has an overhead shot of the treadplates but no mention as to whether they are shiny and polished or painted in 'loco black'.

Can you help please?

Meanwhile, I will try to track down at least a picture of the cover of that book.

Thanks also to kimballthurlow for the info on 'Locomotives in Detail' book by Clark.

I have now sourced a copy for reference.

DB

[Art Dent]

The book 'Mallard and the A4 Class' by David McIntosh also has some pictures (mainly b&w) that may help.

ISBN 978 0 7110 3297 2, Ian Allen Publishing

Art