Brighton Atlantic: 32424 Beachy Head

link http://www.bluebell-railway.co.uk/bluebell/locos/atlantic/latest.html

 

Update on the Atlantic project showing the excellent news that the loco is now on its wheels, giving a real sense of what she will look like when complete. At the moment, there are still a few jobs to complete on the chassis, so the frames are still propped up about 9" above their final level, but it is hoped to finally lower them soon.

Also a reminder that Atlantic House will be open for project supporters to come and see progress on 21/22 June and again for the general public during the Model Railway Weekend, 28/29 June.

http://www.bluebell-railway.co.uk/bluebell/locos/atlantic/latest.html

Tom

 

I never appreciated how small the gap between the driving wheels was. Looking really good though and progressing nicely.

 

Yes, it was an eye opener for me too when I had a look a couple of weeks ago! It's not something that is very apparent in historic photos that are typically a 3/4 head on view.

Tom

 

With such a small gap between the driving wheel flanges presumably one has to have considerable faith in the rigidity--in terms of any minimal " fore and aft" movement--in respect of the coupled wheel axleboxes. Flanges striking flanges would not be good!

Loco looks great and is coming on well. Do we know if any preparatory work is being undertaken on the boiler unit yet?

46118

 

Quite a lot has gone on behind the scenes - the boiler is detubed, and a number of the surfaces where fittings go (regulator, gauge glasses etc) have been cleaned up and machined; also I believe there has been some work around the mud hole doors.

I'm not sure what the "running order" is from here in terms of boiler overhaul, construction of tender body etc.

Tom

 

Quick update - there is an updated sponsorship list of components for Beachy Head.

http://rasalmon.co.uk/bluebell/download/atlanticsponsorship.pdf

She certainly looked impressive the other week sitting on all her wheels at the open day. There was also a very nice Victorian pen and wash sectioned diagram of a JC Craven / Beyer Peacock 2-4-0 pinned on a display board: pure coincidence I'm sure.

Tom

 

Latest project update is here:

http://www.bluebell-railway.co.uk/bluebell/locos/atlantic/latest.html

Highlights include the pattern for the superheater header, a start on the valencing, the smokebox door, addition of cylinder cladding and white-metalling of eccentric straps.

Tom

 

Fascinating....workmanship is superb....

 

The latest edition of Atlantic News came to subscribers the other day. A few highlights from the engineering report - purely a personal view of what leapt out at me:

- The running boards are being assembled. As Fred Bailey notes: "Some parts for the running boards we have had in stock for some years, and they are simply cut and rolled pieces of steel plate. The 'Brighton' must have had heavy crews as these are all made from 3/8" and 1/2" steel plate and angle irons - brick built outhouses come to mind!"

- The grate is being designed for the firebox. Interestingly, the original 'Brighton locos had a sloping grate and the fire bars ran the complete length of the firebox in one section. The GN/LNER Atlantics had a grate that had a change of slope, with sloping front half and a level back half, and fire bars in two sections. Beachy Head will obviously need to have the GN pattern as it is a GNR pattern boiler, but it turns out that there are rather more Brighton drawings! So new drawings are having to be made for the components of the grate.

- As is well known, a lot of the new patterns for Beachy Head have been traditional wooden patterns; however, Fred has started to work with 3D CAD and some polystyrene patterns have been made, initially to produce parts for the steps.

- Finally, and back to the boiler: The GNR Atlantics had two "pop" safety valves, whereas the Brighton Atlantics had two Ramsbottom valves. Obviously the boiler has fittings for "pop" valves, but they would give a significantly different character to the locomotive. So, also using 3D CAD, a design for a double-Ramsbottom safety valve body has been designed that can be fitted to the fittings for the pop valves on the boiler.

On the financial front, there is a new component list for sponsoring: http://www.bluebell-railway.co.uk/bluebell/locos/atlantic/componentlist3.html Interestingly, the final square foot of Atlantic House has now been sponsored. (Atlantic House was part sponsored at £30 per square foot, for 500 square feet). It's touching that the late David Haggar (well known as a photographer on this site and others) left a legacy which helped sponsor the driving wheel splashers.

Tom

 

Re: the heavyweight platework, can't have anything to do with getting weight over the drivers can it? The advice I was given with my 3 1/2" gauge 440 was to get as much over them as possible to help adhesion. Assume the same principle would work with an Atlantic?

 

Interesting thought, but I suspect probably not that significant. I had to do the calculation to see just how much difference it does actually make.

Doing a quick fag packet calculation. Assume that part of the running plate over the two driving wheels is say 5m long by 0.75m wide. Density of steel is about 7500kg/m^3. There are obviously two running plates.

That gives a mass of the two plates, if they are 12.5mm (1/2inch) thick of:

= 2 * 5 * 0.75 * 0.0125 * 7500
= 700kg

So the additional adhesion gained by using say 1/2" plate rather than 1/4" is half that amount - say 350kg or 175kg on each axle. It would make you say "ow" if you dropped one on your foot, but probably not that significant as a make or break for whether you get through the tunnel or not with seven on!

Tom

 

Dependent on the fixing method, it could add substantially to the rigidity of the frames in both the vertical and horizontal planes, a point made by Eric Langridge in "Under 10 CMEs".

 

Do the running plates support the brackets that support the slide bars? If so that is a good reason for a lot of strength at least in that area.

 

I don't think so - the motion brackets are riveted to the frames. See this photo from earlier this year:



Tom

 

Thanks for that. The brackets do clearly need to be fixed to the frames, but I was wondering whether they might get some support from the running plates as well. Thinking about it, however, I realise that the forces on the motion bracket are almost purely up and down, and to withstand those the attachment to the frame is essential while any attachment to the running plate would make negligible difference. So the flat bit at the top is presumably just to support the running plate.

 

I think what Mr Langridge was getting at was more to do with frame deflection in the lateral direction, particularly if they were being lifted without the support of the boiler and with the horn ties removed. Normally, a works would put the frames minus wheels on to stands distributed along the frame, and then remove the boiler, but as in Crewe's belt system, the frames would then be moved along the shop to the respective gangs for particular work to be carried out.

 

Fair enough Tom! Good calculations by the way, I wouldn't have a clue where to start...

 

If you're working in imperial , 1/4" plate weighs near enough 10lb/sq ft. Fairly simple to calculate platework weight on this basis, even without a calculator.