BR Standard class 6 No. 72010 'Hengist' and Clan Discussion Thread

See Loco Engineering MIC - rivets v fitted bolts thread. Ray.

 

Are you sure there is a difference between the construction of MNs and WC/BBs?

I've just looked up in Bradley, who is usually pretty thorough, and he has the following to say about MN frames: (my emphasis)

"The main frames with welded hornblocks were centred above the axle boxes, thereby giving one centre line for the frames, boxes, guides and springs, and cut out offset thrust. Hitherto, this had been one of the main advantages of bar framing, and was a feature perpetuated by the BR Standard Classes. Exceptionally good horizontal cast-steel racking stays were provided, although the bracing was weakened when holes had to be enlarged, and others cut, and lighter fabricated stays and plates substituted in order to reduce weight."

Concerning the WC/BBs, he doesn't specifically speak about the frames, but simply says:

"All the principal Merchant Navy features were present […]"

Which suggests to me that the horns of both MNs and WC/BBs were welded, with no significant differences in construction method.

Tom

 

Tom,
Can I refer you to the Southern Railway Axlebox Guide drawing E 30260 for the Merchant Navy Class. This is a casting retained by fitted bolts.

 

Lets also remember that there were three batches of MNs, each with detail differences. Who's to say that some had castings retained by bolts and others were welded? Are subsequent modifications noted on original works diagrams?

 

That is correct. Order Nos 1068 1189 and 3393. The frame plate drawings for 1068 and 1189/3393 all show holes drilled in them to retain the axlebox guides using fitted bolts.

 

Which makes me wonder why Bradley mentions their being welded - especially as he is generally very accurate in his descriptions, and punctilious in mentioning significant differences between locos in a class, having access at the time to the various works records and, in the case of the Bulleid designs, also the ability to talk to those in the workshop who built the locos. (Volume 2 of "Locomotives of the Southern Railway", which covers the pacifics, came out in 1976 and presumably the research was done rather earlier, so plenty of people to speak to concerning construction details).

Tom

 

I know that this is the 72010 thread but we were talking about welded hornguides in general and, in their simplest form, these are a U shaped piece of metal which is welded into the frames and to which renewable liners are fitted. In their simplest form they can be forged from a heavy (hefty was my term!) piece of plate.

 

On that we are in total agreement. However Riddles, Cox and their acolytes elected to go for cast ones. It might be an interesting intellectual exercise to discover the percentage welded v riveted/fitted bolted (is there such term?) across the UK engine fleet.

 

I'm very happy to report that more progress has been achieved with the delivery of the 2nd combined frame stretcher / spring hanger and the rear stretcher / brake cylinder support. The photo above shows the new rear stretcher to the left with the 2nd combined frame stretcher, 1st combined frame stretcher and the buffer beam with oval buffers.
Progress continues with the frame profiling at Stephenson Engineering. A full update is available on our website due to the sheer volume of news!

 

The latest news is now on the website. The frames have been pre-machined ready to accept the welding in of the horn guides. The size of the machine used at Stephenson Engineering makes the frames look like OO gauge copies.
Many thanks to Robert Stephenson for the photos. And yes, for those who have asked, this is the same Stephenson family descended from the great George Stephenson so we are in good hands!

 

That machine is a tiddler......believe me....built in Yorkshire of course............note Victor..........

 

As an IT 'engineer' with experience on loco restoration being under tarpaulins or in sheds with limited engineering facilities it impressed me
Built in Brighouse, just down the road from where we have our regular engineering meetings which unintentionally goes with our 'Make the most of British Engineering' philosophy.

 

Know the company well, the MD is a personal friend. Some of the machines they have built in the past would dwarf that one, sadly not these days........

 

Its amazing to see a rejuvinated project making such fast progress. Those combined stretchers look lovely.

 

Thanks Pesmo. There is an awful lot of hard work going on and not only are we planning the frame assembly and entering the planning phase for the cylinder blocks but there is the matter of certification and and ensuring that everything we do is compliant ready for mainline running.
If we can get more people involved at in volunteering and sponsoring components we stand a very good chance of having assembled frames at Loughborough late 2014 or early 2015.
Shameless plug : membership forms are available on the website along with the ability to make donations to the project!
Dave

 

Very impressive Dave!

Could I ask why the buffers are oval? I've only seen circular ones on Clans, I thought....

 

BR Lot 242 (of which Hengist was to be the first) were due to have oval buffers fitted. We hold both oval and round buffers in stock allowing us some flexibility when she's up and running.
Thanks for the question!

 

Thanks Dave - really interesting.

 

The second batch of Clans were due to have quite a number of differences incorporated. Not least of which was the Combined Stretchers and Spring Brackets broadly à la DoG which you see on the Hengist web site. The 10 earlier Clans had an arrangement (nearly?) identical to that of all three batches of Brits. It is thought, had a forth batch of Brits been built, they would have incorporated the same improvements

 

Makes sense, many of the best designers like to have components that fulfil two jobs at the same time. I will be applying for membership in the new year