498 Class Wheel Details

[JimG]

I'm about to start on a 498 Class Pug in S scale and I'm two weeks into the (up to) six week wait for drawings from the NRM. I would like to make a start on the wheels and I've done the drawings for them except for one feature. Were the wheel bosses flush with the prominent balance weights or did they protrude above the weights by a small amount? I have only two pictures to go by at the moment - one in Jim MacIntosh's Livery book (also in MacLeod's book) and one in a Wiki online, but both pictures don't give me sufficient detail to provide an answer one way or the other. I know that the GA drawing will probably have a section through the wheels which will give the answer, but that could be four weeks off.

I am intending to mill the spokes, weights and boss as one piece so it would be handy to get it correct before starting to cut six of them.

Jim G.

[MIKEWILLIAMS]

This is an enlargement from a St. Rollox glass plate of number 534

Best

Mike

[JimG]

Mike,

That is an excellent shot for my purposes - looks they are flush. Many thanks.

Jim.

[Dave Lochrie]

Jim,
I think Mike's picture is pretty conclusive, but here is a pre-group shot from a low angle (Dawsholm/ Maryhill area I think) of CR No 510, and 2 later close-ups, LMS 16153 and BR 56154 (ex CR Nos 527 & 528), just to confirm nothing changed.

CR No 510 .jpg (128.33 KiB) Viewed 22972 times

498 wheels.jpg (84.73 KiB) Viewed 22972 times

Dave L

[JimG]

David,

Many thanks for these pictures which back up Mike's evidence.

I do like the picture of the Caledonian era locomotive. That's some embellishment on the smokebox door for a small shunting locomotive. I get the feeling that it might have been more appropriate on an express passenger locomotive. Also, on the same picture, is that more embellishment under the buffer beam, just behind the coupling link - the ring with some shape inside it?

Jim.

[JimG]

First go at a wheel centre - not quite there yet.

498Wheel06.jpg (56.36 KiB) Viewed 22937 times

534 wheel.jpg (16.18 KiB) Viewed 22937 times

I'll use a larger radius at the flare between spoke and boss, and thin down the boss and weight. I will also thin the spokes slightly. This is my first try, making assumptions in 2D CAD - empirical modelling.

Jim G.

[JimG]

Things have moved on a wee bit with the wheel situation. I had a discussion with Jim Mac about drawings in the archive and I think he suggested looking at the Campbell-Cornwell drawings. There are not many covering the 498 class, but there was one for the driving wheels. So with Jim's help, I got that drawing (and one for the cylinders) from the Uni's archive service, and received them just a few days ago.

One notable feature of the drawing was a very definite groove between the boss and the weight - the question I had raised at the start of this thread. I had also got a picture of 498 in Caledonian days (also via Jim Mac) and the groove was present. Here's a small extract from the picture of the rear driver...

Cal498Wheel - 498.jpg (11.6 KiB) Viewed 22833 times

However, on inspecting the other pictures I have, which are all Pickersgill era locomotives, there is no groove - as in the pictures early on in this thread. So it looks as though a different wheel pattern was used for the later orders, and the spoke shaping looks slightly different as well, although I'm not so convinced of that.

I've also noticed that some other castings are different - like the front cylinder covers. I wonder if some, if not all, of the original patterns were destroyed and had to be re-made for the Pickersgill orders. I also wonder why MacIntosh only built two, when there seemed to be a need for another twenty-one locomotives a few years later. And their longevity would imply that they were a successful design.

Jim.

[emckeng]

Is it a groove or a shadow? It may be the latter if the balance weight sits proud of the wheel rim as it appears to do. If there is a double line shown on the drawing it may indicate a chamfer on the edge of the balance weight which might have been necessary for casting purposes. All speculation of course.

regards,

Ed. McKenna

[JimG]

Ed,

Here's a small section from the wheel drawing across the balance weight - there is quite definitely a groove between the boss and the weight.

Cal498WheelSection.jpg (70.55 KiB) Viewed 22825 times

If you look at the picture in Mike Williams' message near the start of the thread, you will see that the boss and weight are one surface with no obvious join or level difference. But the picture of 498 does show a groove between the boss perimeter and the weight.

Jim.

[emckeng]

Yup! That's definitely a groove. I'll stick to what I know in future.

Ed. McKenna

[jim mac]

Among the St Rollox collection at the NRM which is currently being catalogued as a CRA project is the following; one of a series of posed shots in LMS livery assumed to have been taken shortly after grouping.

16151 wheels (SRX 203 AM30 008).jpg (54.22 KiB) Viewed 22810 times

jim mac

[JimG]

Jim,

That is an excellent picture of 16151 (ex 498) and shows the groove up much better than the picture I showed of 498. Will these NRM pictures be available to us at some time? That one looks an excellent one for working out longitudinal dimensions since the camera seems to be broadside on, exactly opposite the centre of the locomotive.

Jim G

[jim mac]

There will be an update on the NRM project in TTL121 due in July; the long term aim is that all the images will be available in a seachable database, but as the copyright will remain with the NRM, the details need to be agreed. They should be accessible at the Search Engine later in the year, but an online version is not imminent.
jim mac

[JimG]

There will be an update on the NRM project in TTL121 due in July; the long term aim is that all the images will be available in a seachable database, but as the copyright will remain with the NRM, the details need to be agreed. They should be accessible at the Search Engine later in the year, but an online version is not imminent.
jim mac

Jim,

Thanks for that. I'll hang on till the back end of the year.

Jim G.

[JimG]

Just to add to the thread with the latest development, I did a trial run of constructing a complete wheel. I had managed to get a copy of the actual wheel drawings from the Campbell Cornwell archive with the help of Jim Mac and I re-did all my measurements to match that drawing.

craWheel01.jpg (74.25 KiB) Viewed 22627 times

One thing I forgot to do was reduce the depth of the boss to match the depth of the balance weight. I left the boss face a bit higher since I did the final shaping of the spokes by hand and I didn't want to run the risk of damaging the finished edge of the boss while doing this. The balance weight is "separated" so will be for a model of 498 or 499.

The work on the six wheels for the locomotive is underway at the moment with most of the work having been done in shaping the spoke area before cutting the spokes.

craWheel02.jpg (104.94 KiB) Viewed 22627 times

Work has come to a halt at the moment since I broke my one remaining 0.4mm cutter when doing the final shaping of the balance weights so I'll have to wait till I get a replacement cutter to finish them all off.

Work is still progressing on deciding on an accurate drawing for the class with help from Jim Mac, Allan Ferguson and Jim Watt. I think I'm getting towards something which I'm happy with.

Jim.

[Victorian_Lad]

Jim,
I think Mike's picture is pretty conclusive, but here is a pre-group shot from a low angle (Dawsholm/ Maryhill area I think) of CR No 510, and 2 later close-ups, LMS 16153 and BR 56154 (ex CR Nos 527 & 528), just to confirm nothing changed.

CR No 510 .jpg

498 wheels.jpg

Dave L

Hello,
I am very curious about the symbol of the object on the 498 Class underneath the bufferbeam. It doesnt looks like a masonic symbol I am aware of (many CR engines had them burnished into them) so would anyone know what the symbol is?

Kris

[jasp]

Well spotted Kris!
Definitely not a Masonic symbol.
Can anyone clarify?
Jim P

[Jim Summers]

My opinion is that it is just decoration for reasons of sheer pride.
However, what about the white right angle above the coupling hook? That might have symbolism, but it is an odd place. I am sure it is not a route indicator.

JimS

[caley739]

My opinion is that it is just decoration for reasons of sheer pride.
However, what about the white right angle above the coupling hook? That might have symbolism, but it is an odd place. I am sure it is not a route indicator.

JimS

It could be a square and likely is a Masonic symbol, which leads me to think the circular device might also have Masonic significance, perhaps relating to a local lodge.

Tom Robertson

[jasp]

Enlarging the pic, behind the coupling hook appears to be a “diamond” shape which may have thickness, or perhaps just a contrasting line at the edge.
Jim P

[David Blevins]

I have tried to enlarge the "engraving" below the buffer, but it still comes up slightly blurred.
I think it looks like the "Polish Eagle", which I am sure you will think I must have been drinking Polish Vodka over the New Year!
I am enclosing a few photographs of enlarged Polish Eagles with Crown, period 1919 to 1945, to see if you cam make any comparison.
Here follows a short History lesson (humour) to perhaps support my suggestion even if it doe's sound a bit far fetched:-
The CR Loco No. 510 was Built in 1920, pretty close to when Poland obtained it's Freedom, declaring Independence in Nov., 1918, followed by the Versailles Treaty of 28/06/1919, followed by further Fighting over territory, literally and negotiating up to 1920. The Locomotive in the photograph looks as if it has just arrived from St Rollox, and has been placed in the Head Shunt besides the Bridge near the River Kelvin at Dawsholm Shed in Glasgow, where it has been photographed in Paint Shop Condition. Would such engraving take place at St Rollox where they would have all the suitable equipment or as more commonly thought engraved by the Driver at the Local Engine Shed?
I believe it looks like a Polish Crowned Eagle, could there have been a Polish Exile working on the Caledonian Railway in 1920 and it was engraved to show his Families identity and Pride!

One other though, is that engraving on the Chimney below the cap, strange markings!

David Blevins.

[David Blevins]

Can anyone see a resemblance to a Polish Crowned Eagle or is it just me?

David Blevins

[John Lindsay]

I'm convinced by the Polish eagle idea. I also agree that the plate behind the drawhook is a full diamond.

I've also never noticed a burnished edge on a smokebox without wing plates before - perhaps I'm just not observant.

Cheers

John

[Dave John]

It does look like it, though odd that it is down there rather than fitted somewhere above the footplate.

While we are on about decorations I noticed the rather fancy finial on top of the dome. A fun job getting up there to polish it nightly.

[David Elvy]

A wild guess but I think the "finial" on top of the dome is possibly the regulator lubricator oil pot.

David